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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1421-1428 
    ISSN: 1434-1948
    Keywords: Grid complexes ; Self-assembly ; Co ; Zn ; Coordination chemistry ; Bis(tridentate) ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tretrametallic [2 × 2] grid-type complexes 1-4 are formed by self-assembly of the bis(tridentate) ligands 5 and 6 with ZnII and CoII cations. They have been characterized by spectroscopic studies in solution as well as by crystal structure determination. The substituents in the central pyrimidine ring play an important role in terms of geometry and physical properties of the complexes. They induce an orthogonal orientation of the ligand in the complexes which is critical for the formation of ordered monolayers and extended self-organized arrays of grids. The physical properties of the complexes such as metal-metal interaction and π-π* stacking between the ligands may be modulated by changing these substituents.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 1292-1302 
    ISSN: 0947-6539
    Keywords: complexes with nitrogen ligands ; ruthenium complexes ; self-assembly ; supramolecular chemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of mono- and dimetallic complexes of rack type containing a dinucleating bis-tridentate ligand and RuII-2,2′:6′,2′-terpyridyl (tpy) sites were synthesised and characterised. The 1H NMR spectra of the dimetallic complexes were correlated to structural features, and the crystal structures of the dimetallic complexes were determined. They provide information about the way in which the central substitutent affects the overall shape of the racks and the relative disposition of the metal centres, measured by the pinching angle of the bis-tridentate ligand and the convergence angle of the ancillary tpy units. The latter demonstrates that a CH3 group yields the least bent complex and indicates how parallel the tpy units are. The dimetallic racks exhibit metal-metal interactions mediated by the bis-tridentate ligands as indicated by electrochemical and spectroscopic methods. The bridging-ligand π* orbital and the dπ metal orbital are stabilised by complexation of a second metal. The results obtained provide guidelines for the design of extended racks bearing several metal centres in a linear arrangement, which also represent potential components of molecular electronic devices.
    Additional Material: 14 Ill.
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  • 3
    ISSN: 0947-6539
    Keywords: clusters ; copper complexes ; selenium compounds ; structure elucidation ; sulfur compounds ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of copper(I) acetate with bis(trimethylsilyl)chalcogenides E-(SiMe3)2 (E = S, Se) in the presence of tertiary phosphines in organic solvents leads to the formation of chalcogenbridged copper clusters in crystalline form. In recent investigations, the following structures were isolated and characterised by X-ray crystallography: [Cu24S12-(PMeiPr2)12] (1), [Cu28S14(PtBu2Me)12] (2), [Cu50S25(PtBu2Me)16] (3), [Cu70Se35-(PtBu2Me)21] (4), [Cu31Se15(SeSiMe3)-(PtBu2Me)12] (5) and [Cu48Se24(PMe2-Ph)20] (6). The cluster cores of 1-6 have new structures or new structural characteristics and go some way towards providing an insight into the mechanisms of cluster formation reactions. With the help of the aforementioned compounds a number of structure principles that govern sulfur-and selenium-bridged copper clusters can be formulated.
    Additional Material: 9 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 99-104 
    ISSN: 0947-6539
    Keywords: bipyridines ; copper compounds ; selfassembly ; supramolecular chemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The newly synthesised ligand 2 combines binding components known to undergo specific and distinct self-assembly processes with Cu1 ions. It complexes Cu1 to form, in almost quantitative yield, a large inorganic architecture 1 made up from four ligand molecules and twelve metal ions. The structure of 1 was ascertained by X-ray radiocrystallography as well as by NMR spectroscopy and electrospray mass spectrometry. It consists of a macrocycle of nanometric dimension with an external diameter of 28 Å; the central cavity has a diameter of 11 Å, which contains four PF-6 anions as well as solvent molecules. The spontaneous formation of 1 results from a self-assembly process based on a “program” combining two assembly subroutines, each specific to one of the ligand subunits. Self-assembly through double or, more generally, multiple subroutines can be used to generate a wide variety of highly complex inorganic supramolecular architectures by combination of two or more assembly processes.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 1494-1498 
    ISSN: 0947-6539
    Keywords: arsenic ; cobalt ; density functional calculations ; structural elucidation ; Zintl anions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [As7(SiMe3)3] reacts with [(Cp*CoCl)2] to give black crystals of the ionic compound [(Cp*Co)3As6][CoCl4] (1). The cation [(Cp*Co)3As6]2+ consists of an As6 prism, with squares capped by [Cp*Co] fragments. When [(CptBuCoCl)2] is used instead of [(Cp*CoCl)2] in the reaction, dark red crystals of [(CptBuCo)3As6][CoCl3(thf)]2 (2) and green-black crystals of [(CptBuCo)2As4][Co3Cl8(thf)2] (3) can be obtained. The cation in 2 shows a structure very similar to that of 1. The [(CptBuCo)2As4]2+ cations in 3 can be described as a triple-decker sandwich complex with two [CptBuCo]+ fragments bridged by an As4 ligand. Density functional calculations reproduce the experimental data of 1 and 3 and allow an interpretation of molecular electronic structure and bonding in these and related compounds with As replaced by P and Co by Fe.
