ALBERT

Notes: Von Dichlorotris(dimethylphenylphosphan)-nitridotechnetium(V), [TcNCl2(MePhP)3] werden durch schrittweisen Ligandenaustausch mit Diethyldithiocarbamat Komplexe der Zusammensetzung [TcN(Cl)(Me2PhP)2(Et2dtc)], [TcN(Me2PhP)(Et2dtc)2] und [TcN(Et2dtc)2] dargestellt. Die Reaktion mit N,N-Diethylthiocarbamoylbenzamidin, H2Et2tcb, liefert dagegen in guten Ausbeuten das Bis-Chelat. Als einziges Intermediat der Reaktion läßt sich [TcN(Cl)(Me2PhP)2-(HEt2tcb)] isolieren.[TcN(Me2PhP)(Et2dtc)2] kristallisiert in der monoklinen Raumgruppe P21/c mit a = 17,369(5) Å, b = 15,024(1) Å, c = 9,906(3) Å, β = 76,47(1)º, Z = 4. Der Me2PhP-Ligand ist äquatorial koordiniert. Die auffällig kurze Mehrfachbindung zwischen Technetium und Stickstoff (Bindungslänge Tc—N(1) 1,624(3) Å) wirkt sich stark labilisierend auf das trans-ständige Donoratom aus (Abstand Tc—S(4) 2,826(1) Å).[TcN(HEt2tcb)2] kristallisiert in der triklinen Raumgruppe P1, mit a = 9,749(4) Å, b = 11,264(4) Å, c = 12,359(4) Å, α = 75,34(2)º, β = 79,69(2)º, γ = 87,55(2)º, Z = 2. Das Koordinationspolyeder ist eine quadratische Pyramide, deren Spitze vom Nitridoliganden besetzt ist. Ihre Grundfläche wird von den Donoratomen der cis-koordinierten Chelatliganden gebildet. Das Metall befindet sich um etwa 0,6 Å über der Grundfläche. Der Tc≡N-Abstand beträgt 1,610(5) Å.

Notes: The crystal structure of (C6F5S)3N has been examined. The compounds (C6F5S)2NX, X = SiMe3 and ½ Hg have been prepared from (C6F5S)2NH and characterised. In a number of other reactions, such as oxidation and irradiation, the S—N bond in (C6F5S)2NH was readily fractured, forming the disulfide, (C6F5S)2. The compound (C6F5S)3N has been found to be unreactive. Details of the mass and 13C NMR spectra of (C6F5S)nNH3-n, n = 1, 2, 3 are reported.

Notes: FeMes2, 1, und FeTrip2, 2, bilden Komplexe der Koordinationszahl (KZ) vier. Mit großvolumigen Liganden wird jedoch nur ein Donor angelagert. Die Kristallstrukturen von [1(col)] (KZ 3) und [2(py)2] (KZ 4) werden mitgeteilt.

Notes: Im System Zn/Mo/O sind mehrere ternäre Phasen bekannt. Bei 900°C sind die Phasen ZnMoO4, Zn2Mo3O8 und Zn3Mo2O9 stabil. Die Koexistenzgebiete sind am ternären Phasendiagramm dargestellt. Die Strukturbestimmung von Zn3Mo2O9 erfolgte mit Röntgenbeugung an Einkristallen. Die Verbindung kristallisiert in der monoklinen Raumgruppe P21/m (a = 7,757(1) Å, b = 7,132(1) Å, c = 8,370(2) Å, β = 117,40(1)º, Z = 2).

Notes: Die P—N-Sodalithe Zn8[P12N24]X2 mit X = O, S, Se, Te wurden durch Umsetzung von HPN2 mit dem jeweiligen Zinkchalkogenid ZnX bei 750°C dargestellt. Sie kristallisieren in einer aufgefüllten Variante von Zn7[P12N24]Cl2 und somit isotyp zu Zn8[B12O24]O2 (I43m, a = 823 bis 830 pm, Z = 1) Die P—N-Sodalithe enthalten im Zentrum ihrer β-Käfige XZn46+-Einheiten, die als kleinstmögliche Ausschnitte aus den Strukturen von II/VI-Halbleitern angesehen werden können. Die UV/Vis-Spektren der Verbindungen zeigen im Vergleich mit makrokristallinen binären Zinkchalkogeniden gemäß dem Größenquantisierungseffekt eine Blauverschiebung der Absorptionskante.

Notes: Stannylene und Stannane mit substituierten Disilylamino-Substituenten eignen sich als Edukte für die Transmetallierungsreaktion zur Synthese von Calcium-bis(disilylamiden). Anwendung fanden Bis[2,2,5,5-tetramethyl-2,5-disilaaza-cyclo-pentyl]stannylen 1 und Bis[trimethylsilyl-tris(trimethylsilyl)silylamino]stannylen 2 (monoklin, P21/c, a = 1492,6(2), b = 1705,2(2), c = 1865,3(3) pm, β = 109,03(2)º, Z = 4). Bei der Verwendung von 2 greift das destillierte Calcium allerdings nicht nur die Sn - N-, sondern auch die N—Si-Bindung an. Ähnlich wie bei dem Quecksilber-bis[trimethylsilyl-tris(trimethylsilyl)silylamid] 3 beobachtet man bereits bei Tageslicht die homolytische Spaltung der Sn—N- bzw. Hg—N-Bindung und die Bildung des Trimethylsilyl-tris(trimethylsilyl)silylamino-Radikals 5 (g = 2,00485; a(N) = 16,2G). Der heterogen geführte Zinn-Calcium-Austausch bei Verbindung 1 in THF führt in guten Ausbeuten zum Tris(tetrahydrofuran-O)calcium-bis[2,2,5,5-tetramethyl-2,5-disilaaza-cyclo-pentanid] 4 (monoklin, P21/n, a = 1060,9(2), b = 1919,3(5), c = 1686,0(3) pm, β = 90,30(2)º, Z = 4). Auch die Stannane Men-4Sn[N(SiMe3)2]n mit n = 1 oder 2 eignen sich als Synthone zur Synthese von Bis(tetrahydrofuran-O)calcium-bis[bis(trimethylsilyl)amid].

Notes: Purple colored single crystals of the β-modification of Li3TiF6 have been prepared by heating an appropriate mixture of LiF and TiF3 at 820°C under an argon atmosphere. β-Li3TiF6 crystallizes in C2/c with a = 14.452(2) Å, b = 8.798(1) Å, c = 10.113(1) Å and β = 96.30(1)º. The structure is isotypic to β-Li3VF6 and contains isolated compressed TiF6 octahedra (dTi-F = 1.91-2.01 Å). Magnetic properties of β-Li3TiF6 were studied and discussed. Band structure calculations and calculations of the Madelung part of the lattice energy, MAPLE, were performed to discuss the chemical bonding.

Notes: Die Verbindungen UrPrIx mit x = 5 und 7 lassen sich durch Umsetzung von N-Propylurotropiniumiodid UrPrI mit überschüssigem Iod I2 bei Raumtemperatur aus wäßriger Lösung gewinnen. N-Propylurotropiniumpentaiodid C9H19N4I5 kristallisiert in der monoklinen Raumgruppe P21/n mit a = 1007,6(3) pm, b = 1362,5(3) pm, c = 2899,0(9) pm, β = 91,49(3)º und Z = 8. In der Kristallstruktur ordnen sich Kationen UrPr+ und Dimere aus stark aufgeweiteten V-förmigen Anionen I5- entlang [0 1 0] zu parallelen Strängen an. N-Propylurotropiniumheptaiodid C9H19N4I7 kristallisiert in der triklinen Raumgruppe P1 mit a = 970,4(1) pm, b = 971,1(1) pm, c = 1357,8(2) pm, α = 106,83(1)º, β = 92,28(1)º, γ = 105,17(1)º und Z = 2. In der Kristallstruktur wechseln sich Doppelschichten aus Kationen UrPr+ und aus vernetzten Anionen I7- längs [0 0 1] ab.

Notes: Die Synthese der Koordinationsverbindungen [ML(HL)(H2O)] mit M = La3+, Ce3+, Pr3+ und Nd3+ und H2L = 7-Oxa-bicyclo[2.2.1]heptan-2-exo,3-cis-dicarbonsäure (1) wird beschrieben. Ergebnisse der IR-Spektroskopie und thermoanalytischer Untersuchungen werden mitgeteilt. Nach den Ergebnissen von Röntgenkristallstrukturanalysen sind die vier untersuchten Lanthanoid(III)-Komplexe isotyp. In ihnen ist das Metallatom in dreifach überkappter trigonal-prismatischer Koordination von neun O-Atomen als nächsten Nachbarn umgeben. Dabei tritt der bicyclische Ligand einmal als dreizähniges Monoanion HL- und zum anderen als fünfzähniges Dianion L2- mit Brückenfunktion auf. Die neunte Koordinationsstelle wird von einem Wassermolekül besetzt.

Notes: The new compound HfNixP (x = 0.426(1), crystal structure: P63/mmc, a = 3.737(1) Å, c = 12.666(2) Å, V = 153.21(7) Å3) has been prepared by arc-melting of HfP with nickel and subsequent annealing at 1400°C. Its crystal structure can be considered as a filled HfP structure, with the Ni atoms inserted into the trigonal prismatic voids of the Hf sublattice. Since the neighboring trigonal Hf6 prisms are centered by P atoms, each of the three rectangular faces of the Hf6Ni prism is capped with one P atom. Altogether, the structure of HfNixP consists of alternating layers of Hf atoms with the packing sequence AABB. One P and the Ni position are situated between the eclipsed Hf layers, whereas the other P site between the A and B layers is surrounded by six Hf atoms in a staggered arrangement. The calculated density of states (Extended Hückel approximation) points to metallic conductivity; threedimensional metallic behavior is assumed because of the Hf-Hf bonding interactions along all three directions.

Notes: Blaue Di(phthalocyaninato(2-))metallate des dreiwertigen Yttriums und Indiums werden durch die Reaktion von Yttriumacetat und wasserfreiem Indiumchlorid mit geschmolzenem Phthalodinitril in Gegenwart von Kaliummethylat dargestellt und als Komplexsalze voluminöser organischer Kationen isoliert. Die anodische Oxydation von (nBu4N)[M(Pc2-)2] (M = Y, In) liefert Kristalle von grünem, paramagnetischem Di(phthalocyaninato)metall(III)-dichlormethan-Solvat, [M(Pc)2] · CH2Cl2 (μeff = 1,8/1,9 B.M. (Y/In)). Rotbraunes Di(phthalocyaninato)metall(III)-polybromid, [M(Pc-)2]Brx wird durch die Oxydation mit überschüssigem Brom präpariert. Die Redoxeigenschaften der Di(phthalocyaninato)metallate(III) werden mit der zyklischen Voltammetrie und Differenzpulspolarographie untersucht. Ein quasi-reversibler (ΔE ≃ 60 mV) Einelektronen-Prozeß bei 0,09 V (Y) und -0,07 V (In) wird dem Redoxpaar [M(Pc2-)2]-/[M(Pc)2] zugeordnet. Weiterhin wird über die elektronischen Absorptions-sowie MIR/FIR- und Resonanz-Raman-Spektren berichtet. Die charakteristischen Merkmale der drei verschiedenen Oxydationszustände werden in Abhängigkeit vom Radius und der Elektronenkonfiguration des Metallions diskutiert.

Notes: Farblose Ionenkristalle des Carbonyl-kupfer-Komplexes [(NH3)3(CO)Cu][Co(CO)4] (1 a) entstehen bei der Reaktion von [Cu(NH3)4]Cl und Na[Co(CO)4] (T 〈 - 8°C, 1 bar CO-Druck); oberhalb -5°C und unter N2-Atmosphäre entsteht aus 1 a [(NH3)2CuCo(CO)4] (C), von dem ausgehend weitere Cobaltate zugänglich sind: Die Amine N-Amino-piperidin, N,N-Dimethyl-ethylendiamin (dmed) und N-Benzyl-N′,N′-dimethyl-ethylendiamin (bn-dmed) verdrängen NH3 unter Erhalt der Cu—Co-Bindung zu [(C5H10N—NH2)3CuCo(CO)4] (1 b), [(dmed)CuCo(CO)4] (1 c), [(bn-dmed)CuCo(CO)4] (1 d). Das zu C isostere [(NH3)2CuFe(CO)3NO] (2 a) entsteht bei der Reaktion von [Cu(NH3)4]Cl und Na[Fe(CO)3NO] in wäßriger Lösung; mit N,N,N′,N′-Tetramethylethylendiamin (tmed) wird aus 2 a [(tmed)(NH3)CuFe(CO)3NO] (2 b) erhalten. Mit dem [Mn(CO)5]--Ion bildet sich dagegen unter den für 2 a angegebenen Reaktionsbedingungen der ammoniakärmere, heteronukleare Vierkerncluster [{(NH3)CuMn(CO)5}2] (3). Alle neuen Verbindungen sind durch Einkristallstrukturanalyse gesichert.

