Matrix infrared spectroscopy of F2BMF and FBWF2 (M = Cr, Mo and W) complexes and quantum chemistry calculations

Abstract

Laser-ablated group 6 transition metal atoms react with BF₃ to yield typical transition metal inserted complexes F₂B-MF (M = Cr, Mo, and W) and terminal borylene complex FBWF₂. These products are investigated by using infrared spectroscopy, isotopic substitution and theoretical frequency calculations. The inserted complexes F₂B–MF (M = Cr, Mo, and W) were identified by antisymmetric and symmetric stretching modes of F–B–F. The FBWF₂ molecule has a ¹¹B–F (¹⁰B–F) stretching frequency at 1453.2 (1505.0) cm⁻¹ and the triple bond between boron and tungsten is confirmed by EDA-NOCV calculations, CASSCF calculation and NBO analysis. Furthermore, the bonding for tungsten complexes is compared with that of molybdenum and chromium complexes, which reveals interesting differences in their chemistries.