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Synthesis, Structures, and Reactions of Sulfur‐Rich Nickel and Platinum Complexes with [MS 3 ] and [MNS 2 ] Cores
Author(s) -
Sellmann Dieter,
Häußinger Daniel,
Heinemann Frank W.
Publication year - 1999
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199910)1999:10<1715::aid-ejic1715>3.0.co;2-7
Subject(s) - chemistry , hydride , platinum , nickel , medicinal chemistry , ligand (biochemistry) , sulfide , amine gas treating , ethylamine , oxidative addition , stereochemistry , alkylation , reactivity (psychology) , metal , nickel sulfide , catalysis , organic chemistry , biochemistry , medicine , receptor , alternative medicine , pathology
Nickel and platinum complexes with tridentate ligands, having [S 3 ] or [NS 2 ] 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 ‘S 3 ’‐H 2 [‘S 3 ’‐H 2 = bis(2‐mercaptophenyl) sulfide]. Reactions of ‘S 3 ’‐H 2 or anionic ‘S 3 ’ 2– with nickel and platinum precursors resulted in the formation of binuclear [Ni(‘S 3 ’)] 2 ( 1 ) and trinuclear [Pt(‘S 3 ’)] 3 ( 5 ). Complex 1 was cleaved by PMe 3 or CN − to give the mononuclear complexes [Ni(‘S 3 ’)(PMe 3 )] ( 2 ) and NMe 4 [Ni(‘S 3 ’)(CN)] ( 3 ). Attempts to coordinate hydride to the [Ni(‘S 3 ’)] fragment led to C–S bond cleavage of the ligand and formation of (NMe 4 ) 2 [{Ni(μ‐SC 6 H 5 )(S 2 C 6 H 4 )} 2 ] ( 4 ). Oxidative addition of Li[‘S 3 ’‐H] to [Pt(PPh 3 ) 4 ] afforded the platinum hydride complexes Li[Pt(H)(‘S 3 ’)] and Li[Pt(H)(PPh 3 )(‘S 3 ’)] which, however, could not be separated from each other and yielded [Pt(‘S 3 ’)(PPh 3 )] ( 6 ) when treated with MeOH. In order to investigate electronic effects of the donor set, the ‘S 3 ’ ligand was modified by alkylation of one thiol group to give ‘RS 3 ’‐H derivatives (R = Me, Et, Cy) and by replacing a mercaptophenyl unit by an amine in ‘Et 2 NS 2 ’‐H [‘Et 2 NS 2 ’‐H = N , N ‐diethyl‐2‐(2‐mercaptothiophenyl)ethylamine]. Reactions of Ni II or Ni 0 compounds with these ligands in a 1:1 ratio yielded the 1:2 complexes [Ni(‘MeS 3 ’) 2 ] ( 7 ), [Ni(‘EtS 3 ’) 2 ] ( 9 ) and [Ni(‘CyS 3 ’) 2 ] ( 10 ), with ‘RS 3 ’ − acting as bidentate ligands only. Complex 7 reversibly reacted with PMe 3 to form cis ‐[Ni(PMe 3 ) 2 (‘MeS 3 ’) 2 ] ( 8 ), exhibiting monodentate ‘MeS 3 ’ ligands. [Ni(‘Et 2 HNS 2 ’) 2 ]Br 2 ( 11 ) reacted reversibly with bases to presumably give octahedral [Ni(‘Et 2 NS 2 ’) 2 ]. Complexes 7 , 9 and 10 also did not yield any [Ni(‘RS 3 ’)(H)] hydride complex when treated with hydride sources. Oxidative addition of ‘CyS 3 ’‐H to [Pt(PPh 3 ) 4 ] yielded the hydride complexes [Pt(H)(‘CyS 3 ’)] and [Pt(H)(PPh 3 )(‘CyS 3 ’)] which, however, formed an inseparable mixture and underwent C–S bond cleavage when heated, affording [Pt( o ‐S 2 C 6 H 4 )(PPh 3 ) 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 [MS 3 L] cores of the complexes.