The route to highly stable MeB_xN_yC_z molecular wheels. I. The features of preliminary results

摘要

By means of ab initio quantum chemical methods we have determined the energies and electronic structures of molecular wheels TiB_n, TiB_nN_(10-n), TiC_nN_(10-n) and TiC_nB_(10-n) (for n = 0-10). The ground state energies and the corresponding spin states of each atom, cluster and molecular wheel were calculated first in the framework of Hartree-Fock self-consistent-field (HF-SCF) using minimal and more accurate basis sets STO-3G and 6-31G. Computations at higher level and accuracy are processing in a follow-up study. The most stable wheel system is TiC_nB_(10-n) (for n = 5-10). Thereof particularly highly stable is the TiC_5B_5 molecular wheel followed by the TiC_6B_4. At the HF-SCF/6-31G level, however, we have calculated the wheel system MeC_5B_5 considering for Me, the first row of transition metal atoms Me = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn. The molecular wheel MeC_5B_5 favours Sc atom at the centre, but also Ti and Fe are the next favoured atoms.