Notes: Die neuen Verbindungen SnRh3B1-x (x ∼ 0,2, tetragonal, P4/mbm, a = 570,31(2) pm, c = 835,99(8) pm, Z = 4, 514 Reflexe, 26 Parameter, R = 0,026), Sn4Rh6B (hexagonal, P63/mmc, a = 560,01(3) pm, c = 1367,5(1) pm, Z = 2, 746 Reflexe, 17 Parameter, R = 0,035) und Sn5Rh6B2 (hexagonal, P62m, a = 654,80(7) pm, c = 557,32(9) pm, Z = 1, 361 Reflexe, 16 Parameter, R = 0,039) wurden durch Reaktion der Elemente dargestellt. SnRh3B1-x kristallisiert in einem aufgefüllten U3Si-Typ, einer verzerrten Variante des kubischen Perowskits; Sn4Rh6B läßt sich von der Struktur des hexagonalen Perowskits BaNiO3 ableiten. Beide Verbindungen enthalten nahezu reguläre Rh6B-Oktaeder. Sn5Rh6B2 ist isotyp mit Sn5Ir6B2 und enthält isolierte Säulen aus trigonalen Rh6B-Prismen.

Notes: Die Kristallstrukturen von Sb(SC6H5)3 (1), Sb(SC6H2Me3-2,4,6)3 (2) sowie der neuen Verbindung SbI(SC6H2Me3-2,4,6)2 (3) wurden mit Hilfe von Röntgenbeugungsmethoden bestimmt. Zusätzlich zu der erwarteten trigonal pyramidalen Umgebung von Antimon werden für 1 und 3, nicht jedoch für 2, intermolekulare Wechselwirkungen beobachtet (1: Sb … C: 363,3 pm; 3: Sb … S: 2 × 369,4 pm). Die Ursachen für diese Unterschiede werden diskutiert.

Notes: Trans,trans-[MoX2py4][MoX4py2] (X = Cl, A; Br, B; py = pyridine, C5H5N) are the side products of reaction of between (NH4)2[MoX5 · H2O] (X = Cl,Br) with pyridine diluted with methanol.Both trans,trans-[MoX2py4][MoX4py2] are monoclinic, P21/n space group, with z = 2 and: a = 12.568(1), b = 9.430(1), c = 14.952(1) Å and β = 100.81(1)° (A); a = 12.551(2), b = 9.533(2), c = 15.366(2) (Å) and β = 99.35(1) (B).Cations and anions are located on the symmetry centers and have eclipsed conformation of the trans located pyridine ligands. Average Mo—X and Mo—N (pyridine) bonds are; (cation) 2.41, 2.21 Å (A); 2.54, 2.21 Å (B); (anion) 2.44, 2.20 Å (A); 2.58, 2.20 Å (B).Anionic part of the compounds can be oxidised by bromine to trans-MoX4py2, which precipitates from the solution. Cation can be isolated from the solution in the form of trans-[MoX2py4]Br3 (X = Cl, Br).The compounds were also characterised by chemical analysis, infrared spectroscopy and conductivity measurements.

Notes: Reaction of a 1:2 mixture of Y[N(SiMe3)2]3 and Ba[N(SiMe3)2]2 with tBuOH (8 mol equivalents) in Et2O at 25°C yields YBa2(OtBu)7(tBuOH), which has a triangular structure with two μ3-OtBu and three μ2-OtBu ligands, one terminal OtBu on Y and on one Ba, and one terminal tBuOH on the second Ba. All metals are thus five-coordinate. The crystal structure is comprised of chains of triangles of triangles held together by hydrogen bonds from tBuOH of one YBa2 unit to the terminal OtBu on Ba of the next YBa2 unit. This serves as support for the idea that, in certain cases, the heterometallic alkoxide product from alcoholysis of a mixture of two metal complexes can faithfully duplicate the global solution metal stoichiometry.

Notes: The reduction of [RuCl3(NO)(PPh3)2] (1) with Zn/Cu generates [RuCl(NO)(PPh3)2] that by ligand exchange with PR3 (R3 = iPr3, iPr2Ph) affords the stable 16-electron ruthenium (0) complexes trans-[RuCl(NO)(PR3)2] (2, 3). The X-ray structural analysis of 2 confirmed the square-planar geometry around the metal center. HCl oxidatively adds to 2 and 3 to give the octahedral ruthenium(II) compounds [RuHCl2(NO)(PR3)2] (4, 5). On treatment of 2 and 3 with CO, TCNE, CH2 (generated from CH2N2) and O2, five-coordinate 1:1 adducts [RuCl(NO)(L)(PR3)2] (6-12) are formed. The dioxygen complexes 11 and 12 react with SO2 to afford the sulfatoruthenium(II) derivatives [RuCl(NO){η2(O,O)-O2SO2}(PR3)2] (13, 14). Compound 13 (R3 = PiPr3) has been characterized by X-ray structural analysis.

Notes: The molecular zinc hydroxide complex TpCum,MeZn—OH [1, TpCum,Me = tris(3-cumenyl-5-methylpyrazolyl)hydroborate] is a powerful nucleophile. It effects stoichiometric hydrolysis of activated esters RCO—OX and amides RCO—NHX in nonaqueous media. The cleavage products are TpCum,MeZn—OCOR and HOX or H2NX, resp. Two of them (TpCum,MeZn—OCO—CH2-CH2OH resulting from propiolactone and TpCum,MeZnOCO—CF3 resulting from trifluoroacetamide) were characterized by crystal structure determinations.

Notes: The mechanisms of intramolecular dynamics in transition metal hydride complexes are surveyed in this review. The NMR data for a number of fluxional hydrides are interpreted in terms of principal and secondary topological changes of the coordinated ligands. The principal ligand motions can be further categorized as being of migratory (M) and replacement (R) type. Discussion of these ligand motions is followed by analysis of more complex rearrangements of hydride systems, in which both types are operative in multiple exchange processes. The attempted systematic approach appears to be a useful general mechanistic concept for the understanding of the fluxional behavior of hydride complexes.

Notes: The methods of preparation for Bi8(AlCl4)2 and Bi6Cl7 have been improved and the single crystal structures for these cluster compounds re-investigated and re-interpreted. In addition, conductivity measurements and band structure calculations using the tight-binding approximation have been performed on Bi6Cl7 and related subvalent bismuth halides. - Bi8(AlCl4)2 consists of isolated AlCl4- anions and rather undistored square-antiprismatic Bi82+ clusters with an average Bi-Bi distance of 3.10 Å. Relatively short intercluster Bi-Bi contacts of 3.90 Å suggest weak bonding interactions between the Bi82+ units. In contrast, the structure determination of Bi6Cl7 implies that this structure should be regarded as being composed of discrete Bi95+ clusters and a polymeric BiIII-Cl anionic lattice including infinite, distorted α1[Bi2Cl24+] chains. According to the experimental and theoretical results, the Bi6X7 (X = Cl, Br) family of subvalent bismuth halide compounds are anisotropic semiconductors along the crystallographic c axis. The conductivity is mediated by the onedimensional α1[Bi2Cl24+] chains. These are interconnected with the Bi95+ clusters, which are acting as electron reservoirs. The related BiX (X = Br, I) family of subvalent bismuth halides are shown to be anisotropic semiconductors in the crystallographic b direction.

Notes: 1,2-Di-tert-butyl-3-(diisopropylamino)-4-(dimethylamino)- 1,2,3,4-diphosphadiboretane (1) reacts with Fe2(CO)9 to give two isomeric tetracarbonyliron complexes 2, 3 with P-Fe bonds and a bis(tetracarbonyliron) complex 4. In contrast, 1 displaces the olefinic ligand from tetracarbonyl(η4-norbornadiene)metal (metal = Cr, Mo) to form the tetracarbonylmetal complexes 5 and 6 with a rearranged ligand molecule, i.e. a 1,3,2,4-diphosphadiboretane. This process is accompanied by a change of the tert-butyl groups from an anti orientation in 1 to a syn orientation in 5 as shown by X-ray crystallography.

Notes: The aza-closo-boranes ArNB9H9 (1, Ar = p-ClC6H4) and MeNB11H11 (2) were brominated, iodinated, or methylated under Friedel-Crafts conditions to give ArNB9H4Br5 (3), ArNB9H7I2 (4), ArNB9H4Me5 (7), MeNB11H10Br (5), MeNB11H10I (6), and MeNB11H5Me6 (9), respectively. The upper boron belt adjacent to nitrogen is not involved in the substitution reactions with 1 and 2. The antipodal position and the lower belt are attacked by electrophiles in the case of 1; the antipodal position is the preferred one in the case of 2. By prolongated action of triflic acid on the methylated species 7 and 9, one methyl group is replaced by the triflate group to give ArNB9H4Me4(OTrf) (8) and MeNB11H5Me5-(OTrf) (10) with this group in the positions 6 and 12, respectively. The NMR data indicate the cluster symmetries Cs (4, 8), C4v (3, 7), and C5v (5, 6, 9, 10). Crystal structure investigations of 5 (space group Cc) and 10 (space group C2/c) showed that the molecular dimensions of the NB11 skeleton are comparable to those of closo, -(PhCH2)NB11H11.

Notes: Annelated pentafulvenes 2, 10, 13, and 14 are efficiently accessible by a palladium-catalyzed domino coupling process of aryl substituted vinylic bromides 1, 9, 11, and 12, 5-Membered palladacycles 3 are discussed as key intermediates.

Notes: Monomeric nickel(II) thiosemicarbazone complexes are an attractive new class of homogeneous catalysts for the activation of silanes. However, their activity is limited by the formation of inactive oligo- and polymers. The pathway by which aggregation takes place was elucidated by the preparation and X-ray structural analysis of the first trimeric nickel(II) thiosemicarbazone complex. Aggregation was shown to proceed via Ni—O—Ni and Ni—S—Ni bridging, giving rise to both fourfold planar and pseudooctahedral coordination of the nickel ions.

Notes: Yellow tetrakis[bis(trimethylsilyl)methyl]digallane(4) 1 reacts with two equivalents of the carboxylic acids RCOOH (R = -C6H5, -p-BrC6H4, -3,5-Me2C6H3, -CMe3) to yield almost quantitatively colorless products in which two bis(trimethylsilyl)methyl groups are replaced by two carboxylato ligands. As shown by a crystal structure determination with the 4-bromo-phenyl derivative (3), the Ga—Ga bond is bridged by both carboxylato groups in a chelating manner. The Ga—Ga distance is shortened to 238.5(2) pm (1: 254.1(1) pm) and the coordination number of the Ga atoms increased to four.

Notes: Optically active titanium complexes of the formula Ti(η5:η1-C5R4SiMe2NCHMePh)Cl2 (R = H, Me), containing the cyclopentadienyl ligand linked to a chiral 1-phenylethylamido moiety, were synthesized and characterized in both enantiomerically pure forms. A single-crystal X-ray structural analysis of (S)—(—)Ti(η5:η1-C5H4SiMe2NCHMePh)Cl2 shows a conformation in which the phenyl group is turned away from the metal center. NOE measurements suggest that a related structure is retained in solution. Upon activation with n-butyllithium, these complexes show hydrogenation activity toward imines with slight enantioselectivity.

