Some calculated properties of phenylphosphinidene (C6H5P)

Ab initio molecular orbital (MP2/6-311G(d,p) and CASPT2/ANO) and density functionl theory (DFT/IGLO-III) calculations have been applied to determine some basic properties of phenyl phosphinidenee (C6H5P). Geometrics, harmonic vibrational wavenumbers, singlet-triplet energy gaps, heats of formation and hyperfine splitting constants have been calculated. Phenylphosphinidene has a triplet 3A2 ground state lying 22±3 kcal/mol below the closed-shell singlet 1A1 state and some calculated properties are: heat of formation at 0 K ΔH0f,0 = 68 ± 5 kcal/mol, vertical ionization energy IEv = 10.6 ± 0.3 eV, electron affinity EAa = 0.89±03 eV, proton affinity PA = 140±5 kcal/mol and isotropic hyperfine splitting constant a(31P) = 66 ± 3 G. The open-shell singlet 1A2 state is a low-lying state having comparable energy with the 1A1. The properties of C6H5P are similar to those of methylphosphinidene (CH3P). The singlet-triplet gap (1A′–3A2) in CH3P amounts to 26 ± 3 kcal/mol. Relative to the CH3P, the phneyl group has a small effect on the singlet state but seems to destabilize the triplet state and thereby reduce the singlet-triplet gap.