Gold-dppm-Arylazoimidazole Complexes: Synthesis, Spectra, and Redox Study

Abstract

[Ag(tht)(OTf)]-assisted reaction produces [AuIII(dppm)(tht)2](OSO2CF3)2, reacts with RaaiR′ in dichloromethane medium followed by ligand addition, and leads to [AuIII(dppm)(RaaiR′)](OTf)2(RaaiR′=p–R–C6H4–N=N–C3H2–NN–1–R′, (1–3), abbreviated as N,N′-chelator, where N(imidazole) and N(azo) represent N and N′, resp.; R = H (a), Me (b), Cl (c) and R′= Me (1), CH2CH3(2), CH2Ph (3), dppm is diphenylphosphinomethane, OSO2CF3 is the triflate anion, and tht is tetrahydrothiophen). Ir spectra of the complexes show –C=N– and –N=N– stretching near at 1590 and 1370 cm−1 and near at 1100, 755, 695, 545, and 505 cm−1 due to the presence of dppm. The H1 NMR spectral measurements suggest that methylene, –CH2–, in RaaiEt gives a complex AB type multiplet while in RaaiCH2Ph it shows AB type quartets. Electrochemistry assigns ligand reduction.