Notes: A new mixed metal titanate Ba3Fe24Ti7O53, 1 was obtained by heating stoichiometRic mixtures of BaCO3, Fe3O4 and TiO2 to 1375°C for 48 h. Compound 1 was characterized by single crystal x-ray diffraction analysis. Two of the barium ions lie in a network of channels in the bc crystallographic plane. The iron and titanium atoms were refined in a random distribution in 16 independent MO6 octahedral sites and 2 MO4 tetrahedral sites. Magnetization measurements reveal a strong magnetic ordering up to 600 K. M vs. H loop measurements show no hysteresis effects.

Notes: It is unequivocally shown that acetophenone, an oxidation product in the titanium zeolite-catalyzed oxidation of α-methylstyrene, derives from 2-hydroperoxy-2-phenyl-1-propanol as intermediate, which was detected and isolated in this reaction for the first time.

Notes: Two products, Mn2(CO)7(PMe2Ph)[μ-η2-η2-MeO2C(H)CCC-(H)CO2Me] (1) in 9% yield and Mn2(CO)6(PMe2Ph)[μ-η3-η1-MeO2CC(H)CC(H)CO2Me] (2) in 34% yield, were obtained from the reaction of Mn2(CO)8(PMe2Ph)(MeCN) with MeO2C(H)C=C=C(H)CO2Me. Compound 1 contains a bridging η2-η2-MeO2C(H)CCC(H)CO2Me allene ligand and compound 2 contains a bridging η3-η1-MeO2C(H)CCC(H)-CO2Me allene ligand in which the oxygen atom of one of the carbonyl groups is also coordinated. Compound 1 slowly converts to 2, which establishes that it is a precursor to 2. Compound 2 reacts with NEtH2 to give the mononuclear manganese complex fac-Mn(CO)3(PMe2Ph)[MeO2CCH2-C=C(H)CO2Me] (3) in 96% yield. Compound 3 contains a chelating 1,3-di(methoxycarbonyl)propenyl grouping formed by addition of a hydrogen atom to the allene and the loss of a manganese grouping. Compounds 1-3 were characterized by single crystal x-ray diffraction methods.

Notes: The tricarbonylchromium complexes chlorobenzene 1 reacts with terminal alkynes 2 through a palladium-copper-catalyzed coupling to give a variety of Cr(CO)3-complexed phenylethynyl arenes, heteroarenes and ferrocene 3 in good to excellent yield. Due to the electron-withdrawing nature of the Cr(CO)3 group these novel complexes can be regarded as organometallic push-pull chromophores. Analogously, the corresponding free ligands 4 (phenylethynyl arenes, heteroarenes and ferrocene) were synthesized by coupling iodobenzene and 2. The crystal structure analysis of the singly Cr(CO)3-complexed tolane 3e reveals a strong deviation from coplanarity of both phenyl rings by an angle of 50.9(2)° presumably due to crystal packing. Correlations are established between selected substituent parameters (σP, σI, σR, σP+ and Δπ) and the carbonyl carbon resonances in the 13C-NMR spectra for the complexes 3. The overall electronic substituent effect is transmitted to the carbonyl groups by both mesomeric and inductive mechanisms. The push-pull complexes 3 display relatively small negative solvochromicities of longest wavelength absorption band (MLCT band).

Notes: Organo-Zinc Phosphaneiminato Complexes with Heterocubane StructureThe organo-zinc heterocubanes [ZnR(NPMe3)]4 with R = CH3 (1) and n-C4H9 (2) were prepared by the reaction of [ZnBr(NPMe3)]4 with MeLi and nBuLi, respectively, in hexane solution. In a similar reaction of nBuLi with [ZnI(NPMe3]4 the phosphaneiminato complex [Zn4I(nBu)4(NPMe3)3] (3) is formed. 1-3 were characterized by IR, NMR and MS spectroscopy, and by crystal-structure determinations. 1 and 2 possess heterocubane structures in which the zinc atoms are linked via μ3-N bridges of the phosphaneiminato groups, and all bond angles in the Zn4N4 core are close to 90°. A distorted heterocubane structure is observed for 3 with one of the NPMe3 moieties replaced by an iodine atom.

Notes: The P-H-functional triferriophosphonium salts [{CpFe-(CO)2}3PH]2FeCl4 (1) and [{μ-CO(CpFeCO)2}{CpFe-(CO)2}PH]2FeCl4 (4) are easily deprotonated by DBU to the corresponding unstable triferriophosphanes 2, 5, which subsequently are oxidized by sulfur to the triferriophosphane sulfides {CpFe(CO)2}3P=S (3) and {μ-CO(CpFeCO)2}{CpFe-(CO)2}P=S (6), respectively. The photolysis of 3 results only in its decomposition by elimination of [CpFe(CO)2]2, whereas the photolysis of 6 cleaves off one CO ligand to give the new spiro compound (CpFeCO)(μ-η2-PS){μ-CO(CpFeCO)2} (7), where the P=S unit is η2-bonded to the 15-electron CpFeCO fragment, and the phosphorus atom bridges two 17-electron fragments. Compound 7 shows a new coordination mode of the PS unit where sulfur is also bound to one of the metal atoms. Compounds 6 and 7 can be regarded as first examples of a new class of PS complexes of transition metals. All compounds were characterized by IR, 31P{1H}- and 13C{1H}-NMR spectroscopy as well as mass spectrometry; for 6 the X-ray analytical data are given.

Notes: The orthoamides 2a, b (R = Ph and PhCH2) have been prepared by alkylation of the guanidinium salt 4+BPh4- with PhNa and PhCH2Na, respectively. The crystal structures of the two orthoamides have been determined by X-ray crystallography. Their reaction with CuCl2 gives 1:1 complexes. The crystal structure of the complex with 2a shows a square planar geometry around the copper atom with η2-2a and two chlorides and weak interactions two the third nitrogen atom and a C-H bond of 2a in the axial positions.

Notes: The phenyl- and vinylrhodium(I) complexes trans-[Rh(R)(CO)(PiPr3)2] (2, 3) were prepared from the chloro derivative 1 and Grignard reagents. The corresponding thiocar-bonyl compound trans-[Rh(CH=CH2)(CS)(PiPr3)2] (7) was obtained similarly from trans, -[RhCl(CS)(PiPr3)2] (6) and CH2=CHMgBr. The preparation of 6 occurred via trans- [RhCl(η2-S=C=S)(PiPr3)2] (5) as intermediate. The carbonyl complexes 2 and 3 are quite inert in the presence of CO and do not react by migratory insertion to give acylrhodium derivatives.

Notes: Reduction of the 1,4-diaza-1,3-butadiene substructure of hexasubstituted oxalic amidines with lithium metal yields the new lithium diamides 3. Subsequent reaction of 3 with various electrophiles gives the title substances 4, 5, and the acylated derivative 6, respectively. The first SET step in this reaction is the formation of monolithium radical anions 2, which were detected by EPR spectroscopy. The second electron transfer leads to the deeply colored dianions 3. - In the case of compound 3a [cis-3a · 3 Et2O], the X-ray crystal structure reveals the cisoid arrangement of the bidental ligand and three molecules of diethyl ether which are located in a 2:1 fashion in the first coordination sphere of the lithium cations. The NMR 2D-1H,6Li-HOESY investigations of 3a in [D10]diethyl ether/diethyl ether (8:1) show Li+ contacts to the hydrogen atoms of the ether molecules and to the ortho-hydrogen atoms of the aryl moieties. Results of semiempirical calculations (PM3) are throughout in acceptable agreement with the experimental data and explain the unusual coordination pattern of the lithium cations of compounds 3.

Notes: A mild and effective method for the preparation of a variety of aromatic (7a-m), heteroaromatic (7n-r), and α,β-unsaturated aldehydes (8a-f) is described. The reaction of trialkylaryl- (2a-o), heteroaryl- (2p-t), and 1-alkenylstannanes (4a-f and 5a-f) with dichloromethyl methyl ether (1, DCME) in the presence of aluminium trichloride followed by hydrolysis provides the corresponding aldehydes. In the case of arylstannanes the ipso-isomers are generally formed; the p-alde-hydes occur as side products. The electrophilic substitution of 1-alkenylstannanes with 1 leads to α,β-unsaturated aldehydes in an ipso- and stereospecific manner. A comparison of the leaving abilities of the stannyl and silyl groups shows a lower or even zero reactivity of the silyl-substituted compounds 6a-c towards the electrophile 1. In the silylstannylal-kene 6c only the stannyl group reacts whereas the stannyl function remains unaffected in the product, aldehyde 11.

Notes: A series of seven chiral, tripodal N,O,S and N,N,O ligands were prepared in which N stands for a secondary amine or imidazole donor, O for a phenol, and S for a thioether or thiol metal-binding group. Key steps are (1) the construction of ortho-hydroxyacetophenones bearing the phenolic binding group and either a thioether, a protected thiol or an imidazole substituent in the α-position, and (2) subsequent reductive amination with a primary amine. The modular synthesis allows a rapid construction of a variety of structurally related ligands. In three cases, the enantiomers of the racemic products could be separated after condensation with (R)-glyceraldehyde acetonide as chiral auxiliary. The relative configurations of the cyclic N,O- and N,N-acetals thus obtained were established by NOE spectroscopy. X-ray structural analysis of two crystalline N,O- and N,N-acetals allowed the assignment of absolute configurations. Hydrolysis of the dia-stereomerically pure acetals afforded the enantiomerically pure ligands in high yield. By comparison of their CD spectra, absolute configuration could also be assigned to the third pair of enantiomerically pure ligands.

Notes: Reaction of 1,3-di-tert-butylcyclopentadienyllithium and 1,3-di-tert-butyl-4-(trimethylsilyl)cyclopentadienyllithium with S2Cl2 gives bis(2,4-di-tert-butyl-1,3-cyclopentadien-1-yl)di-sulfane (1) and bis[2,4-di-tert-butyl-5-(trimethylsilyl)-1,3-cyclopentadien-1-yl) disulfane (2), respectively. The structure of 2 was determined by single-crystal X-ray diffraction. Compounds 1 and 2 are the first biscyclopentadienylchalcogens with the chalcogen in vinylic position.

Notes: The rhodium(II) acetate catalyzed reaction of dimethyl diazomalonate with 2-siloxy-1,3-dienes 1a-1d and 1h furnished cyclopentene derivatives 4a-4d and 4h in moderate yields. The mechanism of this unusual [4 + 1] cycloaddition is discussed.

Notes: Dimethylgold(III) chloride and bromide, (Me2AuX)2, react with bis(diphenylphosphanyl)methane (dppm, molar ratio 1:2) to give the P-monohapto complexes cis-Me2AuX(dppm) (1a, b) in quantitative yields. The products are readily oxidized by air to yield the P-hapto P′-monoxides 2a, b. Treatment of 1a, b with AgNO3 affords an ionic nitrate [Me2Au(dppm)]2 [NO3-]2 (1c), which contains a dinuclear cation. A mixed bromide/nitrate (from 1b and half the equivalent amount of AgNO3) is thermally unstable and undergoes elimination of ethane to give an ionic tetranuclear gold(I) complex [(dppm)4Au4Br2]2+ [NO3-]2 (3b). - Treatment of (Me2AuCl)2 with CH2(AsPh2)2 (dpam, molar ratio 1:2) gives cis-Me2-AuCl(dpam) (1d), the arsenic analog of 1a, which is not sensitive to oxygen. - The reaction of bis(diphenylphosphanyl)-amine (dppa) yields 1:1 P-monohapto adducts Me2. AuX(dppa), which are in equilibrium with ionic chelated systems Me2Au(dppa)+ X- (1e, f). Complex 1e is readily oxidized by air to the P-hapto P′-monoxide cis complex 2e. Treatment of 1e with AgNO3 gives the ionic nitrate Me2. Au(dppa)+ NO3- (1g). - All compounds were identified by standard analytical and spectroscopic techniques. The crystal structures of 2a, 3b, 1d, and 2e were determined by single-crystal X-ray diffraction studies.

