The chiral Pt(II) phosphido complex Pt(dppe)(Me)[P(Mes)(Men)] (dppe = Ph2PCH2CH2PPh2, Mes = 2,4,6-Me3C6H2, Men = (−)menthyl, 1) was prepared by proton transfer from racemic mesityl(−)menthylphosphine to the methoxide ligand of Pt(dppe)(Me)(OMe). Treatment of Pt(dcpe)[CH(Me)(CN)](Br) with alkali metal phosphides gives Pt(dcpe)[CH(Me)(CN)](PRR‘) (dcpe = Cy2PCH2CH2PCy2, Cy = cyclo-C6H11, R = H, R‘ = Mes* = 2,4,6-(t-Bu)3C6H2, 13; R = Me, R‘ = Ph, 14). The related series of complexes Pt(diphos*)(Me)(PRR‘) (diphos* = S,S-Chiraphos, R = Ph, R‘ = Is = 2,4,6-(i-Pr)3C6H2), 5; R = Me, R‘ = Mes*, 6; diphos* = R-Tol-Binap, R = Me, R‘ = Mes*, 7) containing chiral diphosphine ligands has been prepared by deprotonation of the cations [Pt(diphos*)(Me)(PHRR‘)][BF4] 2, 3, and 4, respectively. The cations, synthesized from Pt(diphos*)(Me)(Cl), AgBF4, and the appropriate secondary phosphine, were isolated as a mixture of diastereomers (2 and 3) or a single isomer (4). Phosphido complexes 1 and 5−7 show only one set of 31P NMR...