The starting complexes [PtCl(C^N)(dmso)], in which C^N is either ppy = 2-phenylpyridinate, 1a, or bhq = 7,8-benzo[h]quinolinate, 2a, were prepared by a known method using the reaction of [PtCl₂(dmso)₂] with ppyH or bhqH, respectively, in toluene under reflux conditions. The reaction of [PtCl(C^N)(dmso)], 1a or 2a, with 1 equiv. of a number of biphosphine ligands, P^P, gave the cationic monomeric complexes [Pt(ppy)(P^P)]Cl, for which P^P is either 1,2-bis(diphenylphosphino)ethane (dppe), 3a, 1,3-bis(diphenylphosphino)propane (dppp), 3c, or bis(diphenylphosphino)methane (dppm), 3d; the bhq analogous complex [Pt(bhq)(dppe)]Cl, 4a, was prepared similarly. However, the complex [Pt(ppy)(dfppe)]Cl, 3b, in which dfppe is 1,2-bis(dipentafluorophenylphosphino)ethane, was prepared by the reaction of 1a with excess amount of dfppe. When each of the starting complexes [PtCl(C^N)(dmso)], 1a or 2a, were reacted with 0.5 equiv. of any of the P^P ligands, the dimeric complexes [Pt₂Cl₂(ppy)₂(μ-P^P)], 5a–5d, or [Pt₂Cl₂(bhq)₂(μ-P^P)], 6a–6b, were formed. The complexes were fully characterized using multinuclear (¹H and ³¹P) NMR spectroscopy and elemental analysis. The structures of typical complexes 3a, 3c, 5b, and 5d were also confirmed by X-ray crystallography. The effect of ligands on the luminescent properties of the complexes was investigated and DFT calculations were performed to confirm the assignments.

Reaction of each of the known starting complexes [PtR(C^N)(SMe₂)], 1, in which R = Me or p-MeC₆H₄ and C^N is either ppy (deprotonated 2-phenylpyridine) or bhq (deprotonated benzo[h]quinoline), with one equivalent of CF₃CO₂H, gave the complexes [Pt(C^N)(CF₃CO₂)(SMe₂)], 3 (C^N = ppy, 3a; bhq, 3b). The bis-chelate complexes [Pt(C^N)(P^P)](CF₃CO₂), 4, were obtained by reaction of complexes 3 with one equivalent of either of the P^P bisphosphine reagents, dppf = 1,1′-bis(diphenylphosphino)ferrocene or dppe = bis(diphenylphosphino)ethane. Complexes 4 were alternatively made by reaction of the complexes [PtMe(κ¹C-C^N)(P^P)], 2, with one equivalent of CF₃CO₂H. When the complex 3b was reacted with 0.5 equivalents of dppe, 0.5 equivalents of the related bis-chelate product, 4d, formed along with 0.5 equivalents of the unreacted starting complex 3b. In contrast, when the complex 3b was reacted with 0.5 equivalents of dppf, then the dimeric complex [Pt₂(bhq)₂(CF₃CO₂)₂(μ-dppf)], 5, formed in pure form. In all the above-mentioned acid reactions, the M–R bond rather than the M–C bond of the cycloplatinated complex is cleaved. When the PPh₃ analogues of complexes 1, i.e. the complexes [PtR(C^N)(PPh₃)], 6, in which C^N is ppy or tpy = deprotonated 2-p-tolylpyridine, were reacted with one equivalent of CF₃CO₂H, the course of the reaction reversed and the M–C bonds of the cycloplatinated complexes are cleaved rather than the M–R bonds. The latter reaction gave [PtR(κ¹N-HC^N)(PPh₃)(CF₃CO₂)], as an equilibrium mixture of two isomers 7 and 8. Crystal structures of the typical complexes show a variety of extensive intermolecular hydrogen bonding involving C–H bonds from the different ligands and electronegative atoms (O or F) from the CF₃CO₂ moiety. On the basis of data obtained from kinetic studies (using ¹H NMR spectroscopy), a dissociative mechanism is proposed for the case of the 7c/8c isomerization process, involving dissociation of the κ¹N-Htpy neutral ligand, rather than the alternative route of PPh₃ or CF₃CO₂ ligand dissociation.

Reaction of [PtAr₂(NN)] (Ar = Ph, p-MeC₆H₄, m-MeC₆H₄ or p-MeOC₆H₄; NN = 2,2′-bipyridyl or 1,10-phenanthroline) with R₂O₂, in which R = H or C(O)Ph, gives the platinum(IV) complexes cis,trans-[PtAr₂(OH)₂(NN)] or [PtAr₂(OCOPh)₂(NN)] (as a 5 ∶ 1 mixture of cis,trans and cis,cis isomers), respectively. The kinetics of these oxidative addition reactions in acetone was followed by visible spectrophotometry between 10 and 40 °C. The reactions followed simple second-order kinetics, rate = k₂[PtAr₂(NN)][peroxide], and the rates were insensitive to change of solvent. Activation parameters have been determined and large negative values for ΔS^≠ were obtained. A mechanism is suggested which involves a concerted three-center transition state, followed by homolytic cleavage of the O–O bond and formation of the final products.

The luminescent properties of cycloplatinated complexes containing aryl and SMe ₂ ligands, [Pt( p -MeC ₆ H ₄ )(ĈN)(SMe ₂ )], (ĈN = benzo[ h ]quinolate (bzq), 1 , or 2-phenylpyridinate (ppy), 2 ), were investigated in solution and solid state.