Metal-heterocyclic thione interactions. 12. Heterocyclic 2-thiolates of platinum(II) and palladium(II): the crystal structures of first examples of cis-[M(eta(1)-S-pyridine-2-thiolato)(2)( L-L)] {M = Pt, Pd, L-L=1,2-bis(diphenylphosphino) ethane; M = Pt, L-L=1,2-bis( diphenylphosphino) ethene} complexes

A series of platinum(II) complexes of stoichiometry cis-[Pt(eta'-S-C5H4NS), (L-L)] were obtained from the reactions of platinum tetrachloride with pyri dine-2-thione (C5H5NS) in the presence of Et3N base in an ethanol-benzene m ixture followed by the addition of his (tertiary phosphines), viz.{Ph2P-X-P Ph2}, or phosphine charcogenides {Ph2P-CH2-P(E)Ph-2} {X(L-L)= (CH2)(2)(dppe ) (1), CH=CH(dppen) (2), (CH2)(3)(dppp) (3), (CH2)(4)(dppb) (4), E=S, dppmP S (5), E=Se, dppmPSe (6)}. Palladium(TI) complexes, viz. [Pd(eta'-S-C5H4NS) (2)(L-L)] {L-L=dppm (X=CH2) (7), dppe (8), dppp (9), dppmPS (10), dppmPSe ( 11)}, were prepared by reacting [ PdCl2 ( diphosphines )] suspended in etha nol with C5H5NS in the presence of aqueous NaOH. All these compounds have b een characterised with the help of analytical data [LR, far-IR, NMR (H-1, C -13, P-31) spectroscopy] and X-ray crystallography (for compounds 1, 2 and 8). The geometry about each metal centre is distorted square planar with tr ans bond angles of: compound 1, P-Pt-S, 170.31(11), 173.18(10)degrees; comp ound 2, P-PtS, 168.97(5), 171.43(5)degrees; compound 8, P-Pd-S, 170.78(8), 171.83(8)degrees The bite angles P(1)-M-P(2) and angles trans to bite angle s, S(1)-M-S(2), are, respectively: compound 1, 85.68(11), 82.69(11)degrees; compound 2, 86.65(5), 84.01(6)degrees; compound 8, 85.19(8), 83.90(7)degre es. The dppe complexes (1 and 8) are isomorphous, monoclinic with space gro up C2/c, whereas the dppen complex is triclinic. These compounds represent the first examples of an interesting series of cis-platinum(II) and -pallad ium(II) derivatives of pyridine-2-thione containing chelating diphosphines and pendant pyridyl groups. (C) 2000 Elsevier Science Ltd All rights reserv ed.