Notes: Asymmetric hydrogenations of prochiral olefines by means of chiral rhodium(I) complexes of the type [Rh(L)(PP*)]A (L = COD, [(Z,Z)-cycloocta-1,5-diene], or NBD (norborna-2;5-diene), PP* = chiral bisphosphane forming seven-membered chelate rings, A = anion like BF4-) are often associated with induction periods caused by partial blocking of the catalyst. NBD complexes are hydrogenated faster than the corresponding COD complexes. Catalytic hydrogenation of COD/NBD mixtures and the determination of the ratio of the Michaelis constants showed that the steady-state concentration of the COD complex under hydrogen is higher than that of the NBD complex. However, under argon the NBD complex predominates owing to its higher thermodynamic stability compared with that of the COD complex as determined by 31P-NMR spectoscopy. This complete reversion of the ther-modynamically determined ratios of COD to NBD complex concentration under hydrogenation conditions was proven by means of UV/Vis spectroscopy.

Notes: Highly active catalysts for the hydrogenation of CO2 to formic acid in DMSO/NEt3 are formed in situ from [{(cod)Rh(μ-Cl)}2] and various monodentate or bidentate ligands with phosphorus as the donor atom. Formic acid concentrations up to 2.3 · 0.2 mol l-1 can be obtained in less than 6 hours at ambient temperature under a total initial pressure of 40 atm by using rhodium concentrations of 5 · 10-3 mol l-1. The changes in catalytic activities observed upon structural changes of monodentate ligands are discussed in terms of classical ligand parameters like basicity and steric demand of the PR3 group, while with bidentate ligands R2P(CH2)nPR2 the chain length n plays a dominant role for the activity of the catalyst. The effects cannot be explained by a direct impact of the ligand on catalytically active intermediates only, but influences on the formation of these species must also be taken into account.

Notes: Phosphane Iminato Complexes of Arsenic. Crystal Structures of [AsCl(NPMe3)]2Cl2, [AsCl(NPMe3)2SbCl4]SbCl6, and [AsCl(NPMe3)2SnCl4] · CH3CN[AsCl(NPMe3)]2Cl2 (1) was prepared by the reaction of arsenic trichloride with the silylated phosphane imine Me3-SiNPMe3 in acetonitrile solution. According to the crystal structure determination, 1 has an ionic structure with [AsCl(NPMe3)]22+ ions, in which the As atoms are linked by the μ2-N atoms of the NPMe3- groups. Compound 1 reacts with antimony pentachloride to give [AsCl(NP-Me3)2SbCl4]+SbCl6- (2), with tin tetrachloride to form [AsCl(NPMe3)2SnCl4] (3), which is isoelectronic to the cation of 2. In 2 and 3 AsCl(NPMe3)2 acts as a chelating agent forming and , respectively, four-membered ring structures.

Notes: Chiral Tripod Ligands with Phosphorus and Sulfur Donors. Synthesis and Complex ChemistryNeopentane based tripod ligands CH3C(CH2X)(CH2Y)-(CH2Z) with mixed donor groups X,Y,Z (PR2, SR, SH) are accessible via two different strategies. The functionalized thietane CH3(CH2X)ČH2SCH2 allows stepwise introduction of P or S donors by substitution of the mesylate function and subsequent nucleophilic cleavage of the thietane ring. Tripod ligands 5 [CH3C(CH2X)(CH2Y)(CH2Z)] with up to three different donor groups (X = SH; Y = PPh2; Z = P(4-Tol)2, SCH2Ph, PPh2) are thus available. As an alternative the neopentane derivatives 8 [CH3C(CH2X)(CH2Y)(CH2Cl)] which are easily assessible from CH3C(CH2OSO2Me)(CH2Br)-(CH2Cl) (7) by stepwise substitution with phosphides LiPAr2 (Ar = aryl) may be transformed to 9 [CH3C(CH2X)(CH2Y)(CH2SBzl)]. Under controlled conditions the S - benzyl bond of 9 is cleaved reductively without concomitant cleavage of P - Ar bonds. Ligand 5a [CH3C(CH2PPh2)2(CH2SH)] reacts with Ni(BF4)2 · 6 H2O to yield the dinuclear species [(CH3C(CH2PPh2)2-(CH2S)Ni)2]2+ (10). The two ligands are bonded in an equivalent way with each of the two nickel centers interacting with one of the two phosphane functions of the ligand; the thiolate functions form μ2-SR bridges between the two nickel atoms. The SCH2 group at the four-membered S2Ni2 ring are in mutual cis position with the four-membered ring bent along the sulfur-sulfur axis by 70°. The internal strain in 10 is analyzed by comparing its structure with the ones of [(CH3C(CH2-PPh2)3NiSPh)2]2+ (11) and [(CH3C(CH2OH)(CH2PPh2)2-NiOH)2]2+ (12).

Notes: Complexes of Halide Ions with 1-Halogen-2-phenylacetylenes. Crystal Structures of PPh4[X(I - C≡C - Ph)4] with X = Cl, Br, I, of PPh4[Br(Br - C≡C - Ph)4], and of NMe4[F(I - C≡C - Ph)2]Herrn Prof. Dr. H. Brunner zum 60. Geburtstag gewidmet.The complexes PPh4[X(I - C≡C - Ph)4] with X = Cl (1), Br (2), I (3), PPh4[Br(Br - C≡C - Ph)4] (4), and NMe4[F(I - C≡C - Ph)2] (5) were prepared from the corresponding salts PPh4X and NMe4F, respectively, with the 1-halogen-2-phenylacetylenes X - C≡C - Ph (X = Br, I) in dichloromethane solutions. 1 - 5 form colourless crystals, which were characterized by vibrational spectroscopy. According to the crystal structure determinations the halide ions in 1 - 4 are coordinated by the halogen atoms of the 1-halogen-2-phenylacetylenes in a tetragonal-pyramidal fashion. The fluoride ion in 5 is only twofold coordinated with a bond angle I - F - I of 110.45°.

Notes: The synthesis and coordination chemistry of 2-(2-pyridyl)-phosphinines and 2,2′-biphosphinines are reviewed. A noteworthy series of homoleptic complexes of 4,4′,5,5′-tetramethyl-2,2′-biphosphinine (tmbp) with Cr(0), Mo(0), Wo(0) and Ni(0) are described. A [Cu(bpy)(tmbp)]+ cationic polymer has been characterized by X-ray analysis. Ruthenium, manganese and rhenium chelates were also obtained. With Mn2(CO)10, a (tmbp)-Mn2(CO)6 complex is formed where tmbp acts as an eight electron donor.

Notes: (E)-8,8′-(Ethene-1,2-diyl)bis(5-tert-butyl[2.2]metacyclo-phane) (2) was obtained from a McMurry reaction of 5-tert-butyl-8-formyl[2.2]metacyclophane (1). Irradiation of 2 with a high-pressure mercury lamp gave the corresponding (Z) isomer 3. X-ray crystallographic analyses of 2 and 3 show a certain degree of twisting of the bond connecting the meta-cyclophane unit and the central π system due to steric crowding. UV spectra of 2 and 3 and of the charge-transfer complexes [2/TCNE] and [3/TCNE] allow for a discussion of π-π interaction between the central stilbene subunit and the outer benzene rings of the metacyclophane units. Bis[2.2]meta-cyclophanes 2 and 3 reacted regioselectively with hexacar-bonylchromium on the outer benzene rings giving 1:1 and 1:2 complexes 9-14 with tricarbonylchromium. No 1:3 and 1:4 complexes formed due to steric restrictions. Analysis of UV spectral data of the complexed [2.2]metacyclophanes was performed for an indication of π-π interactions in the complexes.

Notes: Here we report on investigations that have revealed for the first time that the Cs+ ion templates the same metal germanium sulfide open-framework as (CH3)4N+ (TMA+), and that metal complexing agents enhance crystal size by at least two orders of magnitude. The synthesis, structures and thermal properties of Cs2FeGe4S10 ·× H2O and TMA2FeGe4S10 are also described. Both have 3D zinc blende-type open-framework structures. These materials have the same connectivity as TMA2MnGe4S10. The tetrahedral sites in the lattice are alternately substituted by pseudo-tetrahedral Fe2+ and adamantanoid Ge4S104- building blocks, covalently linked together by Fe(μ-S)Ge bridge bonds, to give a tetragonal unit cell. The charge-balance of the anionic framework [Fe-Ge4S10]2- is maintained by either Cs+ or TMA+ ions in the cavity spaces. Synthesis of these materials demonstrates an interesting example of a self-assembly process in which a 3D framework is built from molecular precursors. Water adsorption-desorption cycling from room temperature to 200 °C reveals framework flexibility between larger and smaller tetragonal unit cell 14 isotypes. The compound TMA2FeGe4S10 is stable in nitrogen at 350 °C and under vacuum at 450 °C. The corresponding temperatures for Cs2FeGe4S10 are 530 °C and 630°C; it is stable on cooling to room temperature under vacuum, and after subsequent exposure to air. Six hundred thirty degrees celsius is the highest recorded temperature at which the integrity of a non-oxide framework has been maintained. The framework stability and flexibility of “all-inorganic” Cs2FeGe4S10 provides an encouraging example for researchers interested in developing sulfide-based framework materials with practical applications.

Notes: The reaction of InBr/InBr3 or InBr/BrIn[(CH2)3NMe2]2 with the transition metal dimers [L(CO)nM]2 {L = CO, Cp, C5H4[(CH2)2NMe2]; M = Fe, Co, Ni; n = 1-3} in THF or dioxane gives in almost quantitative yield the transition metal indium complexes L(CO)nM—InBr2(Do) (Do = THF, NC7H13) and L(CO)nM—In[(CH2)3NMe2](Br) respectively. The new compounds were characterized by elemental analysis, infrared v(CO) spectroscopy, NMR, and mass spectrometry. An X-ray single crystal structure determination of (η5-C5H5)(CO)-Ni-InBr2(NC7H13) (1a) revealed a short Ni-In bond of 246.3(1) pm.

Notes: Neutral molybdenum and tungsten complexes containing only one η4-coordinated 1-oxa-1,3-diene ligand are obtained diastereospecifically from the reaction of the corresponding dicarbonylbis(oxadiene) complexes with bidentate donor ligands capable of forming five-membered ring chelates. Thus, dicarbonylbis[η4-(R)-(+)-pinocarvone]metal complexes react with 1,2-bis(dimethylphosphanyl)ethane (dmpe) or N,N,N′,N′-tetramethylethylenediamine (tmeda) to give the mono(oxadiene) compounds 1 - 4 in 45-95% yield. The molecular structure of the dmpe-tungsten complex 3 was determined by X-ray structural analysis Spectroscopic data indicate that an effective transfer of electron density from the donor atoms occurs. This is also reflected in a decreased reactivity of the carbonyl ligands in the mono(oxadiene) complexes towards nucleophilic alkylation. As a result, the selectivity in the alkylation (a formal “Umpolung” reaction) of anionic intermediates generated from 2 and methyllithium with carbon electrophiles is greatly improved, allowing access to alkylation products, e.g. 5, that are otherwise difficult to obtain.

Notes: One tripeptide, five tetrapeptides, and one pentapeptide, all containing His-Xn-His sequences and being blocked at the N and C termini with acyl and amide functions, respectively, were synthesized by solid-phase methods. With one exception their reaction with various zinc salts led to the precipitation of 1:1 (zinc/peptide) complexes. Analytically pure compounds were obtained from zinc tetrafluoroborate and His-Gly-His (1), from zinc chloride (resp. bromide) and His-Gly -Gly-His (2), His-Ala-Gly-His (3), His-Leu-Gly-His (4), His-Pro-Gly-His (5), and His-Pro-Asn-His (6) as well as from zinc sulfate and His-Leu-Gly-His (4) and His-Ala-Pro-Gly-His (7). 1H-NMR data, when available, indicate the coordination of both histidine units to zinc in all cases. The low solubility of the complexes points to their polymeric nature. The only 1:2 (zinc/peptide) complex in this series was obtained from zinc perchlorate and His-Gly-Gly-His (2). An EXAFS study revealed that it contains zinc symmetrically coordinated by four histidine imidazole ligands. Based on the available information it is proposed that all complexes are one-dimensional polymers containg [-Zn-His-Xn-His-Zn-]x backbones.

