Gold(III)-chloro-diphenylphosphinoammine-arylazoimidazole complexes: Synthesis, spectroscopic and redox study

The complex [AuIII(dppa)Cl2(tht)4](OSO2CF3)4 with ligand addition produce [AuIII(dppa)Cl2(RaaiR′)2](OTf)4 [RaaiR′ = p-RC6 H4NNC3H2NN1-R′, (1-3), abbreviated as N,N′-chelator, where N(imidazole) and N(azo) represent N and N′, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (1), CH2CH3 (2), CH2Ph (3), dppa is diphenylphosphinoamine, OSO2CF3 is triflate anion, tht is tetrahydrothiophen]. IR spectra of the complexes show CN and NN stretching near at 1590 and 1370 cm−1 and near at 1100, 755, 695, 545, 505 cm−1 for dppa. The 1H NMR spectral measurements suggest methylene, -CH2-, in [Au2(dppa)Cl2(RaaiCH2CH3)2]4+, giving a complex AB type multiplet splitting while in [Au2(dppa)Cl2(RaaiCH2Ph)2]4+, AB type quartet splitting. 13C (1H) NMR spectrum suggest the molecular skeleton. Electrochemistry show the ligand reductions at the negative to SCE.