Abstract
The B-trichloroborazine (TCB) and its derivatives with alkyl amine borazine are the effective precursor to the preparation of hexagonal BN (h-BN). On account of the specific structures of TCB and its derivatives will make some influences on the preparation reactions, in this work, by means of density functional theory, we perform a theoretical estimation of the reaction characterization of TCB and its derivatives. The results show that the order of the Wiberg bond index is Cl>H>NHCH3>N(CH3)2 (1.081>1.002>0.9874>0.9432). Furthermore, the gap energy of frontier orbit of TCB, Cl2[N(CH3)2]B3N3H3, Cl[N(CH3)2]2B3N3H3 and [N(CH3)2]3B3N3H3 is 784.2 KJ/mol, 666.5 KJ/mol, 695.8 KJ/mol and 674.2 KJ/mol.
It is shown that the reactivity of TCB and its substituents are in the following order: TCB < Cl[N(CH3)2]2B3N3H3 < [N(CH3)2]3B3N3H3 < Cl2[N(CH3)2]B3N3H3. All the results demonstrate that the one alkyl amine derivative has the better reaction activity than TCB and the other two derivatives. Then we consider the influences on the reaction induced by the N(CH3)2 and NHCH3 in the TCB derivatives. It is verified that the gap energy of the substitution reaction on NHCH3 derivatives is greater than that on the N(CH3)2 derivatives, demonstrating that the derivatives of N(CH3)2 has a higher reaction activity than that of NHCH3. This work should be of some significance for estimating the reaction activity and product in the preparation of h-BN.
