Computational study of the (CH3Zn)2B3H7 and CH3ZnBH4 dimers

Density functional theory (DFT) has been used to study the structure and binding of two zinc tetraborate dimers. Both dimers ([(CH3Zn)2B3H7]2 and [CH3ZnBH4]2) display an interesting five-coordinate geometry around zinc including four Zn–H–B bridges and one terminal methyl group. The binding energy of the [(CH3Zn)2B3H7]2 dimer is predicted to be 6.5 kcal/mol at the DFT (B3LYP) level and 16.5 kcal/mol at the MP2 level. In comparison, the binding energy of [CH3ZnBH4]2 is predicted to be 10.2 and 14.2 kcal/mol at the DFT and MP2 levels, respectively. A comparison is made with the X-ray structure of [(CH3Zn)2B3H7]2.