Cui-Ping Xiao

Substitution reactions of H2GeFBeF with RH (R = F, OH, NH2): A theoretical study

A combined density functional and ab initio quantum chemical study of the substitution reactions of the germylenoid H2GeFBeF with RH (R = F, OH, NH2) compounds was carried out. The geometries of all the stationary points of the reactions were optimized using the DFT B3LYP method and then the QCISD method was used to calculate the single-point energies. The theoretical calculations indicated that along the potential energy surface, there were one transition state (TS) and one intermediate (IM) which connected the reactants and the products. The three substitution reactions of H2GeFBeF with RH are compared with the addition reactions of H2Ge with RH. And based on the calculated results we concluded that the substitution reactions of H2GeFBeF + RH involve two steps. One is dissociation onto H2Ge + BeF2, and the other is the addition reaction of H2Ge with RH.

A new reaction mode of germanium-silicon bond formation: insertion reactions of H2GeLiF with SiH3X (X = F, Cl, Br)

A combined density functional and ab initio quantum chemical study of the insertion reactions of the germylenoid H2GeLiF with SiH3X (X = F, Cl, Br) was carried out. The geometries of all the stationary points of the reactions were optimized using the DFT B3LYP method and then the QCISD method was used to calculate the single-point energies. The theoretical calculations indicated that along the potential energy surface, there were one precursor complex (Q), one transition state (TS), and one intermediate (IM) which connected the reactants and the products. The calculated barrier heights relative to the respective precursors are 102.26 (X = F), 95.28 (X = Cl), and 84.42 (X = Br) kJ mol-1 for the three different insertion reactions, respectively, indicating the insertion reactions should occur easily according to the following order: SiH3-Br > SiH3-Cl > SiH3-F under the same situation. The solvent effects on the insertion reactions were also calculated and it was found that the larger the dielectric constant, the easier the insertion reactions. The elucidations of the mechanism of these insertion reactions provided a new reaction model of germanium-silicon bond formation.

Theoretical prediction on the insertion reactions of the germylenoid H2GeLiF with GeH3X (X = F, Cl, Br)

The insertion reactions of the germylenoid H2GeLiF with the halogenated germane GeH3X (X = F, Cl, Br) were studied using the DFT B3LYP and QCISD methods. The geometries of the stationary points on the potential energy surfaces of the reactions were optimized at the B3LYP/6-311+G(d, p) level of theory. Then the single-point energies were calculated at the QCISD/6-311++G(d, p) level. The calculated results indicated that along the potential energy surface, there are one precursor complex (Q), one three-memberedring transition state (TS), and one intermediate (IM), which connected the reactants and the products. The illustrations of the mechanism of the insertion reactions provided a new reaction mode of germanium-germanium bond formation.