After 20 years, theoretical evidence that 'AuF7' is actually AuF5 center dot F-2

摘要

Quantum-chemical calculations at the DFT (BP86, PBE, TPSS, B3LYP, PBE0), MP2, CCSD, and CCSD(T) levels have been carried out to characterize the putative AuF7 reported in 1986 by Timakov et al. Our calculations indicate clearly that the species claimed to be AuF7 had not been synthesized. Instead, a new gold fluoride complex AuF5 center dot F-2 was prepared. This complex is 205 kJ mol(-1) more stable than the proposed AuF7 species, and the elimination of F-2 is calculated to be endothermic. This is consistent with the reported stability of the product. A reported experimental vibrational frequency at 734 cm(-1) was verified computationally to be the F-F stretching mode of the end-on coordinated F-2 molecule. This result is in line with the recently published trends in the highest attainable oxidation states of the 5d transition metals where Au(V) remains the highest oxidation state of gold.