PNNL

Abstract

BO- is isoelectronic with CN-.1 However, in comparison to CN-, which is an important ligand in inorganic and biomolecules, the chemistry of BO- is relatively unknown. The electron affinity (EA) of BO (2.51 eV)2,3 is much smaller than that of CN (3.86 eV),4 which may explain the fact that CN- is a stable anion in solution, but BO- is not. However, the electronic structure and bond strength of BO- are similar to those of CN-, suggesting that it may be a robust chemical unit and can retain its structural integrity in chemical compounds. In a recent study, we indeed found that BO behaves like a monovalent structural unit in its bonding to Au in AunBO- (n ) 1-3) clusters.5 Theoretical calculations also suggested that carbon boronyls (CBO)n (n ) 3-7) are stable species on the potential-energy surfaces.6 Here we report a photoelectron spectroscopy (PES) and theoretical study on two boron oxide clusters, B3O2 - and B4O3 -, which are shown to possess a D¥h (3ªg) linear and D3h (2A2¢¢) triangular structure, respectively, and can be viewed as two and three boronyl groups bonded to a single B atom.