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  • 1
    ISSN: 0009-2940
    Keywords: Iron and ruthenium complexes ; Water soluble complexes ; Sulfur ligands ; X-ray structure analyses ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    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).
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  • 2
    ISSN: 0009-2940
    Keywords: Labile ruthenium-sulfur complexes ; S2 Complexes ; Substitution reactions ; Ligand effects ; Structure-activity relationships ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to synthesize labile and well-soluble [Ru(L)(L')(“S4”)] complexes, [Ru(CI)2(DMSO)4] was treated With “S4”-Na2 (S42- = 1,2-bis(2-mercaptophenylthio)-ethane(2-1)] yielding [Ru(DMSO)2(“S4”)] (1 which contains two labile DMSO ligands. An X-ray structural analysis of 1, verifies that both DMSO ligands are coordinated via their S atoms. The reaction of 1 with small ligands such as PR3 (R = Et, nPr, nBu) or tetrahydrothiophene (THT) leads to substitution of both DMSO ligands yielding [Ru(PR3)2(“S4”)] (R = Et 3a, nPr 3b, nBu 3c) and [Ru(THT)2(“S4”] 2, respectively, while bulky phosphane ligands such as PCy3 and PiPr3 substitute one DMSO ligand to yield [Ru(DMSO)(PR3])(“S4”] (R = iPr 4a, Cy 4b). X-ray structural analyses of [Ru(PnPr3)2(“S4”)] · 0.5 MeOH (3b · 0.5 MeOH), [Ru(PnBu3)2(S4)} (3c), and [Ru(Pme3)2(“S4”)] (3d) confirm the pseudo-octahedral coordination of the Ru centers by four Sdonors and two cis P-donors and reveal close similarities bet ween the three complexes. Comparision of the structural parameters of 3b · 0.5 MeOH, 3c and 3d with those of [Ru(PPh3)2(“MeS, 4”)] [MeS4“2” = 1,2-bis(2-mercaptophenylthio)propane(2-1)] indicates that the inertness towards substitution of 3b · 0.5 MeOH, 3c and 3d as opposed to the substitution lability of [Ru(PPh3)2(,MeS4“)] is caused by the small cone angles of the alkyl phosphanes. In the DMSO/PCy3 complex 4b both coligands are labile, and which one is substituted depends on the size of the entering ligand. The reactions of 4b with PnR3 yield [Ru(DMSO)(PR3)('S4”)] (R = nPr 4c, nBu 4d) in contrast to the reaction with CO. PMe3, and SMe2 which give [Ru(CO)(Pcy3)(“S4”)] (5b), [Ru(P-Me3)(PCy3)(“S4”)] (6, and [Ru(SMe2)(PCy3)(“S4”)] (7, respectively. In an analogous manner, the CO complexes [Ru(CO(PR3)(“S4”)] (R = iPr 5a, nBu 5c) have been obtained by treatement of 4a and 4d with CO. The reactions of 4a and 4b with S8 yielded the readily soluble μ-S2 complexes [μ-S2[Ru(PR3)(“S4”)]2] (R - iPr 8a, Cy 8b). The spectroscopi9c data of complex 8b and its cyclic voltammogram, which exhibits four quasi-reversible redox waves, indicate a strong electronic coupling of the two [Ru(PCy3)(“S4”)] fragments via the μ-S2 bridge.
