title: Planarity takes over in the C(x)H(x)P(6-x) (x = 0-6) series at x = 4.
abstract: In this work we examine a structural transition from non-planar three-dimensional structures to planar benzene-like structures in the C(x)H(x)P(6-x) (x = 0-6) series. The global minima of P(6), CHP(5), and C(2)H(2)P(4) species are benzvalene-like structures. The benzvalene and benzene-like structures of C(3)H(3)P(3) are close in energy with the former being slightly more stable at our best level of theory. The transition occurs at x = 4 (C(4)H(4)P(2)), where the benzene-like structures become significantly more stable than the benzvalene-like structures. We show that the pseudo Jahn-Teller effect, which is responsible for the deformation of planar P(6), CHP(5), and C(2)H(2)P(4) structures, is completely suppressed at x = 3 (benzene-like structures of C(3)H(3)P(3)). We present NICS(zz) values of all the benzene-like isomers in the series.
authors.affiliation: Department of Chemistry and Biochemistry, Utah State University, Old Main Hill 0300, Logan, UT 84322-0300, USA.
authors.forename: Timur R
authors.initials: TR
authors.lastname: Galeev
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Boldyrev