Transition metal complexes with sulfur ligands, 139 - Synthesis and exchange reactions of sulfur-rich nickel and palladium [M(L)('S-3')] complexes ['S-3'(2-) = bis(2-mercaptophenyl)sulfide(2-)]

In order to obtain suitable precursors for nickel and palladium complexes t hat model the reactivity of the active sites of hydrogenases and CO dehydro genases, a series of [M(L)('S-3')] complexes has been synthesized [M = Ni-I I, Pd-II; 'S-3'(2-) = bis(2-mercaptophenyl)sulfide(2-)]. X-ray structure de terminations of [Ni('S-3')](3) (1) and [Pd('S-3')](3) (2) have revealed tha i the [M('S-3')] fragments trimerize to give six-membered [MS](3) rings, wh ich exhibit chair conformations with alternating M-II centers and thiolate bridging atoms. Reactions of the parent complex [Ni('S-3')](3) (1) with nuc leophiles L, such as thiolates SR- (R = tBu, Cy-, Me, Ph), phosphanes PR, ( R = Cy, Ph), chloride, or azide, have been found to yield the corresponding anionic or neutral [Ni(L)('S-3')] complexes, which were isolated as (NBu4) [Ni(SR) ('S-3')] [R = tBu (3), Cy (4), Me (5), Ph (6)], [Ni(PR3)('S-3')] [R = Cy (7), Ph (8)], (NBu4)[Ni(Cl) ('S-3')] (9), and (NBu4) [Ni(N-3)('S-3')] (10). When treated with Me3SiX, the StBu(-) ligand in (NBu4)[Ni(StBu) ('S- 3')] (3) was exchanged to give (NBu4)[Ni(X)('S-3')] [X=Cl- (9), N-3(-) (10) , NCS- (11), NSO- (12)]. The palladium complex [Pd('S-3')](3) (2) could als o be cleaved with StBu-, but the resulting (NBu4) [Pd(StBu)('S-3')] (13) pr oved inert towards exchange reactions with Me3SiX. All the mononuclear comp lexes have been characterized by standard spectroscopic techniques and by e lemental analysis. The molecular structures of 3, 4, 6, 7, 8, 9, and 13 hav e been determined by X-ray crystallography. The [MS3L] core geometries of a ll the complexes are non-planar, exhibiting a considerable tetrahedral dist ortion.