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  • 3
    ISSN: 0009-2940
    Keywords: Chirality ; Stereogenicity ; Diastereoselectivity ; Ligand stereospecificity ; Metal sulfur complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to investigate the stereochemistry of substitution reactions of chiral pseudo-octahedral complexes the chiral thioether-thiolate ligands ‘RS4’-H2 (= HSC6H4SCHRCH2-SC6H4SH) with R = CH3- (5), CH3(CH2)2- (6), HO(CH2)9- (7), and PhCH2- (8) were synthesized by template alkylation of Na2[Ni(‘S2’)2] [‘S2’2- = 1,2-benzenedithiolate(2-)] with 1,2-dibromoalkanes BrCHRCH2Br (R = CH3-, 1; R = CH3(CH2)2-, 2; R = HO(CH2)9-, 3; R = PhCH2-, 4) and isolated after hydrolyses. Reactions of ‘RS4’-H2 with [RuCl2(PPh3)3] or [Mo(O)2(acac)2] yielded [Ru(PPh3)2(‘RS4’)] (R = CH3-, 9; R = HO(CH2)9-, 10; R = PhCH2-, 11) and [Mo(O)2(‘MeS4’)] (12). [Ru(PPh3)2(‘MeS4’)] · 2 CH2Cl2 (9 · 2 CH2Cl2) and [Mo(O)2(‘MeS4’)] (12) were characterized by X-ray structure determination. In both complexes, the metal centers are surrounded pseudo-octahedrally by four sulfur donors of the ‘MeS4’ ligand and two cis coligands. The methyl substituent at the stereogenic C* atom of the C2 bridge of the ‘MeS4’ ligands assumes an equatorial position. In addition, the metal centers of these complexes are chirotopic and prostereogenic. Crystal data of 9 · 2 CH2Cl2 in comparison with [Ru(PBu3)2(‘S4’) 11-bis(2-mercaptophenylthio)-1-undecanolato(2-), ‘PhCH2S4’2-1,2-bis(2-mercaptophenylthio)-3-phenylpropanato(2-)] ] and those of 12 in comparison with [Mo(O)2(‘S4’)] show that distances and angles of the coordination cores are not influenced by the substituents on the C2 bridge. Reactions of the [Ru(PPh3)2(‘RS4’)] complexes (9-11) with the achiral substrates CO and PMe3, however, yielded diastereomers of [Ru(PPh3)(L)(‘RS4’)] (L = CO, R = CH3-, 13; L = CO, R = HO(CH2)9-, 14; L = CO, R = PhCH2-, 15; L = PMe3, R = CH3-, 16; L = PM R = HO(CH2)9-, 17; L = PMe3, R = PhCH2-, 18) in diastereomeric excesses between 60 and 82%. The diastereomer of [Ru(PPh3)CO)(‘MeS4’)] (13) which could be characterized by X-ray structure determination exhibits the CO ligand in trans position to the thioether donor which is bound to the stereogenic C* atom of the C2 bridge. Reaction of 9 · 2 CH2Cl2 with the optically pure bidentate diphosphine (+)-(S,S)-DIOP [= (+)-2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane] yielded 1:1 mixtures of two diastereomers of [Ru(DIOP)(‘MeS4’)] (19) one of which was separated in pure form by HPLC.
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  • 4
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Complexes with Sulfur Ligands. XLIV. Ruthenium(II) Complexes with the Sterically Demanding Thioether-thiolate Ligand ‚buS4‘2-(= 1,2-Bis(3,5-di(tertiarybutyl)-2-mercaptophenylthio) ethane (2-)) and PPh3, CO, PMe3, NH3, and N2H4 ColigandsThe coordination properties of the sterically demanding thioether-thiolate ligand ‘buS4’2- (= 1,2-Bis(3,5-di(tertiarybutyl)-2-mercaptophenylthio)ethane (2-)) towards Ruthenium were investigated. [Ru(PPh3)2 (‘buS4’)], 1, was obtained from [RuCl2(PPh3)3] and ‘buS4’—Li2. One PPh3 ligand in 1 is labile towards substitution and can be exchanged by L = CO (2), PMe3 (3), or NH3 (5) yielding [Ru(L)(PPh3)(‘buS4’)]. The PMe3 complex [Ru(PMe3)2(‘buS4’)], 4, is thermically inert as well as 2, 3, and [Ru(CO)2(‘buS4’)], 6, which was obtained from [RuCl2(CO)3THF] and ‘buS4’—Li2. Considering the thermical reaction inertness of 6, its fast reaction with N2H4 yielding [Ru(N2H4) (CO) (‘buS4’)], 7, is remarkable; the reaction probably takes place via 19e- intermediates. All ‘buS4’ complexes are better soluble in organic solvents than the corresponding [Ru(‘S4’)] parent compounds, their ν(CO)frequencies or 31PNMR shifts, however, are nearly identical, allowing the conclusion that the influence of the t-butyl groups is topological and not electronic. All now complexes were characterized by elemental analyses as well as IR, NMR, and mass spectroscopy.
    Notes: Die Koordinationseigenschaften des sterisch anspruchsvollen Thioether-Thiolat-Liganden ‚buS4‘2- (= 1,2-Bis(3,5-di(tertiärbutyl)-2-mercaptophenylthio)ethan (2-)) gegen-über Ruthenium wurden untersucht. Dabei wurde [Ru(PPh3)2(‚buS4‘)], 1, aus [RuCl2(PPh3)3] und ‚buS4‘—Li2 erhalten. Ein PPh3-Ligand in 1 ist substitutionslabil und kann durch L = CO (2), PMe3 (3 oder NH3 (5) unter Bildung von [Ru(L)(PPh3))(‚buS4‘)] ersetzt werden. Der zu 1 analoge PMe3-Komplex [Ru(PMe3)2(‚buS4‘)], 4, ist thermisch inert, ebenso wie 2, 3 und [Ru(CO)2(‚buS4‘)], 6, das aus [RuCl2 (CO)3THF] und, ‚buS4‘—Li2 erhalten wurde. In Anbetracht der thermischen Reaktionsträgheit von 6 ist seine rasche Reaktion mit N2H4 zu [Ru(N2H4)(CO)(‚buS4‘)], 7, bemerkenswert; die Reaktion verläuft wahrscheinlich über 19e--Zwischenstufen. Alle ‚buS4‘-Komplexe sind in organischen Lösungsmitteln besser löslich als ihre [Ru(‚S4‘)]-Stammverbindungen, n̈(CO)-Frequenzen oder 31P-Verschiebungen sind jedoch nahezu identisch, woraus auf einen topologischen, nicht aber elektronischen Einfluß der t-Butylgruppen geschlossen werden muß.Alle neuen Komplexe wurden elementaranalytisch sowie IR-, NMR- und massenspektroskopisch charakterisiert.
