title: Pincer ligands with an all-phosphorus donor set: subtle differences between rhodium and palladium.
abstract: The synthesis of a new, all-phosphorus pincer PP(NEt2)P ligand L3(NEt2), which is derived from 2-indolylphosphine and features a central N(2)P(NEt(2)) core, is described. This 'PPP' species shows coordination toward Rh as a neutral trisphosphine ligand. Tridentate diphenylphosphine-derived PP(H)P ligands L1(H) and L2(H), featuring a secondary phosphine core, show 'ambivalent' coordination, acting as persistent neutral triphosphine ligands with Rh, and as easily-formed monoanionic phosphido(bisphosphine) pincer ligands toward Pd. These subtle differences, which might be more general for group 9 and 10 metal complexes with this ligand set, are explained by comparative DFT calculations (BP86; def2-TZVP level of theory) for the Rh and Pd species involved, including those with the structurally related PN(H)P ligands. The optimized structure for complex PdCl(L2) indicates minimal overlap of available Pd d-orbitals with the lone pair of the central, deprotonated phosphorus atom (formally a phosphido fragment), suggesting that it behaves predominantly like a bulky phosphine instead of a phosphido fragment.
authors: Supramolecular & Homogeneous Catalysis, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors: Richard C
authors: RC
authors: Bauer
authors: Yann
authors: Y
authors: Gloaguen
authors: Martin
authors: M
authors: Lutz
authors: Joost N H
authors: JN
authors: Reek
authors: Bas
authors: B
authors: de Bruin
authors: Jarl Ivar
authors: JI
authors: van der Vlugt