title: Stability of phosphinidenes--are they synthetically accessible?
abstract: The relative stability of different singlet phosphinidenes (R-P) has been investigated by using isodesmic reactions. The energies of these reactions with several R groups were calculated with DFT and ab initio methods at different levels of theory. The best stabilising effect on the phosphinidene centre is exhibited by the R'2C=N-group, resulting in a singlet ground state. The analysis of the electron density in the parent H2C=N-P, indicates a considerable double bond character of the PN bond. Further tuning of the C=N pi-bond polarity is possible by variation of the R' substituents. Using trimethylsilyl substituents or incorporating the carbon atom in a pi-withdrawing pentafulvene ring the stabilization and the computed singlet triplet separation increases. The thermodynamics and the kinetics of dimerisation reactions of the most stabilised R'2C=N-P indicates that these compounds are likely synthetic targets.
authors.affiliation: Department of Inorganic Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, H-1521, Budapest, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Benko
authors.forename: Rainer
authors.initials: R
authors.lastname: Streubel
authors.forename: László
authors.initials: L
authors.lastname: Nyulászi