Cycloplatinated Complexes of Thiosemicarbazones. Synthesis and Crystal Structure of [Ph₂PC₆H₄CHNNC(S)NHCH₃PtCl]

The synthesis and characterization of the platinum heterocyclic carboxaldehyde thiosemicarbazone complexes [NC₅H₄CRNNC(S)NHR'PtCl] (R=H, R'=CH₃(1); R=CH₃, R'=CH₃(2); R=CH₃, R=H(3)) and diphenylphosph- inophenyl carboxaldehyde thiosemicarbazone complexes [Ph₂PC₆H₄CHNNC(S)NHRPtCl] (R=CH₃(5); R=ⁱC₃H₇ (6); R=Ph(7)) are described. Compounds 1-3 were prepared by reaction of Pt(SEt₂)₂Cl₂ with 2-acetylpyridine-4-alkylthiosemicarbazone in the presence of NEt₃. Compounds 5-7 were prepared using Pt(SEt₂)₂Cl₂ in toluene with diphenylphosphinophenyl carboxaldehyde alkylthiosemicarbazone. The compounds have been characterized by microanalysis, NMR (¹H, ¹³C, ³¹P) spectroscopy, and single-crystal X-ray diffraction. X-ray single crystal diffraction analysis reveals that compound 5 is a mononuclear platinum compound with P,N,S-coordination mode.