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  • Nickel complexes  (2)
  • Osmium  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of the Tetradentate Thioether Amine and Thioether Thiolate Ligands ′tpS2(NH2)2′ and ′tpS4′-H2 and Some Representative Six-Coordinate Ruthenium and Osmium Complexes [′tpS2(NH2)2′ =1,2-Bis(2-aminophenylthio)phenylene; ′tpS4′2- = 1,2-Bis(2-mercaptophenylthio)phenylene(2-)] (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 333-339 
    Details
    ISSN: 1434-1948
    Keywords: Cleavage reactions ; C-S cleavage ; Ligand synthesis ; Osmium ; Ruthenium ; S ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In search of a tetradentate thioether thiolate ligand that is more stable toward reductive C-S bond cleavage than the parent ligand ′S4′-H2 [′S4′-H2 = 1,2-bis(2-mercaptophenylthio)ethane], the novel tris-phenylene ligand ′tpS4′-H2 (3) [′tpS4′-H2 = 1,2-bis(2-mercaptophenylthio)phenylene] was synthesized via the nitro and amine compounds ′tpS2(NO2)2′ (1) and ′tpS2(NH2)2′ (2). The coordination of ′tpS4′2- to ruthenium centers resulted in the formation of six-coordinate [Ru(L)(PR3)(′tpS4′)] complexes (R = Et, L = PEt34; R = Ph, L = PPh35, CO 6, DMSO 7). The X-ray structure analyses of 4 and 6 revealed that the thiolate donors occupy trans positions; consequently the ′tpS4′2- ligand coordinates in the same way as the ′S4′2- ligand. The stability of the ′tpS4′2- ligand toward reductive C-S cleavage reactions was shown by the synthesis of [Os(PEt3)2(′tpS4′)] (8). In contrast to [Os(PEt3)2(′S4′)], 8 is stable for unlimited periods of time. The X-ray structure analysis of [Ru(Cl)2(PPh3)(′tpS2(NH2)2′)] (9) demonstrates that the potentially tetradentate ligand ′tpS2(NH2)2′ coordinates in 9 through three donors leaving one NH2 donor dangling.
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis, Structures, and Reactions of Sulfur-Rich Nickel and Platinum Complexes with [MS3] and [MNS2] Cores (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1715-1725 
    Details
    ISSN: 1434-1948
    Keywords: Nickel complexes ; Platinum complexes ; S ligands ; C-S cleavage ; Hydride complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nickel and platinum complexes with tridentate ligands, having [S3] or [NS2] donor sets were investigated in order to model active sites of enzymes such as hydrogenases or CO dehydrogenases. Starting from diphenyl sulfide, a preparative synthesis was developed for ‘S3’-H2 [‘S3’-H2 = bis(2-mercaptophenyl) sulfide]. Reactions of ‘S3’-H2 or anionic ‘S3’2- with nickel and platinum precursors resulted in the formation of binuclear [Ni(‘S3’)]2 (1) and trinuclear [Pt(‘S3’)]3 (5). Complex 1 was cleaved by PMe3 or CN- to give the mononuclear complexes [Ni(‘S3’)(PMe3)] (2) and NMe4[Ni(‘S3’)(CN)] (3). Attempts to coordinate hydride to the [Ni(‘S3’)] fragment led to C-S bond cleavage of the ligand and formation of (NMe4)2[{Ni(μ-SC6H5)(S2C6H4)}2] (4). Oxidative addition of Li[‘S3’-H] to [Pt(PPh3)4] afforded the platinum hydride complexes Li[Pt(H)(‘S3’)] and Li[Pt(H)(PPh3)(‘S3’)] which, however, could not be separated from each other and yielded [Pt(‘S3’)(PPh3)] (6) when treated with MeOH. In order to investigate electronic effects of the donor set, the ‘S3’ ligand was modified by alkylation of one thiol group to give ‘RS3’-H derivatives (R = Me, Et, Cy) and by replacing a mercaptophenyl unit by an amine in ‘Et2NS2’-H [‘Et2NS2’-H = N,N-diethyl-2-(2-mercaptothiophenyl)ethylamine]. Reactions of NiII or Ni0 compounds with these ligands in a 1:1 ratio yielded the 1:2 complexes [Ni(‘MeS3’)2] (7), [Ni(‘EtS3’)2] (9) and [Ni(‘CyS3’)2] (10), with ‘RS3’- acting as bidentate ligands only. Complex 7 reversibly reacted with PMe3 to form cis-[Ni(PMe3)2(‘MeS3’)2] (8), exhibiting monodentate ‘MeS3’ ligands. [Ni(‘Et2HNS2’)2]Br2 (11) reacted reversibly with bases to presumably give octahedral [Ni(‘Et2NS2’)2]. Complexes 7, 9 and 10 also did not yield any [Ni(‘RS3’)(H)] hydride complex when treated with hydride sources. Oxidative addition of ‘CyS3’-H to [Pt(PPh3)4] yielded the hydride complexes [Pt(H)(‘CyS3’)] and [Pt(H)(PPh3)(‘CyS3’)] which, however, formed an inseparable mixture and underwent C-S bond cleavage when heated, affording [Pt(o-S2C6H4)(PPh3)2]. The molecular structures of 1, 2, 3, 5, 6, 7, and 11 were determined by X-ray crystallography, revealing butterfly-like shapes for the [MS3L] cores of the complexes.
