title: A Square-Planar Complex of Platinum(0).
abstract: The Pt0complex [Pt(PPh3)(Eind2-BPEP)] with a pyridine-based PNP-pincer-type phosphaalkene ligand (Eind2-BPEP) has a highly planar geometry around Pt with ∑(Pt)=358.6°. This coordination geometry is very uncommon for formal d10complexes, and the Pd and Ni homologues with the same ligands adopt distorted tetrahedral geometries. DFT calculations reveal that both the Pt and Pd complexes are M0species with nearly ten valence electrons on the metals whereas their atomic orbital occupancies are evidently different from one another. The Pt complex has a higher occupancy of the atomic 6s orbital because of strong s-d hybridization due to relativistic effects, thereby adopting a highly planar geometry reflecting the shape and orientation of the partially unoccupied dx2-y2 orbital.
authors.affiliation: International Research Center for Elements Science (IRCELS), Institute for Chemical Research & IRCCS, Kyoto University, Uji, Kyoto, 611-0011, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Takeuchi
authors.affiliation: International Research Center for Elements Science (IRCELS), Institute for Chemical Research & IRCCS, Kyoto University, Uji, Kyoto, 611-0011, Japan.
authors.forename: Hiro-Omi
authors.initials: HO
authors.lastname: Taguchi
authors.affiliation: International Research Center for Elements Science (IRCELS), Institute for Chemical Research & IRCCS, Kyoto University, Uji, Kyoto, 611-0011, Japan.
authors.forename: Ippei
authors.initials: I
authors.lastname: Tanigawa
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka, 577-8502, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Tsujimoto
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka, 577-8502, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Matsuo
authors.affiliation: Institute for Materials Chemistry and Engineering, International Research Center for Molecular Systems & IRCCS, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Institute for Materials Chemistry and Engineering, International Research Center for Molecular Systems & IRCCS, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Yoshizawa
authors.affiliation: International Research Center for Elements Science (IRCELS), Institute for Chemical Research & IRCCS, Kyoto University, Uji, Kyoto, 611-0011, Japan.
authors.forename: Fumiyuki
authors.initials: F
authors.lastname: Ozawa
keywords: phosphaalkene ligands; pincer complexes; platinum; relativistic effects; square-planar complexes