Structural transformations in the carborane series: CnB6-nH6 (n=0-6) upon substitution of boron by carbon

Abstract

In this paper we examined a structural transition from three-dimensional to two-dimensional in the CnB6−nH6 (n = 0–6) series. The searches for all the isomers of clusters were performed using the stochastic search algorithm at the B3LYP/6-31G level of theory. Subsequent geometry optimizations at the hybrid density functional B3LYP/6-311++G∗∗ level of theory along with single-point CCSD(T) calculations were carried out to estimate relative energies. We found that 3D-2D transition occurs at n = 5 (C5BH6). Moreover, the stability of clusters is discussed on the basis of the binding energy per atom, second-order energy difference, adiabatic ionization potential, HOMO–LUMO energy gap and polarizability. Based on the simultaneous criteria of high binding energy, high band gap, high adiabatic ionization potential and low polarizability, it is found that C2B4H6 cluster has a higher stability.