ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1520-6041
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stable Tetraazafulvalenes - Syntheses and ChemistryThe syntheses, properties and reactions are described for 1,3,6,7-tetrakis[arylamino]-1,4,5,8-tetraazafulvalenes and their vinylogous derivatives. First, the acylation of form- as well as acetamidine with bis-imidoylchlorides derived from oxalic acid 6 formed reactive cyclic intermediates which dimerized to tetraazafulvalenes 12 or bisvinylogous tetraazafulvalenes 14. Based on, a further synthesis was found using a cycloacylation reaction of amidines with imidoylchlorides 6 followed by prototropic migration of α-hydrogen. Thus, the vinylogous compound 15 and the phenylogous derivatives 16, 17 could be isolated in moderate up to good yields. Besides amidines, other derivatives of carboxylic acids as amides or thioamides could be transformed into corresponding tetraazafulvalenes 18-20. Due to their vicinal amino groups, alkylation and acylation reactions were studied. For example, the reaction with orthoformates yielded the ring fused products 24a,b which may be starting material for carbenes just as the cyclization product with thiophosgene 27. Treatment of tetraazafulvalenes with anhydrous iron-II salts or molybdenum hexacarbonyl yielded the deeply colored metal diazadiene complexes 33 and 34. Finally, reduction using metallic lithium and subsequent alkylation constitutes a convenient synthetic entry to heterocyclic analogues of stilbene 37.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0044-2313
    Keywords: Nickel(0) ; binuclear compounds ; functionalized alkynes ; supramolecular structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Binuclear Nickel(0) Alkyne Coordination Compounds - Correlation between Ligand Periphery and Supramolecular StructureReaction of Ni(cdt: 1,5,9-cyclododecatriene) with functionalized alkynes and subsequent reaction with ethylenediamines gives binuclear compounds of the type (diamine)Ni(μ-alkyne)Ni(alkyne). Compounds with alkyne-diols (N⁁N)Ni2(HOR1R2C—C≡C—CR1R2OH)2 show supramolecular structures in which two identical intramolecular and one intermolecular hydrogen bonds are realized. 1 and 2 (chelate ligand in each case N,N,N′,N′-tetramethylethylenediamine, TMEDA, in 1 R1 = R2 = Me, in 2 R1 = R2 = Et) polymer-like chains are built up by connecting the binuclear units. Via two intermolecular hydrogen bonds per organometallic unit in 1 and via one intermoleculare hydrogen bond in 2 the chains are connected to give double chains. By substitution of one methyl group of TMEDA by hydrogen (3: R1 = R2 = Me) a polymerlike network is produced by connecting the polymer-like chains.In compound 4 in which one of the methyl groups of TMEDA is substituted by CH2CH2NMe2 the polymer-like chains remain unconnected. In 5 (diamine = TMEDA, alkyne = (CH3)3C—C≡C—CMe2OH) one intermolecular hydrogen bond per organometallic unit is observed forming again polymer-like chains that are independent of each other.
    Notes: Durch Reaktion von Ni(cdt) (cdt: Cyclododeca-1,5,9-trien) mit funktionalisierten Alkinen und anschließender Umsetzung mit Ethylendiaminen erhält man binucleare Alkin-Nickel(0)-Verbindungen des Typs (diamin)Ni(μ-alkin)Ni(alkin). In Verbindungen mit Alkindiolen (N ⁁ N)Ni2(HOR1R2C—C≡C—CR1R2OH)2 werden supramolekulare Strukturen aufgebaut, die jeweils zwei gleichartige intramolekulare und eine intermolekulare Wasserstoffbrückenbindung aufweisen. In 1 und 2 (Chelatligand jeweils N,N,N′,N′-Tetramethylethylendiamin, TMEDA, in 1 R1 = R2 = Me, in 2 R1 = R2 = Et) bilden sich durch Verknüpfung der binuklearen Einheiten polymere Stränge, die in 1 durch zwei und in 2 durch eine Wasserstoffbrückenbindung pro Organometalleinheit zu Doppelsträngen verknüpft werden. Ersatz einer Methylgruppe in TMEDA durch Wasserstoff (3: R1 = R2 = Me) bewirkt, daß die polymeren Stränge zu einem polymeren Netzwerk verknüpft werden. In Verbindung 4 (R1 = R2 = Me), in der im TMEDA eine Methylgruppe durch CH2CH2NMe2 ersetzt ist, bleiben die zu 1-3 analogen polymeren Stränge untereinander unverknüpft.In 5 (Diamin = TMEDA, Alkin = (CH3)3C—C≡C—CMe2OH) wird pro Organometalleinheit eine intermolekulare Wasserstoffbrückenbindung gebildet, was ebenfalls zu voneinander unabhängigen polymeren Strängen führt.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0044-2313
