Synthesis and Photophysical Properties of Cyclometalated Platinum(II) 1,2-Benzenedithiolate Complexes and Heterometallic Derivatives Obtained from the Addition of [Au(PCy3)]+ Units

The cyclometalated compounds [Pt(C^N)(HC^N)Cl] [HC^N = 2-phenylpyridine (Hppy; 1a), 1-(4-tert-butylphenyl)isoquinoline (Htbpiq; 1b)] react with 1,2-benzenedithiol, t-BuOK, and Bu4NCl in a 1:1:2:1 molar ratio in CH2Cl2/MeOH to give the complexes Bu4N[Pt(C^N)(bdt)] [bdt = 1,2-benzenedithiolate; C^N = ppy (Bu4N2a), tbpiq (Bu4N2b)]. In the absence of Bu4NCl, the same reactions afford solutions of K2a and K2b, which react with [AuCl(PCy3)] to give the neutral heterometallic derivatives [Pt(C^N)(bdt){Au(PCy3)}] [C^N = ppy (3a), tbpiq (3b)]. The cationic derivatives [Pt(C^N)(bdt){Au(PCy3)}2]ClO4 [C^N = ppy (4a), tbpiq (4b)] are obtained by reacting 3a and 3b with acetone solutions of [Au(OClO3)(PCy3)]. The crystal structures of 3b and 4b reveal the formation of short Pt···Au metallophilic contacts in the range 2.929–3.149 A. Complexes 3b, 4a, and 4b undergo dynamic processes in solution that involve the migration of the [Au(PCy3)]+ units between the S atoms of the dithiolate. Complexes Bu4N2a and 2b display a mo...