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  • 5
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Complexes with Sulfur Ligands. LIX. Reversible μ-Oxo-Linkage of [Mo(NO)(′S4′)]-Units: Hydrolysis of [Mo(X)(NO)(′S4′)] (X = Cl, Br, NMe2, NPMe3), leading to [μ-O{Mo(NO)(′S4′)}2] (′S4′2- = 2,3,8,9-Dibenzo-1,4,7,10-tetrathiadecane(2-))In order to investigate specific properties of transition metal sulfur complexes with the tetradentate ligand ′S42- = 2,3,8,9-Dibenzo-1,4,7,10-tetrathiadecane(2-), [μ-O{Mo(NO)(′S4′)}2], 1, was synthesized by hydrolysis of [Mo(X)(NO)(′S4′)] (X = Cl, Br, NMe2, NPMe3). 1 crystallizes as 1. THF in the triclinic space group P1 with Z = 2, a = 1066.7(6), b = 1442.4(4), c = 1547.0(5) pm, α = 65.01(2), β = 87.79(4), γ = 70.48(3)°, R = 0.065, Rw = 0.053. X-ray structure analysis shows both Mo centers to be pseudooctahedrally coordinated by two thiolato-S, two thioether-S, one nitrosyl-N and the bridging oxygen atom. The μ-oxo ligand acts as σ-μ donor ligand such that the Mo centers obtain a formal 18 electron configuration. Thus, according to the short Mo—O distance of 186.6(6) and 189.1(6) pm, the Mo(μ-o) bonds exhibit double bond character. X-ray studies prove one pair of enantiomers (RR/SS) in the solid state, whereas 13C-NMR spectroscopic results indicate the existence of two different diastereomers in solution. The mononuclear complex [Mo(CI)(NO)( ′S4 ′)], 2, was obtained by cleavage of 1 with gaseous HCI in a reversible reaction under retention of the stable [Mo(NO)(′S4 ′)]-fragments.
    Notes: Zur Untersuchung der spezifischen Eigenschaften von Übergangsmetall-Schwefelkomplexen mit dem vierzähnigen Liganden ′S4′2- = 2,3,8,9-Dibenzo-1,4,7,10-tetrathiadecan(2-) wurde [μ-O{Mo(NO)(′S4′)}2], 1, synthetisiert. Es entsteht bei der Hydrolyse von [Mo(X)(NO)(S4′)] (X = Cl, Br, NMe2, NPMe3). 1, kristallisiert als 1. THF in der triklinen Raum-gruppe P1 mit Z = 2, a = 1066,7(6), b = 1442,4(4) c = 1547,0(5) pm, α = 65,01(2), β = 87,79(4), γ = 70,48(3)°, R = 0,065, Rw = 0,053. Die Röntgenstrukturanalyse zeigt, daß beide Mo-Zentren pseudooktaedrisch von zwei Thiolat-S-, zwei Thioether-S-, einem Nitrosyl-N-Atom und dem verbrückenden O-Atom umgeben sind. Der μ-Oxo-Ligand fungiert als σ-π-Donor, so daß das Mo-Zentrum eine formale 18e-Konfiguration erhält. Die Mo(μ-O)-Bindungen (Mo—O: 186,6(6), 189,1(6) pm) weisen Doppelbindungscharakter auf. Die Röntgenstrukturanalyse beweist das Vorliegen eines RR/SS-Enantiomerenpaares im festen Zustand, wohingegen 13C-NMR-spektroskopische Ergebnisse die Existenz von zwei unterschiedlichen Isomeren in Lösung aufzeigen. Aus Umsetzung von 1 mit gasförmigem HCl resultiert in einer reversiblen Reaktion, unter Erhalt der stabilen [Mo(NO)(′S4′)]-Fragmente, der einkernige Komplex [Mo(Cl)(NO)(′S4′)], 2.
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