Notes: The reaction of [IrCl(C8H14)2]2 (2) with SbiPr3 in the presence of H2 yields the dihydridoiridium(III) complex cis,mer-[IrH2Cl(SbiPr3)3] (3) which on treatment with CO and with HC≡CR (R = Ph, CO2Me) affords the octahedral derivatives [IrH2Cl(CO)(SbiPr3)2] (4) and [IrHCl(C≡CR)(SbiPr3)3] (5, 6), respectively. The stibane ligand trans to hydride in 5 and 6 is rather labile and, therefore, 5 and 6 react with pyridine to give [IrHCl(C≡CR)(py)(SbiPr3)2] (7, 8). Five-coordinate bis-(stibane)iridium(I) complexes [IrCl(C2H4)2(SbR3)2] (10-12) were prepared from [IrCl(C2H4)2]2 (9) and four equiv. of SbR3 (R = iPr, Me, Ph). The X-ray crystal structural analysis of 10 reveals a distorted trigonal-bipyramidal geometry around the metal center with one stibane ligand and the two olefinic ligands in the equatorial plane. Compound 10 reacts with NaC5H5 to yield [C5H5Ir(C2H4)(SbiPr3)] (13) and with different alkynes by partial or complete displacement of the ethene ligands to give trans-[IrCl(PhC≡CPh)(SbiPr3)2] (14), [IrHCl(C≡CTol)(C2H4)(SbiPr3)2] (15), and trans-[IrCl-{=C=C(SiMe3)R}(SbiPr3)2] (16, 17), respectively.

Notes: On the Silaethene tBu2Si=C(SiMe3)2, and the Structure and Reactivity of Its [4 + 2] Cycloadduct with Ph2C=OFrom tBu2SiF—CLi(SiMe3)2 by LiF elimination only Me2Si= C(SiMe3)(SiMetBu2) (1b) instead of tBu2Si=C(SiMe3)2 (1a) is isolated. With benzophenone, silaethene 1b (from its THF adduct 1b · THF) forms at -78 °C a yellow [4 + 2] cycloadduct (5) and a colorless [2 + 2] cycloadduct (6). With increasing temperature 5 transforms into 6, and 6 transforms -more slowly - into the yellow [4 + 2] cycloadduct (7) of 1a and Ph2CO. It follows from this that the migration equilibrium 1a ⇄ 1b really exists. The structure of 7 shows a planar —O—CPh=C6H5-framework with the cycloadded atoms Si and C from -tBu2Si—C(SiMe3)2- located above the plane. The =C6H5—C bond (1.62 Å) is exceptionally long. 7 is a source for 1a which is trapped by acetone (formation of an ene product) and by benzaldehyde [formation of a [2 + 2] cycloadduct, unstable against cycloreversion into PhHC=C(SiMe3)2 and tBu2SiO-containing substances]. Reaction of 7 with trimethylsilyl azide, less reactive than acetone or benzaldehyde, leads - by way of 1a which transforms into 1b - to a trapping product of 1b (formation of a [3 + 2] cycloadduct, unstable against transformation into (RMe2Si)(Me3Si)CN2 with R = (Me3Si)2N, or cycloreversion into (tBu2MeSi)(Me3Si)CN2 and Me2SiNSiMe3-containing substances). Reaction of 1b or 1b · THF with acetone leads only to an ene reaction product of 1b. This means, that only undetectable amounts of 1a or 1a · THF are in equilibrium with 1b or 1b · THF. A minor substance which is shown by NMR at low temperatures besides 1b or 1b · THF is interpreted as a rotamer of 1b or 1b · THF.

Notes: Imidazole Derivatives, XVII. - Synthesis and Properties of Dichloro(1,3-dimethyl-2-imidazol-2-ylidenimino)phosphane - a Methylenamino Substituent with Uncommon Donor PropertiesDichloro(1,3-dimethyl-2-imidazol-2-ylidenimino)phosphane (5) is obtained from 1,3-dimethyl-2,3-dihydro-2-trimethylsilyliminoimidazole (4) and PCl3 in almost quantitative yield. Strong PN-π interaction (5B) is revealed by its X-ray structure analysis [P(1)-N(1) 1.579(2) Å]. AlCI3 causes chloride abstraction to give the cationic cyclophosphazane 8 identified by NMR spectroscopy.

Notes: The aminal Me2NCH2NMe2 is doubly metalated by LitBu to give LiCH2N(Me)CH2N(Me)CH2Li, which reacts with chlorosilanes to afford the respective silylated species, including the six-membered heterocycle Me2SiCH2N(Me)CH2N(Me)-CH2 and the spiroheterocycle Si[CH2N(Me)CH2N(Me)CH2]2.

Notes: Molecules containing dimetallated hydrocarbyl groupings are of great chemical interest[1-3]. These groupings often represent intermediates in important catalytic processes[4]. Recently, we have shown that substituted dimetallated olefins can be formed by alkyne insertion into the metal-metal bonds of certain dinuclear complexes[2,5]. Complexes having dimetallated hydrocarbyl groups combined with heteroatoms are quite rare[6]. Herein is described the formation of a dimetallathioimidate grouping by the insertion of an organic isothiocyanates into an unsupported metal-metal bond. Organic isothiocyanates are useful reagents in organic synthesis[7], but the organometallic chemistry of these molecules is not yet well developed[8].

Notes: In the presence of Lewis acidic derivatives of group 13 elements, phosphaalkynes 7 undergo spirocyclotrimerization with incorporation of the corresponding Lewis acids to form 10a-f. Scope and limitations of this novel cyclooligomerization process are examined. Starting from the spirocyclotrimer 10a reaction with the Lewis base dimethyl sulfoxide, we have in hand for the first time a method for the selective generation of two isomeric triphospha Dewar benzene derivatives (18, 19). Both can be trapped efficiently by further reaction with the phosphaalkyne to furnish the two novel phosphaalkyne cyclotetramers 20 and 21, both still possessing a phosphorus-carbon double bond. In the case of 21, further functionalization of the phosphaalkene unit is possible by [3 + 2] cycloaddition with a nitrile oxide (→ 23).

Notes: It is shown that supermolecules with a tetrahedral symmetry and appropriate side-chains exhibit liquid-crystalline phase behaviour. The use of an optimised hydrosylation reaction allows for the synthesis of materials that have four mesogenic groups attached to a siloxane core, where the conformation and the configuration are unambiguous. The materials show low glass transition temperatures and, depending on the spacer length, complex liquid-crystalline morphologies.

Notes: In search of water soluble transition metal complexes with sulfur dominated coordination spheres that model key reactions of nitrogenases, the benzenedithiol derivatives ‘CO2HS2’-H2 (1) and ‘CO2Me-S2’-H2 (2) were synthesized as precursors for multidentate sulfur ligands. The template alkylation of 2 by C2H4Br2 at [Fe(CO)2] fragments yielded a mixture of two diastereomeric C2 symmetrical [Fe(CO)2(‘CO2Me-S4’)] complexes (4a and 4b), which were separated by crystallization. The hydrolysis of the mixture of the diastereomers 4a and 4b led to the isomerically pure tetradentate thioether thiol ligand ‘CO2Me-S4’-H2 (5) proving the regioselectivity of the template alkylation of the asymmetrical dithiol 2. The C1 symmetrical [Fe(‘CO2Me-S2’)2]2- anion is an intermediate of the template alkylation and was isolated as (AsPh4)2 [Fe(‘CO2Me-S2’2] (11), 4a, 5 and 11 were characterized by X-ray structural analysis. Saponification of the methyl ester groups of 5 yielded ‘CO2H-S4’-H2 (7). Treatment of 7 with FeCl2 · 4 H2O in the presence of CO and LiOMe gave a mixture of two C2 symmetrical and water soluble diastereomers of Li2[Fe(CO)2(‘CO2-S4’)] (8). Upon treatment with [RuCl2 (PPh3)3] 7 yielded isomerically pure [Ru(PPh3)2-(‘CO2H-S4’)] (9). 9 also exhibits C2 symmetry and could be reversibly deprotonated to form the water soluble complex K2[Ru(PPh3)2 (‘CO2-S4’)] (10). Treatment of (NBu4)2 (‘CO2MeS2’) with “Ru(NO)Cl3” led to isomerically pure (NBu4)[Ru(NO)(‘CO2Me-S2’)2] (12).

Notes: Carbon and oxygen chemical shift tensors for bridging and terminal carbonyl ligands in Fe2(CO)9 and Rh6(CO)16 were calculated by sum-over-states density-functional perturbation theory (SOS-DFPT). Agreement with experimental 13C shift tensors is excellent, and 17O shift tensors are predicted. The reduced anisotropy values of the shift tensors for the bridging compared to terminal carbonyl ligands are due to large deshielding contributions to δ33 from non-bonding or bridge-bonding orbitals. Comparison to recent computational results for a series of unusual piano-stool and bent-sandwich group-4 complexes is made. The electronic structures of the clusters are discussed by using plots of electron localization functions (ELF). Bonding electrons within the Rh6 cluster are mainly localized on the unbridged octahedral faces. This leads to a heterocubane-like arrangement of ELF maxima above all octahedral faces (four bridging CO ligands, four M-M 3-center-bonding maxima), in analogy to previous results for B6H62-.

Notes: The amidoaluminium hydride complexes [(Me3Si)2NA1(X)(H) · NMe3], X = H (1), Cl (2), were prepared by the metallation of bis(trimethylsilyl)amine by Al(X)(H)2 · NMe3 (X = H and Cl). The molecular structure of 2 as a monomeric Lewis base adduct with four-coordinate aluminium centres and terminal amido groups was confirmed by X-ray crystal structure determination. We also find that bis(trimethylsilyl)amine forms a thermally stable adduct of alane, (Me3Si)2N(H) · AlH3 (3). Ab initio molecular orbital calculations on the possible products arising from these reactions yielding 1 and 2 revealed that the amido-bridged species, {(μ-H2N)Al(X)H}2 (X = H and Cl), are favoured over nitrogen donor Lewis base adduct formation, H2NAl(X)(H) · NH3 (X = H and Cl), and then chloro-bridged, {H2NAl(μ-X)(H)}2, (X = Cl only), and hydrido-bridged species, {H2NAl(X)(μ-H)}2 (X = H and Cl).

Notes: The 31P chemical shift tensors of the transition-metal phosphane complexes M(CO)5PX3 (M = Cr, Mo, W; X = H, CH3, F, Cl) were studied using a combination of density functional theory and ab initio effective-core potentials. The calculated isotropic shifts agree well with experimental results both for the free ligands and for the complexes, with the largest deviations occuring for the tungsten complexes. A breakdown of the computed phosphorus shielding tensors into contributions from localized molecular orbitals (LMOs) indicates that the positive coordination shift of PH3 and P(CH3)3 is due to increased paramagnetic contributions from the phosphorus lone pair (P-M s̰ bonding) LMO to δ⊥. A similar increase of this contribution is found for PF3 and PCl3. However, for PCl3 complexes these terms are overcompensated by a reduction in the paramagnetic contributions from the P-Cl bonds and by shielding contributions from metal-centered orbitals. This results in a negative overall coordiantion shift. A partial cancellation is found with P(CH3)3 and with PF3. The changes in the 31P-shift tensors of the same phosphane ligands upon protonation are qualitatively and quantitatively very different from the coordination shifts and do not provide good models for the latter.

Notes: After a brief review of previous work the results of the metathesis reaction between Ni(dme)Br2 and R2P(O)NR′Li [R = tBu, iPr, Ph; R′ = Et, Pr, iPr, (±)-sBu, tBu, tPen, Cy, Ph, (-)-α-methylbenzyl = Mb, 1-adamantyl = Ad] are reported. Complex formation occurred only with lithiated amides of tert-butylphosphinic acid, and bischelates [tBu2P(O)NR′]2Ni were obtained when R′ = sBu, Mb, tPen, Ad (1d - g). With R′ = Et, Pr bischelation was incomplete. Vis spectroscopy showed the paramagnetic compounds 1d - f to be planar in the solid state but tetrahedral in solution. 1g is tetrahedral in both phases. The planar structure of 1f was confirmed by X-ray single-crystal analysis (monoclinic, space group P21/n). The magnetic moments μeff of 1d, e, g are ca. 3.2-3.5 μB in both phases and the Curie-Weiss law is obeyed in the range 293-183 K. The same is valid for dissolved 1f. The μeff values of solid 1f are however, strongly temperature-dependent, varying from 1.38 to 0.55 μB (300-90 K). NMR data (31P, 1H, 13C) are reported. Obviously, a favorable combination of electronic and steric factors of substituents R and R′ produces with ligands [R2P(O)NR′]- the donor quality necessary for bischelation as well as the singular field strength required for the formation of planar paramagnetic species. As the combination of paramagnetism and planarity is bound to the solid state, lattice energy effects may be finally decisive for this unique constellation of tetracoordinated NiII complexes.

