Pyridine-2-thionate as a versatile ligand in Pd(ii) and Pt(ii) chemistry: the presence of three different co-ordination modes in [Pd2(μ2-S,N-C5H4SN)(μ2-κ2S-C5H4SN)(μ2-dppm)(S-C5H4SN)2]

Abstract

Reactions of [MCl₂(L–L)], M = Pt, Pd; L–L = bis(diphenylphosphino)methane (dppm) or bis(diphenylphosphino)ethane (dppe), with NaC₅H₄SN in a 1 : 2 molar ratio lead to mononuclear species [M(S-C₅H₄SN)₂(P–P)], M = Pt; L–L = dppm (1) or dppe (2) and M = Pd; L–L = dppe (3), as well as to the dinuclear [Pd₂(μ₂-S,N-C₅H₄SN)(μ₂-κ²S-C₅H₄SN)(μ₂-dppm)(S-C₅H₄SN)₂] (4). In contrast, reaction of [MCl₂(dppm)] with NaC₅H₄SN in a 1 : 1 molar ratio leads to [Pd₂(μ₂-S,N-C₅H₄SN)₃(μ₂-dppm)]Cl (5) and trans-[Pt(S-C₅H₄SN)₂(PPh₂Me)₂] (6) respectively. The latter is formed in low yield by cleavage of the dppm ligand. The dinuclear derivatives 4 and 5 present an A-frame and lantern structure, respectively. The former showing three different co-ordination modes in the same molecule with a short Pd–Pd distance of 2.9583 (9) Å and the latter with three bridging S,N thionate ligands showing a shorter Pd–Pd distance of 2.7291 (13) Å. Both distances could be imposed by the bridging ligands or point to some sort of metal–metal interaction.