    Keywords: Copper(I) ; 1-azadienes ; oxidation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Copper(I) Complexes with 1-Azadiene Chelate Ligands and Their Reaction with OxygenThe reaction of the bidendate 1-azadiene ligands Me2N—(CH2)n—N=CH—CH=CH—Ph with CuX results in the formation of the dimeric compounds [ACuX]2 and [BCuX]2 (A: n = 2, B: n = 3, X: I, Cl). The structure of complex 1 [ACuI]2 was determined by X-ray crystal structure analysis. 1 consists of two tetrahedrally coordinated Cu atoms connected by two iodo bridges. (Cu—Cu bond length: 261 pm).The ligand Me—N(CH2CH2N=CH—CH=CH—Ph)2 (C) reacts with CuX to form the monomeric complexes [CCuX] (5: X=I, 6: X=Cl). The crystal structure of 5 shows that the ligand acts as a tridendate ligand. The bond lengths of the CuN(sp2) bonds are significantly shorter than the Cu—N(sp3) distance.Reacting the podand-type ligands N(CH2CH2—N=CH—R)3 (D: R=Ph, E: R=-CH=CH—Ph) with CuX yields the ionic complexes 7 [DCu][CuCl2] and 8 [ECu][CuCl2]. 7 was characterized by X-ray analysis which confirmed that D acts as a four-dendate podand ligand.The compounds 1-8 are unreactive towards CO2 but take up O2 even at deep temperatures. At -78°C the orange-red complex 4 [BCuCl]2 reacts with O2 in CH2Cl2 to form a deep violet solution, but the primary product of the oxidation could not be isolated. It reacts at room temperature to form the green complex 9 [μ-Cl, μ-OH][BCuCl]2. The X-ray structure analysis of 9 confirms that a dimeric CuII complex is formed in which both a chloro- and a hydroxo group are bridging the monomeric units. The CuII centers exhibit a distorted tetragonal-pyramidal coordination.The pathway of the reaction with O2 will be discussed.
    Notes: Die Reaktion der zweizähligen 1-Azadienliganden Me2N—(CH2)n—N=CH—CH=CH—Ph mit CuX führt zu den dimeren Komplexen [ACuX]2 and [BCuX]2 (A: n = 2, B: n = 3, X: I, Cl). Die Struktur des Komplexes 1 [ACuI]2 wurde durch Kristallstrukturanalyse bestimmt. 1 enthält zwei tetraedrisch koordinierte Cu-Atome, die über zwei Iodobrücken miteinander verknüpft sind Cu—Cu-Bindungslänge: (261 pm).Der Ligand Me—N(CH2CH2N=CH—CH=CH—Ph)2 (C) reagiert mit CuX unter Bildung der monomeren Komplexe [CCuX] (5: X = I, 6: X=Cl). Die Kristallstruktur von 5 zeigt, daß der Ligand dreizählig koordiniert. Die Bindungslängen der Cu—N(sp2)-Bindungen sind signifikant kleiner als der Cu—N-(sp3)-Abstand.Die Reaktion der Podand-Liganden N(CH2CH2—N=CH—R)3 (D: R=Ph, E: R=-CH=CH—Ph) mit CuX führt zu den ionischen Komplexen 7 [DCu][CuCl2] bzw. 8 [ECu][CuCl2]. 7 wurde durch Röntgenstrukturanalyse charakterisiert, die ausweist, daß D als vierzähliger Ligand fungiert.Die Komplexe 1-8 sind gegenüber CO2 nicht reaktiv, nehmen aber O2 schon bei tiefen Temperaturen auf. Bei -78°C reagiert der orangerote Komplex 4 [BCuCl]2 mit O2 in CH2Cl2 zu einer tiefvioletten Lösung, das Primärprodukt der Oxidation konnte jedoch nicht isoliert werden. Es reagiert bei Raumtemperatur zu dem grünen Komplex 9 [μ-Cl, μ-OH][BCuCl]2. Die Kristallstrukturanalyse belegt, daß ein dimerer CuII-Komplex gebildet wird, in dem eine Chloro- und eine Hydroxobrücke die Monomereinheiten verbrücken. Die CuII-Zentren weisen eine verzerrt tetragonal-pyramidale Koordination auf.Der Reaktionsweg der Umsetzung mit O2 wird diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 0009-2940
    Keywords: Titanocenes ; Alkynyl ligands ; Titanium complexes ; Nickel complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Reactivity of {(η5-C5H4SiMe3)2Ti(C≡CPh)2}Ni(CO)The synthesis and reactivity of {(η5-C5H4SiMe3)2Ti(C≡CPh)2}Ni(CO) (6) is described. (η5-C5H4SiMe3)2Ti(C≡CPh)2 (1a) reacts with equimolar amounts of Ni(CO)4 (5) to afford the dinuclear complex {(η5-C5H4SiMe3)2Ti(C≡CPh)2}Ni(CO) (6) in 95% yield. In 6 both phenylethynyl units are η2-side-on-coordinated to the Ni(CO) moiety. When 6 is treated with HX or X2 (X = Cl, Br) the Ti-C(alkynyl) σ bond is cleaved, and the corresponding titanocene dihalides (η5-C5H4SiMe3)2TiX2 (7) are formed. With PRR′2 [8a: R = R′ = OMe; 8b: R = C = CPh, R′ = Ph; 8c: R = Ph, R′ = C≡CPh] 6 reacts by substitution of the nickel-bonded carbonyl ligand to form {(η5-C5H4SiMe3)2Ti(C≡CPh2}Ni(PRR'2) (9). The reactivity of 9b, which contains a noncoordinated phenylethynyl unit, has been investigated by using Co2(CO)8 (10) and Fe2-(CO)9 (13). With 10 the compounds {η5-C5H4SiMe3)2Ti(C≡CPh)2}Ni(CO) (6), [μ-(η2-Ph2PC≡CPh)]Co2(CO)6 (11) and {[μ-(η2-Ph2PC≡CPh)]Co2(CO)5}2 (12) can be obtained. Complex 11 yields upon heating by decarbonylation and dimerization the six-membered cyclic compound 12. Whereas, the reaction of 9b with 13 affords {(η5-C5H4SiMe3)2Ti(C≡CPh)2}Ni(CO) (6) next to the dinuclear complex Fe2(CO)6-(μ-PPh2)[μ-(η1:η2-C≡CPh)] (14).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0009-2940
    Keywords: Nickel(0) ; Alkyne complexes ; Hydrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of (cdt)Ni (cdt: cyclododeca-1,5,9-triene) with 2 equivalents of 2-methyl-4-trimethylsilyl-3-butyn-2-ol leads to the selective formation of the homoleptic complex (alkyne)4Ni3 (compound 3), which can be isolated in excellent yields. The solid-state structure of 3 exhibits three Ni centers, forming a bent Ni3 chain connected by two bridging alkynes. The other two alkynes are terminally coordinated. Additionally, the trimeric units are stabilized by three intramolecular hydrogen bonds. Two intermolecular hydrogen bonds connect the trimeric units to form a polymer rope. According to the 13C- and 1H-NMR spectra in THF the structure of the complex 3 in solution is very similar to that in the solid state. The reaction of 3 with some alkynediols and with 2,5,5-trimethylhex-3-yn-2-ol affords compounds of the type (alkyne)2Ni. Cot (cot: 1,3,5,7-cyclooctatetraene) converts 3 into [(cot)Ni]2, which in turn reacts with 2,5-dimethylhex-3-yne-2,5-diol to form the dimeric complex (alkyne)2Ni2(cot) 6. X-ray analysis of 6 reveals a very symmetrical structure in which cot connects both Ni(0) centers at opposite sides of the ring system.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0009-2940
    Keywords: Lithium-(fluorosilyl)phosphanides ; Phosphanides, lithium-(fluorosilyl)(phosphanyl)- ; Silylidenephosphanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Evidence for a Structure-Reactivity Relationship of Crowded Substituted Lithium (Fluorosilyl)phosphanidesThe molecular structures and the reactivity of the new solvated lithium (fluorosilyl)phosphanides 1a, 2a, and 2b has been investigated. The unusual solid state structures of 1a and 2b are established by X-ray crystallography. Whereas the lithium centre in 1a is bound to phosphorus and solvated by three molecules of THF, the electronical saturation of the lithium centre in 2b is achieved by a Li—P bond, tridentate chelatization (fluorine, phosphorus, nitrogen), and the additional coordination of one molecule of THF. The trigonal-planar geometry at phosphorus in 1a is unprecedented for derivatives of this type and reflects the steric demand around the phosphorus and the possibility of πp/σ*sic hyperconjugation. The Si—P bond lengths [P—SiC(Phenyl) 2.186(2) and P—SiF 2.164(2) Å] are significantly shorter than in related pyramidally configurated derivatives (1b, c: P—SiC 2.21, P—SiF 2.18 Å). Both phosphorus atoms in 2b are pyramidally coordinated, but the intramolecular chelate coordination of the lithium centre causes much smaller bonding angles at the Si—P phosphorus atom [sum of bonding angles 238.4(2) (PSi), 312.5(1)° (PN)]. 1a as well as 2a, b show quite different reactivity as compared to 1b-d due to their unusual structures. Heating of solutions of 1a and 2a, b in toluene or hexane does not give the expected stable silylidenephosphanes (Si=P) by elimination of LiF. Instead, rearrangement reactions of the Si=P intermediates 6, 8 lead to the new heterocycles 5, 9. A single-crystal X-ray diffraction analysis of 5 has been performed. The Si2P2 cyclobutane ring is planar, and the NMe2 groups at the ring silicon atoms are cis-orientated.  -  Interestingly, 2b eliminates LiNiPr2 at 20°C in a kinetically controlled process to form the tetraphosphacyclobutane 7 as the major product. Presumably, the diphosphene 8 is an intermediate in this reaction.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...