title: A combined theoretical and experimental study of simple terminal group 6 nitride and phosphide N[triple bond]MX3 and P[triple bond]MX3 molecules.
abstract: Organometallic complexes containing terminal metal nitrides and phosphides are important synthetic reagents. Laser-ablated group 6 metal atoms react with NF 3, PF 3, and PCl 3 to form the simple lowest energy N[triple bond]MF 3, and P[triple bond]MX 3 products following insertion and halogen transfer, with the exception of P[triple bond]CrF3, which is a higher energy species and is not observed. The E[triple bond]MX3 pnictide metal trihalide molecules are identified from both argon and neon matrix infrared spectra and frequencies calculated by density functional theory and multiconfigurational second-order perturbation theory (CASSCF/CASPT2). These simple terminal nitrides involve strong triple bonds, which range from 2.80 to 2.77 to 2.59 natural bond order for M = W, Mo, and Cr, respectively, as computed by CASSCF/CASPT2, and the M[triple bond]N stretching frequencies also follow this order. The terminal phosphides are weaker with bond orders 2.74, 2.67, and 2.18, respectively, as the more diffuse 3p orbitals are less effective for bonding to the more compact metal valence d orbitals.
authors.affiliation: Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Wang
authors.forename: Lester
authors.initials: L
authors.lastname: Andrews
authors.forename: Roland
authors.initials: R
authors.lastname: Lindh
authors.forename: Valera
authors.initials: V
authors.lastname: Veryazov
authors.forename: Björn O
authors.initials: BO
authors.lastname: Roos