Methylzinc tetrahydroborate: investigation of the vapour phase by spectroscopic and quantum chemical techniques

Journal article

Methylzinc tetrahydroborate vapour, as shown by its mass and infrared spectra, consists of an equilibrium mixture of monomeric and dimeric species; the proportion of the timer increases as the temperature is raised from 243 to 268 K (at pressures < 10-1 Torr). Consistent with the results of Density Functional Theory (DFT) calculations, the pattern of infrared bands of the matrix-isolated monomer points to a bidentate BH4 group and a tri-coordinate zinc centre. Close agreement between computed and experimentally determined infrared frequencies adds credence to the calculated structural parameters. The nature of the dimer is less certain. The spectroscopic results are consistent with a cyclic structure of the type MeZn(μ2,η2-HB4)2ZnMe; the minimum energy DFT structure features C(2v) symmetry and a puckered eight-membered Zn(μ-H)B(H)2(μ-H)Zn(μ-H)B(H)2(μ-H) ring.

Authors: Aldridge, S; Downs, A; Hofmann, M; Pulham, C; Schleyer, P

• Publication status: Published
• Journal: JOURNAL OF MOLECULAR STRUCTURE
• Volume: 444
• Issue: 1-3
• Pages: 29-46
• Publication date: 1998-03-16
• DOI: 10.1016/S0022-2860(97)00314-1
• ISSN: 0022-2860
• Language: English
• Keywords: matrix isolation; structures; density functional theory; infrared spectroscopy; dimerization; mass spectrometry; methylzinc tetrahydroborate