    Additional Material: 10 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 429-435 
    ISSN: 0947-6539
    Keywords: ab initio calculations ; chalcogen compounds ; copper clusters ; ligand stabilisation ; thermodynamics ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The results of ab initio calculations for the sulfur-bridged copper clusters [Cu2nSn(PR3)m] (n = 1-4, 6; m = 0, 2, 4, 6, 8; R=H, CH3) were compared with those of theoretical investigations of the selenium-containing analogues that have been recently reported. The theoretical work was carried out in order to find a possible explanation for the experimentally observed-different-properties of both cluster types. The structural principles turned out to be independent of the chalcogen, except the necessary shortening of the copper-chalcogen atomic distance that results from the formal substitution of sulfur for selenium. Comparison of the energetics of the sulfur- and selenium-containing compounds showed that it is necessary to discuss the influence of the tertiary phosphine ligands that protect the existing clusters from reaction to give the solids Cu2S and Cu2Se. However the results of the calculations suggest that the different thermodynamic data of the cluster core and the Cu—P bonds-at least if PH3 or PMe3 are taken into account-cannot be the only cause for the differences in the experimental behaviour. The responsibility rests rather with kinetic effects, such as the steric demand of the actual ligands or the activation energy of decomposition of the ligand shell during the cluster-forming reaction.
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  • 7
    ISSN: 0947-6539
    Keywords: crystal structure ; density functional calculations ; polyarsenido complexes ; polyphosphido complexes ; Zintl anions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Zintl anion P3-7 reacts with complexes of transition metal halides to form multinuclear metal phosphorus clusters. Reaction of Li3P7·3 DME with [FeCp(CO)2Br] or [NiCl2(PBu3)2] leads to the formation of [P7{FeCp(CO)2}3] (1) and [{Ni(PBu3)2}4P14] (2), respectively. X-ray structure determinations show that in 1 the P7 cage of Li3P7 remains intact but in 2 a P14 framework is formed by linkage of two norbornadiene-like P7 units. The P14 skeleton coordinates to four Ni(PBu3)2 groups. LiCp* and CoCl2 react with P7(SiMe3)3 to give [(Cp*Co)3-(P2)3] (3) with three Cp*Co groups bridged by P2 units. Reaction of FeCl2 and LiCp* with P7(SiMe3)3 yields [(Cp*Fe)3P6][FeCl3(thf)] (4) or [(Cp*Fe)3{n3-P3)Fe}P6] (5), depending on the reaction conditions. In 4 the structure of the Fe3P6 core of the [(Cp*Fe)3P6]+ cation is comparable to closo-B9H92-, while in 5 the Fe4P6 core does not obey the Wade rules. The unusual Co-As cluster [Co6As12(PEt2Ph)6] (6), prepared from K, As, and [CoCl2(PEt2-Ph)2], can be described as a Co6As6 heteroicosahedron linked to two Co3As3 octahedra by common Co3 faces. A theoretical treatment within the density functional approximation reproduces the experimental structures of 2 and 6 and allows an interpretation of molecular electronic structures. In 2 one finds P-P double bonds that are delocalized to some extent into vacant Ni AOs. For the cage compound 6 the Co 3 d AOs participate in cage bonding and 38 electrons can be assigned to cage bonds; this is in accord with the (2N + 2) rule for 18-atom cages but not with the usual electron counting rules.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 2085-2088 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Coordination of Boron in triptych-Boroxazolidine (Triethanolamine Borate) and its Addition Compound with Antimony PentachlorideAdditional spectroscopic measurements of B(OC2H4)3N (1) and of the newly prepared 1 : 1-adduct with antimony pentachloride confirm a pyramidal O3B—N-structure for 1 and a trigonal-planar BO3-structure for the adduct. The thermal decomposition of 1 yields B2O3 and some derivatives of morpholine.