Notes: Treatment of [Mo(CO)6] with Hmamnp (2-acetamido-7-methyl-1,8-naphthyridine) in diglyme at 100°C affords the mononuclear complex [Mo(CO)4(Hmamnp)] 1, an intermediate product on the reaction pathway to tetrasubstituted species of the type [Mo2L4]. A disubstituted intermediate product cis-[Mo2(mphamnp)2(OAc)2] 2 (Hmphamnp) (2-acetamido-5-methyl-7-phenyl-1,8-naphthyridine) may be isolated from the reaction of [Mo2(OAc)4] with mphamnp- in THF. The relative stabilisation of such products is a result of the steric demands of the coplanar 2-acetamido substituents. 2 and the tetrasubstituted complexes trans-[Mo2(mbznnp)4] 3 (Hmbznnp = 2-benzylamino-7-methyl-1,8-naphthyridine), cis-[Mo2(mphonp)4] 4, and trans-[Mo2(mphonp)4] 5 (Hmphonp = 5-methyl-7-phenyl-1,8-naphthyridin-2-one) all exhibit the electronically prefered μ-N1,X2 bridging mode. Steric effects are responsible for the isolation of the unusual cis isomer 4.

Notes: Treatment of (PP2)IrCl[PP2 = tBuP(CH2CH2CH2PPh2)2] with an equimolar quantity of CpM(CO)3H (M = Mo, W) or with HCl in THF resulted in smooth protonation of the d8 substrate producing [(PP2)Ir(H)Cl]X {X- = [CpMo(CO)3]- (1), [CpW(CO)3]- (2), Cl- (3)}. Combination of (PP2)IrCl and CpM(CO)3H in a 2:1 stoichiometry gave (PP2)Ir(H)Cl2 (7) together with [(PP2)IrCO]-[Mo(CO)3Cp] (8) or [(PP2)IrCO][W(CO)3Cp] (9). The rhodium analogues (PP2)Rh(H)Cl2 (4), [(PP2)RhCO][Mo(CO)3Cp] (5), and [(PP2)RhCO][W(CO)3Cp] (6) were obtained similarly from (PP2)RhCl and CpM(CO)3H. Structural assignments for [(PP2)Ir(H)Cl]+ and (PP2)M′(H)Cl2 (M′ = Rh, Ir) as diastereomers in which the hydrido ligand and the tBu substituent on the central phosphorus atom are located on the same side or on opposite sides of the PP2 reference plane of the meridionally bound tBuP(CH2CH2CH2PPh2)2 ligand are made on the basis of (i) correlations with known structures and reactivities of similar [(RP(CH2CH2CH2PR′2)2M′(H)Cl]+ cations and (ii) an X-ray structure determination of 4. The crystal structure analysis of a [(PP2)RhCO]+ salt, closely related to 5/6 and 8/9, [(PP2)Rh(CO)][OCO2H] (10), demonstrates that in the solid state the four-coordinate [(PP2)RhCO]+ cation and its counterion exist as essentially charge-neutralized Rh⃛O-contacted ion pairs, two of which are linked by O—H⃛O bridges to centrosymmetric dimers. Ion pairing was also observed by IR spectroscopy for THF solutions of metalates 5/6 and 8/9.

Notes: Chiral Tripodal Ligands Bearing a Phosphite Donor Group: Synthesis and Coordination ChemistryThe mechanism of the reaction of epichlorohydrine (H-CH2Cl) (1) with lithium phosphides is analysed. A neighbouring-group mechanism has been found to be the essential driving force in this reaction. Monophosphanyl alcohols such as HOCH(CH2P(Ph)2)(CH2Cl) (2) and epoxides (Ph)2PCH2- (3) are characterized as intermediates. The mechanism leads to a rapid one-pot method for the synthesis of chiral racemic as well as enantiomerically pure bis(phosphanyl) alcohols HOCH(CH2PR2)(CH2PR2′) (4). The resulting bis(phosphanyl) alcohols 4 react easily with X2PCl (X = Cl; Ph; or X2 = 1,2-ethanedioxy-2,2′-biphenyldiyldioxy-) to yield the mixed donor group tripodal ligands X2POCH(CH2PR2)(CH2PR′2) (5, 6) containing both phosphite, phosphinite or phosphorodichloridite and phosphane donor groups. The identity of these compounds were proved by 1H-, 31P- and 13C-NMR spectroscopy, mass spectra, microanalysis as well as X-ray analysis. The coordination capabilities of these novel ligands are demonstrated by the synthesis and characterization of a (cyclooctadiene)rhodium complex {[(5c)Rh(I)COD]PF6} (7) of the ligand 5c, exhibiting the typical hetero-bicyclooctane tripod metal cage of this type of tripod complexes.

Notes: The electrochemical preparation of nanostructured titanium clusters is possible by using a titanium sacrificial anode as the metal source and tetrabutylammonium bromide in THF as the electrolyte and stabilizer. Transmission electron microscopy shows the presence of spherical 3.0-nm-sized particles. THF solutions of these Ti clusters induce olefin-forming McMurry-type coupling of aldehydes and ketones.

Notes: Bis(dichlorosilyl)amine reacts in chloroform solution with 2-picoline to give H3SiCl, H2SiCl2, and HSiCl3, whereas with 3-picoline the two hypervalent silicon compounds H2SiCl2-(3pic)2 and [H2Si(3pic)4]Cl2 · 4 CHCl3 containing hexacoordinated Si atoms are formed. These complexes are in a chemical equilibrium with each other in chloroform solution, from which crystals of [H2Si(3pic)4]Cl2 · 4 CHCl3 could be isolated. The crystal structure of the latter was determined by single-crystal X-ray diffraction. The complex can be regarded as an “contact ion trio” of [H2Si(3pic)4]2+ and two Cl- ions. The N-Si bond lengths, r(Si-N) = 196.9(3) and 197.5(3) pm, are similar to those found in neutral hexacoordinated Si complexes. The data obtained from a 1H1H ROESY experiment suggest that dissolution has no significant impact on the molecular structure of [H2Si(3pic)4]Cl2 · 4 CHCl3.

Notes: Concentrated solutions of the ozonides LiO3 and NaO3 in anhydrous liquid ammonia were obtained for the first time by using an ion exchange reaction that starts from CsO3. No solid LiO3 or NaO3 can be precipitated. Upon removal of the solvent, the ozonide anion oxidises ammonia, resulting in the precipitation of LiOH and NaOH, respectively. This behaviour is in sharp contrast to that of solutions of KO3, RbO3 and CsO3. Proof of the existence of LiO3 and NaO3 in the solutions is provided by complexation of the cations with cryptands, which leads to solid (Li[2.1.1])O3 and (Na[2.2.2])O3. Crystal structure analysis shows that these are ionic solids containing the V-shaped O3- anion.

Notes: The first high yield preparation of non π-stabilized bis(lithio-methyl)silanes was performed by the reductive cleavage of C-S bonds with electron transfer reagents. Bis[(phenylthio)-methyl]silanes synthesized by the reaction of dichlorosilanes with [(phenylthio)methyl]lithium were transformed to the corresponding bis(lithiomethyl)silanes 7 by reaction with lithium naphthalenide (LiC10H8) or lithium p,p′-di-tert-butyl-biphenylide (LiDBB) as an electron transfer reagent and were characterized by their reaction with Bu3SnCl. The C-S bonds of bis[(phenylthio)methyl]silanes can be cleaved selectively making possible the introduction of two different groups. - The silicon atom plays a central role in the reactivity of the presented structural types. The bis(lithiomethyl)silanes are used as new building blocks for the preparation of organosilanes, Si-H-functionalized organosilanes, and 1,3-disilacyclobutanes containing SiCH2Si structural units.

Notes: 1,3-Bis(5′-methyl-2,2′-bipyrid-5-yl)propane (3) can be synthesized by a two-step procedure starting from 3-picoline (1). In a spontaneous self-assembly process 3 forms the binuclear triple-stranded meso-helicate [(3)3Fe2][PF6]4 on addition of iron(II) salts. The (Λ,Δ) structure can be shown by symmetry considerations based on NMR spectroscopy and is due to the conformational restrictions of the [CH2]3 spacer.

Notes: Di-tert-butylmethylsilylamide reacts with n-BuLi to give the tetrameric lithium di-tert-butylmethylsilylamide 1. Reactions of lithium (di-tert-butylmethylsilyl)amide 1 with SiF4 give the mono- (2), bis- (3), tris- (4), and tetrakis- (5) -[(di-tert-butylmethylsilyl)amino]silanes. Lithiated 3 reacts with Me3SiCl to form (di-tert-butylmethylsilyl-trimethylsilyl)amino-(di-tert-butylmethylsilyl)amino-difluorosilane (6); the 1,3-diaza-2,4-disilacyclobutane 7 is obtained by LiF elimination. The lithium derivative of 6 (compound 8) crystallizes with formation of a (SiFNLi) four-membered ring system. The 19F-NMR spectrum proves that the Li-F bond fluctuates in solution. Reactions of 1 with (Me3Si)2C(SiF3)2 afford different products (9, 10) by controlling the reaction sequence. An excess of 1 reacts to give a four-membered CSi2N ring system, the 1-(di-tert-butylmethylsilyl)-2,4-bis-[(di-tert-butylmethylsilyl)-amino]-2,4-difluoro-3-bis(trimethylsilyl)-1-aza-2,4-disila-cyclobutane (9), disubstitution with formation of bis[(di-tert-butylmethylsilyl)aminodifluorosilyl]bis(trimethylsilyl)methane (10) occurs in a molar ratio of 2:1. The cyclodisilazane 11 is obtained from dilithiated 10 in an intramolecular interconversion reaction. The crystal structures of 1, 8, 9, and 11 are reported.

Notes: The syntheses of oxotitanium(IV) meso-tetrakis(2,3,4,5,6-pentafluorophenyl)porphyrinate O=Ti(TPPF20) (1), oxotitanium(IV) meso-tetrakis(2,6-difluorophenyl)porphyrinate O=Ti-(TPPF8) (3), and oxotitanium(IV) meso-tetrakis(2,6-dichlorophenyl)porphyrinate O=Ti(TPPCl8) (5) from titanium tetrachloride and the corresponding porphine are described. The structure of 1 was determined by single-crystal X-ray diffraction. The reaction of oxotitanium porphyrinates with aqueous hydrogen peroxide leads to the corresponding light-sensitive peroxotitanium(IV) complexes: Ti(O2)(TPPF20) (2), Ti(O2)-(TPPF8) (4), Ti(O2)(TPPCl8) (6). All complexes are efficient and stable photosensitizers for the generation of singlet oxygen.

Notes: Methoxy-bis[tris(trimethylsilyl)silyl]methane (4), the first compound bearing two hypersilyl groups at a carbon atom, was synthesized by the reaction of tris(trimethylsilyl)silyllithium with dichloromethyl methyl ether. As a byproduct of the reaction, 1,2-dimethoxy-1,2-bis[tris(trimethylsilyl)silyl]-ethane (5) could be identified. Possible pathways leading to 4 and 5 are discussed. The structure of 4, elucidated by an X-ray crystal structure analysis, is characterized by tremendous distortions of the molecular skeleton due to the spatial demand of the two extended hemispherical (Me3Si)3Si groups. For example, the central Si-C-Si angle is widened to 132.7°, the trimethylsilyl groups of the two hypersilyl substituents are pressed together to give an average Si-Si-Si angle of 105.6°, and the methoxy carbon atom and the nearest neighboring trimethylsilyl carbon atom approach to a distance of 3.25 Å, i.e. approx. 19% less than the sum of the van der Waals radii of two methyl groups.

