Organoplatinum(II) complexes with phosphite ligands

The phosphite complexes cis-PtMe₂L(SMe₂)] in which L = P(OⁱPr)₃, 1a, or L = P(OPh)₃, 1b, were synthesized by the reaction of cis,cis-Me₂Pt(μ-SMe₂)₂PtMe₂] with 2 equiv. of L. If 4 equiv. of L was used the bis-phosphite complexes cis-PtMe₂L₂] in which L = P(OⁱPr)₃, 2a, or L = P(OPh)₃, 2b, were obtained. The reaction of cis-Pt(p-MeC₆H₄)₂(SMe₂)₂] with 2 equiv. of L gave the aryl bis-phosphite complexes cis-Pt(p-MeC₆H₄)₂L₂] in which L = P(OⁱPr)₃, 2a′, or L = P(OPh)₃, 2b′. Use of 1 equiv. of L in the latter reaction gave the bis-phosphite complex along with the starting complex in a 1:1 ratio.The complexes failed to react with MeI. The reaction of cis,cis-Me₂Pt(μ-SMe₂)₂PtMe₂] with 2 equiv. of the phosphine PPh₃ gave cis-PtMe₂(PPh₃)₂] and cis-PtMe₂(PPh₃)(SMe₂)] along with unreacted starting material. Reaction of cis-PtMe₂L(SMe₂)], 1a and 1b with the bidentate phosphine ligand bis(diphenylphosphino)methane, dppm = Ph₂PCH₂PPh₂, gave PtMe₂(dppm)], 8, along with cis-PtMe₂L₂], 2. The reaction of cis-PtMe₂L(SMe₂)] with 1/2 equiv. of the bidentate N-donor ligand NN = 4,4′-bipyridine yielded the binuclear complexes PtMe₂L(μ-NN)PtMe₂L] in which L = P(OⁱPr)₃, 3a, or L = P(OPh)₃, 3b.The complexes were fully characterized using multinuclear NMR (¹H, ¹³C, ³¹P, and ¹⁹⁵Pt) spectroscopy.