    Notes: Ergänzende spektroskopische Untersuchungen an B(OC2H4)3N (1) und seinem neu hergestellten 1:1-Addukt mit Antimonpentachlorid bestätigten für 1 eine pyramidale O3B—N-Anordnung und wiesen für das Addukt eine trigonal-planare BO3-Anordnung nach. Die thermische Zersetzung von 1 bei 240° ergibt in der Hauptsache Bortrioxid und einige Morpholinderivate.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 177-187 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diphenyl(trimethylsilyl)phosphine as a Reagent for the Preparation of Acylphosphides resp. phosphino Derivatives of Dicarboxylic Acids and Squaric Acid.Some new diphenylphosphides resp. diphenylphosphino derivatives of dicarboxylic acids and squaric acid have been synthesized by the aid of diphenyl(trimethylsilyl)phosphine. Most of the compounds are coloured and sensitive to light. Their vibration spectra are discussed.
    Notes: Die Umsetzung von Acylchloriden mit Diphenyl(trimethylsilyl)phosphin bietet einen präparativen Weg zu Acyl-(diphenylphosphiden) bzw. Diphenylphosphinoderivaten. Auf diese Weise wurden diese Derivate von einigen Dicarbonsäuren und der Quadrasäure erhalten. Die Verbindungen sind zumeist farbig und lichtempfindlich. Ihre Schwingungsspektren werden diskutiert.
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  • 10
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of Derivatives fo 2,3-Bis(diphenylphosphino)maleic Anhydride as a Contribution to the Problem of Colour, Conjugation, and complex Formation of this Class of CompoundsDerivatives of 2,3-bis(diphenylphosphino)maleic anhydride containing S, C (as ) and N (as or ) as heteroatom within the ring system (3-6) are prepared from the corresponding 2,3-dichloro compounds with the aid of diphenyl(trimethylsilyl)phosphine. These new compounds form chelate complexes of the type Ni(CO)2. L, Cr(CO)4-L (7-14). Ligands and complexes are strongly coloured. The heteroatom of the maleic anhydride ring influences remarkably the corresponding absorption bands. The solvatochromic effect on the low wave number absorption band of the metal(O) complexes is examined. For comparison 2,3-bis(diphenylamino)-N-methylmaleimide (15) and two diphenylphosphino derivatives (16, 18) of 3,4-dichloro-5-methoxy-2(5H)-furanone are synthesized. The vc=c bands of the compounds are assigned. The observed shifts (up to 120 cm-1) and the dependence of the colour on the size of the conjugated system are discussed.
    Notes: Derivate des 2,3-Dichlormaleinsäure-anhydrids, die als Heteroatom im Fünfring S, C (als ) und N (als bzw. )enthalten, wurden mit Diphenyl(trimethylsilyl)phosphin in die jeweiligen 2,3-Bis(diphenylphosphino)-Derivate (3-6) übergeführt, die als zweizähnige Liganden zwei CO in den Carbonylen von Ni, Cr und Mo substituieren können (7-14). Die freien Liganden und ihre Metallcarbonyle sind intensiv farbig. Die entsprechenden Absorptionsbanden zeigen einen beträchtlichen Einfluß des Heteroatoms im Fünfring an. Weiterhin wurde die Solvatochromie der langwelligsten Absorptionsbande in den Metallcarbonylderivaten untersucht. Zu Vergleichszwecken wurden ferner 2,3-Bis(diphenylamino)-N-methylmaleinimid (15) und zwei Diphenyl-phosphinoderivate (16, 18) des 3,4-Dichlor-5-methoxy-2(5H)-furanons erstmals dargestellt. Die Zuordnung von vc=c ist nunmehr in allen diesen Verbindungen möglich. Ihre bis zu 120 cm-1 betragende Verschiebung und die Abhängigkeit der Farben der Verbindungen von der Ausdehnung des konjugierten Systems werden diskutiert.
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