Notes: Intramolecularly Stabilized Metal Amides: 2-(Dimethylaminomethyl)pyrrolyl Complexes of Titanium(III), Vanadium(III), Chromium(III), Cobalt(II) and Nickel(II)By the metallation of 2-(dimethylaminomethyl)pyrrol (HL) with butyllithium the lithium pyrrolide LiL (1) was obtained. The reactions of 1 with TiBr3 · 3 THF, VBr3 · 3 THF, CrBr3 · 3 THF, CoBr2 · 2 THF, and NiBr2 · 1.67 THF result in the formation of the 2-(dimethylaminomethyl)pyrrolyl complexes of type ML3 (2-4), and ML2 (5, 6), respectively. The structures of these new compounds are discussed on the basis of magnetic and visible absorption measurements. An X-ray crystal structure determination of 4 reveals a strongly distorted octahedral environment of the chromium atom with facial arrangement of the ligands.

Notes: Metal π Complexes of Benzene Derivatives, 50. - Arylboranes as Sandwich Ligands: Preparation of [(iPrO)2B(η6-Ph)]2M and [Mes2B(η6-Ph)]2M (M = V, Cr). Redox Properties and EPR Study of M(d5) Neutral Complexes and Boron-Centered Radical AnionsBis(η6-arene)metal complexes bearing peripheral boryl substituents have been prepared by means of metal-atom ligand-vapor cocondensation leading to [(iPrO)2B-η6-C6H5]2Cr (7) and [(iPrO)2B-η6-C6H5]2V (8) as well as by lithiation and subsequent reaction with Mes2BF with formation of [Mes2B-η6-C6H5]2Cr (11) and [Mes2B-η6-C6H5]2V (12). According to the NMR spectra, rotation about the η-C-BR2 bonds in 7 and 11 is free at 25°C, restrictions setting in at -85°C. The neutral radicals 8• and 12• have been studied by EPR spectroscopy: despite of the profound difference in the electron-accepting properties of the groups (iPrO)2B- and Mes2B, the hyperfine coupling constants a(51V) differ by 5% only; the extent of perturbation of the electronic structure manifests itself more clearly in the g tensor, which is tetragonal for 8 but orthorhombic for 12, the degeneracy of the LUMO's e1g being raised in the latter. Cyclovoltammetry on 11 exhibits reversible oxidation as well as reduction processes. Reduction which, according to EPR, is ligand-centered, occurs in two steps which are separated by the redox splitting ΔE1/2 = 570 mV. This value, which is a measure of electronic communication between the two Mes2B groups, lies between those of 1,4-bis(dimesitylboryl)benzene (δE1/2 = 690 mV) and 4,4′-bis(dimesitylboryl)biphenyl (ΔE1/2 = 270 mV). The EPR spectrum of the radical anion 11-• reveals hyperfine coupling to one boron nucleus of a magnitude very similar to that of the free ligand radical anion Mes2BC6H5-•. Therefore, reduction of 11 is ligand-centered, and an intramolecular electron exchange between the boron centers is slow on the EPR time scale. As inferred from the observation of the hyperfine interactions a(53Cr) and a(1H), oxidation of 11 is metal-centered; relative to parent bis(η6-benzene)chromium (9), the two Mes2B groups cause an anodic shift of 290 mV for the couple 11+/0. The radical cations 11+• are prone to protodeborylation, in this aspect resembling the respective silyl derivatives.

Notes: Metal π Complexes of Benzene Derivatives, 49. - Halfsandwich Complexes of Trimesitylborane Mes3B: Synthesis and Structure of Mes2[B(η6-Mes)Cr(CO)3], MesB[η6-MesCr(CO)3]2, and B[η6-MesCr(CO)3]3. Redox Behavior and Questions of Intramolecular InteractionReactions of trimesitylborane (15) with hexacarbonylchromium (16), under varying conditions of stoichiometry and duration, afford the halfsandwich complexes 15[Cr(CO)3] = 17, 15[Cr(CO)3]2 = 18 and 15[Cr(CO)3]3 = 19, which have been characterized by X-ray structure analysis. As for the free ligand 15, the propeller shape of the complexes 17-19 induces chirality; the respective unit cells contain both enantiomers. The steric demand of the Cr(CO)3 fragments causes significant structural changes of the Mes3B unit: in 17 and 18 the bond lengths B-C are increased and the C-B-C bond angles in the reference plane ER1, which is spanned by the three carbon atoms bonded to boron, deviate from 120°; the largest differences was observed for 18. Coordination of Cr(CO)3 fragments to 15 leads to increased dihedral angles between the reference plane ER1 and the mesityl planes; the values of 50.1° for 15 and 61.8° for 19 are representative. Because of the lower symmetry within 17 and 18, the dihedral angles differ; a maximum of 71.1°, relative to the reference plane, is assumed by the noncoordinated ring of 18. The main objective of the study of 17-19 relates to the question of intermetallic communication between moieties separated by sp2-hybridized boron. According to IR data, interaction between the Cr(CO)3 units appears to be minimal. Cyclovo-Itammetry is more revealing: boron-centered reduction, which occurs at -1.94 V for 15, involves anodic shifts E1/2 (0/-) of + 0.24 ± 0.04 V per Cr(CO)3 unit for 17, 18 and 19. This trend is surprising since with increasing degree of coordination the dihedral angles also increase and, therefore, conjugation between the B(2pz) orbital and the mesitylene π systems decreases. Consequently, the redox shifts reflect competition between conjugative and inductive effects, the latter exceeding the former. Subsequent reduction to the dianions 172- -192- is quasi-reversible at -50°C. Chromium-centered oxidation in the +1 V region yields CV waves that fail to reveal resolved redox splitting δE1/2 between subsequent redox steps. However, based on the current ip(0/-) of one electron reduction, the peak currents for the oxidations of 17, 18 and 19 represent one-, two- and three-electron processes, respectively. Although these waves deviate from ideal reversibility, a gradual shift to more positive potentials and an increase in peak separation is discernible. From these features, the value δE1/2 ≤ 70 mV for subsequent oxidation processes at 18 and 19 may be derived as a crude estimate, attesting to weak interaction between the Cr(CO)3 moieties. The radical anions 15-•, 17-•, 18-• and 19-• were generated electrochemically and studied by means of EPR spectroscopy. The hyperfine coupling constants a(11B) increase in the order 17-• 〈 18-• ≤ 15-• 〈 19-•, which again demonstrates the action of stereoelectronic effects. Proton hyperfine coupling is resolved only for the radical anion 15-• of the free ligand. This implies that for the complex radical anions 17-• -19-•, due to the larger angles between the B(2pz) orbital and the z axes of the mesitylene π systems, conjugation Blarr;mesitylene is diminished. The UV/Vis spectra of 17-19 exhibit MLCT bands, which, relative to (η6-C6H6)Cr(CO)3 (λ = 317 nm), show large bathochrome shifts [λ (17) = 458 nm]. The additional shifts effected by introducing a second and third Cr(CO)3 unit are small however [λ (18) = 491 nm, λ (19) = 516 nm]. The energies ΔEop of the MLCT transitions may be compared to the differences ΔEcv = E1/2 (+/0, metal-centered) - E1/2(0/-, ligand-centered), the quantity δE = ΔEop - ΔEcv representing χout the outer-sphere reorganisation energy. For 17-19, the value δE = 0.18 ± 0.1 eV is thus obtained. Interestingly, for p-Me2NC6H4BMes2 δE = 0.29 eV has been reported, suggesting a similarity between a Me2N substituent and a Cr(CO)3 fragment bound to tris(aryl)borane.

Notes: The cyclopentadienyl complexes [C5H5Rh(RC≡CR′)(SbiPr3)] (5-8), which were prepared from trans-[RhCl-(RC≡CR′)(SbiPr3)2] (1-4) and NaC5H5 and which contain a labile Rh-SbiPr3 bond, reacted with CO and CNR″ (R″ = Me, tBu) to give the carbonyl and isocyanide derivatives [C5H5Rh(RC≡CR′)(CO)] (9-11) and [C5H5Rh(RC≡CR′)-(CNR″)] (12-16), respectively. On treatment of 12 (R = R′ = Ph; R″ = Me) with SbiPr3, the metallacyclobutene complex [C5H5Rh{κ2(C,C}-C( = NMe)CPh=CPh}(SbiPr3)] (17) was formed; it reacts with excess CNMe or CNtBu to yield the metallacyclopentenes [C5H5Rh{κ2(C,C)-C(=NMe)CPh=CPhC-(=NR)}(CNR)] (18, 19). Similar compounds 20-23 containing a five-membered RhC4 metallacycle were prepared either from [C5H5Rh(RC≡CR′)(SbiPr3)] (7, 8) or [C5H5Rh-(PhC≡CPh)(CNtBu)] (14) and excess isocyanide. The crystal and molecular structures of 17 and 18 (R = Me) have been determined.

Notes: The [(SePPh2)2N]- ligand 1c forms stable tris(chelates) with the SbIII, BiIII, and InIII ions. The crystal and molecular structures of the resulting compounds 3, 4, and 5 were determined by X-ray diffractometry. The coordination geometry around the metal centers can be described as a distorted octahedron. This feature and the results obtained by comparing the structures with their sulfur and oxygen analogs lead us to conclude that in both SbIII and BiIII compounds the arrangement around the metals suggests a stereochemically nonactive electron lone pair.

Notes: Treatment of 5,10,15,20-tetra-4-pyridylporphyrin [(TPyP)H2] with europium(III) or gadolinium(III) acetylacetonate [Ln(acac)3 · nH2O] (Ln = Eu, Gd) in 1,2,4-trichlorobenzene produced Ln(acac)(TPyP), which reacted with dilithium phthalocyaninate [Li2(Pc)] to give Li[Ln(Pc)(TPyP)] in moderate yields. Upon exposure to air, solutions of these compounds converted slowly to the corresponding neutral complexes Ln(Pc)(TPyP). The new compounds were spectroscopically characterized.

Notes: The reduction of the complex [(η5-C5H4)-ansa-(η5-C5H4)]TiCl2 with magnesium in the presence of Me3SiC2-SiMe3 in THF at room temperature gives the ansa-titanocone alkyne complex [(η5-C5H4)-ansa-(η5-C5H4)]Ti(η2-Me3SiC2-SiMe3) (ansa = Me2Si-O-SiMe2, 1). The similar pyridine-stabilized zirconium complexes could be obtained by analogous reactions and addition of pyridine: [(η5-C5H4)-ansa-(η5-C5H4)]Zr(L)(η2-Me3SiC2SiMe3) (ansa = Me2Si-O-SiMe2, L = pyridine: 2; ansa = SiMe2, L = pyridine: 3). All complexes were characterized by spectroscopic methods. An X-ray structure determination of complex 3 was conducted, and the data were compared to those of the complexes rac-(EB-HI)Zr(L)(η2-Me3SiC2SiMe3) [L = (S)-(-)-nicotine: 6, EBHI = ethylenebis(tetrahydroindenyl)] and Cp2Zr(py)(Me3SiC2-SiMe3).

Notes: The thermal and/or photochemical reaction of [Cp‴Co(CO)2] (1), Cp‴ = 1,2,4-tBu3C5H2, with white phosphorus, P4, gives besides [(Cp‴Co)2 (P2)2] (2) the trinuclear complexes [(Cp‴Co)3P8] (3) and [(Cp‴Co)3P12] (4), the Pn ligands of which form P5-P3 and P5-P7 skeletons, structural motifs, which formally can be derived from Hittorf's phosphorus. The X-ray crystal structure analysis of 3 confirmed its P5-P3 framework.

Notes: The structure of lithium sorbate (C6H7LiO2) was determined by single-crystal X-ray diffraction. It may be divided into organic and inorganic layers. The ionic part of the structure consists of a two-dimensional network of corner- and edge-sharing lithium oxotetrahedra, a structural pattern already known from other lithium carboxylates. Irradiation of the substance with X-rays or its thermal treatment results in the formation of a polymer exhibiting ionic conductivity at higher temperatures. Due to the rather large distances between potentially reactive atoms the polymerization results in a structural breakdown. Nevertheless, during the solid-state polymerization preferred orientations of building units are partially preserved. The probable course of the polymerization and the structure of the resulting polymer are discussed.

