Synthesis, structures and properties of platinum(II) complexes of oligoacetylenic sulfides

A series of novel platinum(II) acetylide complexes incorporating sulfur-lin ked oligoalkynes have been prepared. The CuI-catalysed dehydrohalogenation reactions of the mono-protected dialkyne ligand HC=CSC=C(TIPS) (TIPS = (Pr3 Si)-Si-i) with trans-[Pt(PBu3)(2)Cl-2], cis-[Pt(dppe)Cl-2] or cis-[Pt(Me(2) bipy)Cl-2] (Me(2)bipy = 4,4'-dimethyl-2,2'-bipyridine), in the presence of a base, readily produced trans-[Pt(PBu3)(2){C=CSC=C(TIPS)}(2)] 1, cis-[Pt(d ppe){C=CSC=C(TIPS)}(2)] 3 and cis-[Pt(Me(2)bipy){C=CSC=C(TIPS)}(2)] 7, resp ectively, in good yields. Similar synthetic procedures using a diacetylenic sulfide species HC=CSC=CC=CSC=C(TIPS) afforded trans-[Pt(PBu3)(2){C=CSC=CC =CSC=C(TIPS)}(2)] 2 and cis-[Pt(dppe){C=CSC=CC=CSC=C(TIPS)}(2)] 4, both of which contain eight triple-bond units within the molecular entity. Two new metallo-end-capped derivatives trans-[Ph(Et3P)(2)Pt-C=CSC=C-Pt(PEt3)(2)Ph] 5 and trans-[Ph(Et3P)(2)Pt-C=CSC=CC=CSC=C-Pt(PEt3)(2)Ph] 6 were also synthe sized in moderate yields by reactions of two equivalents of trans-[PtPh(Cl) (PEt3)(2)] and the diterminal acetylenic sulfides HC=CSC=CH and HC=CSC=CC=C SC=CH in a CuI/(Me3Si)(2)NH system. All of the compounds 1-7 have been char acterized by IR, NMR (H-1, C-13 and P-31) and UV/VIS spectroscopies, lumine scence measurements and mass spectrometry. The solid-state molecular struct ures of 5 and 7 have been established by X-ray crystallography.