Platinum complexes mixed-ligand with

A series of mixed-ligand thiosalicylato complexes of the type PtL(PPh3)Y2] (Y2 = thiosalicylate L = pyridine, 4-methylpyridine, picolinic acid hydrazide, imidazole) have been prepared by the reaction of [PtCl2(COD)] with PPh3, thiosalicylic acid, and A-donor ligand in MeOH solution.375 The X-ray structure of the pyridine derivative (162) was determined, the first example of where a platinum atom is coordinated to a N, O, P, and S donor atom set. 

A comparative study of the tetrammine complex [Pt(NH3)4]+ has shown that for platinum, adenine is a better cr donor than ammonia but it has weak n capacity <93JCC45>. Mixed-ligand complexes of m-dichloroethionine-Pd(II) with purines and purine nucleosides have also been prepared. In the complexes of purines and their corresponding nucleosides, the ligand binding site is N-7 whereas in the case of pyrimidines and their nucleosides it is N-3 <90ICA129>. 

Complexes of Pt can be tetrahedral, planar three-coordinate, or hnear two-coordinate. Soft ligands and n-acceptor ligands are required to stabilize this low oxidation state. Acetylenes ([Pt(/ -PhC=CPh)2]), olefines (([Pt() -PhCH=CH2)3)]), and especially phosphines are the most common ligands found in zerovalent complexes of platinum. Compounds with mixed ligands, including p-block elements donor ligands, are also known. 

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