Gold behaves as hydrogen: prediction on the existence of a new class of boron-containing radicals, AuBX (X = F,Cl,Br).

In this Communication we have reported the prediction of a new class of compounds, AuBX (with X = F,Cl,Br), using the results obtained from ab initio quantum-chemical calculations. We have compared their electronic structures, bonding, and stability with that of the recently discovered HBX radicals and demonstrated an excellent one-to-one quantitative correspondence between the structures, nature of bonding, and stability of AuBX radicals with the corresponding HBX radicals, which is of considerable significance. Comparison has also been made with the radicals containing other coinage metal atoms, viz., CuBX and AgBX. Structurally they are found to be quite similar to the HBX radicals. However, the stability in terms of some of the bond dissociation energy values differs considerably from the corresponding values in HBX or AuBX species. This feature is attributed to the unusually high relativistic effects in gold. The present results suggest that AuBX radicals are stable enough to be prepared experimentally in analogy with the experimentally observed HBX radicals. The gold-hydrogen analogy demonstrated here quantitatively would motivate further research to predict gold analogs of novel hydride species and vice versa.