Notes: Tripod Ligands with Neopentane Frame and two Different Donor Groups CH3C(CH2PPh2)2(CH2SR): Synthesis, Structure, Redox Chemistry, and Spectroscopy of the Complexes tripodM{ortho-(X)(Y)C6H4}Prof. Dr. Jörn Müller zum 60. Geburtstag gewidmet.Neopentane-based tripod ligands CH3C(CH2PPh2)2(CH2Z) (Z = SBn, SH, S-) form pentacoordinate compounds [tripodM{ortho(X)(Y)C6H4}]m 1-4 with ortho-phenylene-bridged coligands (X)(Y)C6H4 (X, Y = O-, S-, NH-) and Co(II), Co(III), Fe(II), or Fe(III) as the metal centers. The structures of these complexes are very similar to those observed for CH3C(CH2PPh2)3 as the tripod ligand. The redox potentials, however, for the corresponding one-electron oxidation and reduction processes are highly affected by the change in the tripod donor groups. Both potentials are shifted by a maximum of 700 mV upon replacement of a PPh2 donor group by a sulfur-centered donor with the difference between the potential of the oxidation step and the potential of the reduction step staying almost constant for the whole series of compounds. This difference of around 1.7 eV nicely corresponds to the energy of the HOMO-LUMO chargetransfer bands observed around 2 eV for all of the compounds. It may be inferred therefore that both observations (electron spectroscopy and cyclic voltammetry) refer in a similar way to the HOMO-LUMO gap of the compounds. It is shown that the formation of [tripodCo(III){ortho-(NH)2C6H4}]+(BF4-) from ortho-phenylenediamine as the source of the coligand involves precoordination of the amine ligand followed by deprotonation of the coordinated ligand. The capability of the tripodCo(II) template to form five-coordinate compounds with diamines is further corroborated by the characterization of [tripodCo(en)]2+ (52+). In addition to the standard analytical data, EPR, UV/Vis, cyclovoltammetric data and X-ray structure analyses are presented where appropriate.

Notes: Metal Complexes of Biologically Important Ligands, LXXXIXPart LXXXVIII: Ref.[1]. .  -  Oxidative Addition of Electrophilic Derivatives of α-Amino Acids to Platinum(II) and Cobalt(I) Complexes: α-Transition-Metallated Amino Acids Herrn Professor Dr. Hans Georg von Schnering zum 65. Geburtstag gewidmet.The addition of methyl α-bromohippurate to PtMe2(bipy) gives the α-metallated amino acid derivative (bipy)-Me2(Br)PtC(H)(NHCOPh)(CO2Me) as a mixture of isomers 1a, b of which the trans adduct 1a was characterized by X-ray diffraction. Methyl α-bromohippurate and N-Boc-O-tosylserine methyl ester are added to [Co(py)(DH)]- (DH = dimethylglyoxime, diphenylglyoxime) to give cobalt(III) complexes 2-5 with a cobalt-carbon bond.

Notes: The bisquaternary ammonium ozonides Me3N+(CH2)n +NMe3(O3-)2 with n = 3, 4, 6 (1, 2, 3), Me3N+(CH2)3+NMe3(O3-)2 · 3 NH3 (1a), Me3N+(p-Ph)+NMe3(O3-)2 (4) and Me3N+(p-Ph)+NMe3(O3-)2 · NH3 (4a) were obtained in quantitative yields by cation exchange starting from CsO3. The compounds 1a and 3 have been studied by single crystal X-ray analysis. The influence of C-H…O and N-H…O hydrogen bonds on the bond length and the bond angle of the ozonide anion is discussed; earlier results are included. The difference between the two bond lengths within the O3- ion [137.4(3) pm and 129.5(3) pm] in 1a is unexpectedly large. Thermal stabilities determined by DTA/TG methods range from 24-83°C.

Notes: [Co{HB(C2H2N3)3}2] reacts with an excess of CuCl2 in hot water with formation of ∞2[Cu2Cl2{μ3-HB(C2H2N3)3}2 · 2 H2O] (7) or ∞3{[Cu2{μ4-HB(C2H2N3)3} (μ-OH)2]Cl · 6 H2O} (8), depending on the reaction time. 8 can also be obtained from [Cu{HB(C2H2N3)3}2] and CuCl2 in aqueous ammonia. The 2-D double-layer-type coordination polymer 7 crystallizes in the orthorhombic space group P212121. The two different Cu(II) centers in the lattice are distinguished only be the direction of the Jahn-Teller distortion. The following corresponding distances for the CuClN5 coordination sphere were found Cu1/Cu2-Cl = 2.572(2)/2.328(2), Cu1/Cu2-N = 2.585(5)/2.077(4); 2.000(4)/1.979(5); 2.100(5)/2.734(5); 2.005(4)/1.994(4); 2.024(5)/2.369(5). In the 3-D coordination polymer 8 one of the two different Cu centers is chelated by the three endodentate nitrogen donors, while the other Cu center is coordinated by three exodentate nitrogen atoms. The coordination sphere is completed in both cases by two hydroxo bridges to symmetry-related Cu centers. The metal-ligand connectivity creates infinite channels with helical walls which contain the solvated chloride anions.

Notes: Ba14InP11 was prepared from the elements in a sealed stainless steel ampoule at 1345 K. The compound is black, brittle and very sensitive to air and moisture. Ba14InP11 crystallises in the tetragonal Ca14AlSb11 type (space group I41/acd, No. 142; a = 17.097 (2) Å, c, = 8, Pearson code tI208). The structure contains isolated P3-, linear [P3]7- and tetrahedral [InP4]9- anions. The X-ray structure analysis and the vibrational spectra show that the [P3]7- polyanion is strongly asymmetric with d(P-P) = 2.28 Å and 4.10 Å, corresponding to a [P2]4- dumbbell weakly coupled to a single p3- anion. The tetraphosphidoindate(III) anion [InP4]9- is slightly compressed along the 4 axis, with bond lenght d(In-P) = 2.71 Å. It is shown that the structure is hierarchically related to that of Cu2O, with two interpenetrating frameworks, in which the O and Cu atoms are replaced by condensed [InP4/2] tetrahedron and [BaP4P2/2] octahedra, respectively. Both frameworks are meso configured, containing alternate R and S fragments. The other Ba cations envelop the P6 octahedra and P3 triads forming condensed cubes, tetragonal antiprisms and bicapped trigonal prisms. Therefore, the structure also forms a heterogeneous framework of centred PBa8/2tap tetragonal antiprisms and BaBa8/2cub cubes, consisting of two interpenetrating enantiomorphic nets (R and S) similar to those in the cubic phase RhBi4.

Notes: The substituted 6-hydroxy-trans-3-hexenoic acids 2a and 2b are prepared by an organometallic template reaction involving a sequence of CC coupling reactions between a CO2 equivalent, butadiene, and 3-cyclopenten-1-one or 3,4-diphenyl-3-cyclopenten-1-one, respectively. In the crystal 2a assembles to form an infinite ribbon-type structure, exhibiting an alternating array of 12 and 18 atom-containing loops. The former are each constructed by an alternating CO2H/OH/CO2H/OH sequence, originating from four different monomeric units, that are linked together by means of hydrogen bonds. Two complementary ribbons of 2a are connected by van der Waals interactions to form staples that constitute the microscopic building blocks of the true (2a)n structure in the crystal. Stacks of cyclopentene π bonds are oriented inside the columnar structure of 2a. Acid 2b also forms a related ribbon-like assembly in the solid state. Here the bulky 3,4-diphenylcyclopentadienylidene moieties are oriented laterally at the ribbons, and van-der-Waals interactions with adjacent ribbons construct a three-dimensional hydroxyhexenoic acid network.

Notes: Barium bis[bis(trimethylsily)amide] metalates bis(isopropyldimethylsilyl)phosphane (1) to yield nearly quantitatively the corresponding barium bis[bis(isopropyldimethylsilyl)phosphanide] (3). This compound shows a temperature-dependent monomer-dimer equilibrium in toluene solution. Both the isomers were characterized by X-ray crystal structure analyses. The monomeric derivatives precipitate as a tetrakis(tetrahydrofuran) complex with a P-Ba-P bond angle of 139.9°. The barium atoms of the monocyclic, centrosymmetric dimer are pentacoordinated by two tetrahydrofuran molecules, one terminal and two bridging phosphanide ligands. The endo- and exocyclic Ba-P distances with values of 332 and 316 pm, respectively, lie within the characteristic range.

Notes: The metal complexes (E,E)-[{diethyl 2,2′-[1,2-phenylenebis(iminomethylidyne)]bis[3-oxobutanoato]}(2-)-N,N′,O3,O3′]manganese (Mn1a), [3,3′]-[1,2-phenylenebis(iminomethylidyne)bis(2,4-pentanedionato)(2-)-N,N′,O2,O2′]manganese (Mn1b), and (Z,Z)-[diethyl 3,3′-(1,2-phenylenediimino)bis(2-cyano-2-propenoato)](2-)-N3,N3′,O1,O1′]manganese (Mn1c) were sythesised and the oxygenation of these complexes was investigated by gas volumetry. All complexes except Mn1c are able to take up oxygen but with different magnitudes. The catalytic activity of the Mn, Co, and Fe complexes of the ligands 1a and 1c and (E,E)-[{diethyl 2,2′-[1,2-ethylenebis(iminomethylidyne)]bis[3-oxobutanoato]} (2-)N,N′,O3,O3′] iron (Fe1d) and [diethyl (all-E)-5,14-dihydro-6,17-dimethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine-7,16-dicarboxylato)(2-)-N5,N9,N14,N18]iron (Fe2a) has been compared with respect to the oxidation of hydroquinone by molecular oxygen. The results are interpreted with the aid of electrochemical properties, Lewis acidities, and other relevant factors. However, no simple relationship between the catalytic activity and the other factors could be found.

Notes: Some dithioxophosphoranes 3 stabilized by intramolecular coordination with a dialkylamino group were prepared, and their structures were analyzed by X-ray crystallography involving [2,4-di-tert-butyl-6-(isopropylmethylamino)phenyl]- (3c), {2,4-di-tert-butyl-6-[(dimethylamino)methyl]phenyl}- (3f), and {2,4-di-tert-butyl-6-[2-(dimethylamino)-1,1-dimethylethyl]phenyl}dithioxophosphorane (3h). The bond between the phosphorus atom and the aromatic ring is flexible and the angle narrows with decreasing ring size of the intramolecular coordination. The 31P-NMR signals are shifted to higher field with increasing ring size of the intramolecular coordination or strength of coordination. Similarly, the corresponding diselenoxophosphoranes 4 were prepared. Both their 31P- and 77Se-NMR signals are shifted to higher field with increasing contribution of intramolecular coordination.

Notes: The cationic iron (alkynyl)aminocarbene complexes [Cp(CO)2Fe(C(NHR)C≡CSiMe3][PF6], (R = C6H5, p-CH3C6H4) 1 derived from aromatic amines smoothly react with cyclopentadiene in dichloromethane to yield the cycloadducts 2. No reaction was observed for complexes derived from sterically demanding aliphatic amines, like L-alanine tert-butyl ester. For comparison, the alkynyl-substituted acyl iron compounds Cp(CO)2Fe(C=O)C≡C̊ (R = SiMe3, C6H5) 3 were investigated, requiring TiCl4 catalysis to undergo the cycloaddition reaction. The structures of the cycloadducts 4 were determined by X-ray crystallography.

Notes: P-tertiary or amino-substituted 1-phosphanylnaphth-2-yl silyl ethers 3 are synthesized by stepwise reaction of lithium 1-lithio-2-naphtholate 1 with chlorophosphanes and ClSiMe3. The free phosphanylnaphthols 4 are prepared by alcoholysis. As established by characteristic coupling constants and X-ray structural analyses (of 3c, 4c), 3 exhibit in solution and in the solid state a cis-bisecting conformation, whereas 4 prefers the opposite trans-bisecting arrangement, allowing easy protonation and formation of chelate complexes. Substitution reactions of phosphanylnaphtholates 2 with Ph2PCl and formation of chelate complexes LNi-η5-Cp and L2Pd are described. Attempts to prepare secondary and primary phosphanylnaphthols failed because of facile cleavage of the P-C(naphthyl) bond in PH-substituted 1-phosphanylnaphth-2-ols.