Formation and Calculations of the Simple Terminal Triplet Pnictinidene Molecules N÷MF3, P÷MF3, and As÷MF3 (M = Ti, Zr, Hf)

Abstract

Laser-ablated Ti, Zr, and Hf atoms react with NF(3), PF(3), or AsF(3) to produce triplet state terminal pnictinidene N/MF(3), P/MF(3), or As/MF(3) molecules, which are trapped in an argon matrix. Products are identified from infrared spectra and comparison to theoretically predicted vibrations. Density functional theory calculations converge to C(3v) symmetry structures for these lowest energy products. The two unpaired electrons in nitrogen 2p, phosphorus 3p, or arsenic 4p orbitals are shared in different small amounts with empty metal nd orbitals leading to very weak degenerate pialpha molecular orbitals based on bonding orbital analysis and spin density calculations. This weak pi bonding interaction with early transition metal group 4 nd orbitals is optimum for Zr with phosphorus 3p orbitals.