    Additional Material: 4 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis, Structure, and Properties of Osmium Complexes Containing [Os(′S4′)] and [Os(′S2′)2] Fragments (′S4′2- = 1,2-Bis(2-mercaptophenylthio)ethane(2-), ′S2′2- = 1,2-Benzenedithiolate) (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 819-826 
    Details
    ISSN: 1434-1948
    Keywords: S ligands ; P ligands ; Osmium ; Solvent effects ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In search for osmium complexes with sulfur-dominated coordination spheres that potentially bind and activate or stabilize nitrogenase relevant small molecules, several osmium-sulfur complexes containing 1,2-bis(2-mercaptophenylthio)ethane(2-) (′S4′2-) and benzenedithiolate (′S2′2-) ligands were synthesized. [OsII(PR3)2(′S4′)] [R = Ph (1), Et (2)], [OsIV(PR3)2(′S2′)2] [R = Et (3), Pr(4), Me(5), Ph(6)], [OsIV(PCy3)(′S2′)2] (7), (PHCy3)[OsIII(′S2′)2] (8a), (NMe4)[OsIII(′S2′)2] (8b), and (NBu4)2[OsIV(′S2′)3] (9b) were obtained in reactions starting from commercially available osmium compounds and the sulfur and phosphane ligands. The presence or absence of reducing solvents strongly influenced these reactions. Octahedral (3), (4), and (PHCy3)2[OsIV(′S2′)3] (9a) were characterized by X-ray structure analysis, leading to the conclusion that despite the high oxidation state of the osmium centers, innocent dithiolate ligands are present. The stabilization of the OsIV centers is traced back to S→M π donation. Close inspection of 1 and 2 revealed a large influence of the phosphane ligands on the stability of OsII thioether complexes. While 1 is reasonable stable, 2 readily gives 3 and ethylene via intramolecular ′S4′2- ligand reduction and OsIII→ OsIV oxidation. UV-Vis spectra of 3-5 indicate phosphane dissociation in solution leading to pentacoordinate [Os(PR3)(′S2′)2] complexes. This was confirmed by the synthesis of pentacoordinate [Os(PCy3)(′S2′)2] (7).
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and Exchange Reactions of Sulfur-Rich Nickel and Palladium [M(L)(‘S3’)] Complexes [‘S3’2- = Bis(2-mercaptophenyl)sulfide(2-)] (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 271-279 
    Details
    ISSN: 1434-1948
    Keywords: Nickel complexes ; Palladium complexes ; S ligands ; Exchange reactions ; Azide ; Sulfinylimide ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to obtain suitable precursors for nickel and palladium complexes that model the reactivity of the active sites of hydrogenases and CO dehydrogenases, a series of [M(L)(‘S3’)] complexes has been synthesized [M = NiII, PdII; ‘S3’2- = bis(2-mercaptophenyl)sulfide(2-)]. X-ray structure determinations of [Ni(‘S3’)]3 (1) and [Pd(‘S3’)]3 (2) have revealed that the [M(‘S3’)] fragments trimerize to give six-membered [MS]3 rings, which exhibit chair conformations with alternating MII centers and thiolate bridging atoms. Reactions of the parent complex [Ni(‘S3’)]3 (1) with nucleophiles L, such as thiolates SR- (R = tBu, Cy, Me, Ph), phosphanes PR3 (R = Cy, Ph), chloride, or azide, have been found to yield the corresponding anionic or neutral [Ni(L)(‘S3’)] complexes, which were isolated as (NBu4)[Ni(SR)(‘S3’)] [R = tBu (3), Cy (4), Me (5), Ph (6)], [Ni(PR3)(‘S3’)] [R = Cy (7), Ph (8)], (NBu4)[Ni(Cl)(‘S3’)] (9), and (NBu4)[Ni(N3)(‘S3’)] (10). When treated with Me3SiX, the StBu- ligand in (NBu4)[Ni(StBu)(‘S3’)] (3) was exchanged to give (NBu4)[Ni(X)(‘S3’)] [X = Cl- (9), N3- (10), NCS- (11), NSO- (12)]. The palladium complex [Pd(‘S3’)]3 (2) could also be cleaved with StBu-, but the resulting (NBu4)[Pd(StBu)(‘S3’)] (13) proved inert towards exchange reactions with Me3SiX. All the mononuclear complexes have been characterized by standard spectroscopic techniques and by elemental analysis. The molecular structures of 3, 4, 6, 7, 8, 9, and 13 have been determined by X-ray crystallography. The [MS3L] core geometries of all the complexes are non-planar, exhibiting a considerable tetrahedral distortion.
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