Synthesis, spectroscopic characterization, crystal structure determination and DFT calculations of [Au(Me2phen)Br2][AuBr2]

New mixed valence gold(III/I) salt containing two complexes [Au(Me2phen)Br2][AuBr2] (1) was prepared from the reaction of AuBr3 and 5,6-dimethyl-1,10-phenanthroline (Me2phen) in a mixture of methanol and acetonitrile. Suitable crystals of 1 for X-ray diffraction measurement were obtained by slow evaporation of the resulted red solution at room temperature. This complex was characterized by spectral methods (IR, UV–Vis and 1H NMR), elemental analysis and single-crystal X-ray diffraction. The X-ray structural analysis indicated that the asymmetric unit of 1 contains one [Au(Me2phen)Br2]+ cation and two half anions of [AuBr2]ˉ. Furthermore, the packing diagram of this complex, 3-D structure stabilized by intermolecular Au…Br and Au…π interactions and intermolecular C–H···Br hydrogen bonds. The experimental investigations on complex have been accompanied computationally by the density functional theory (DFT) and time-dependent DFT calculations. The nature of the Au–N bonds was investigated using quantum theory of atoms in molecules. Moreover, natural bond orbital analysis carried out to obtain hyper-conjugative interactions and electron delocalization on the complex.