Neutron Diffraction Study of [K(18-crown-6)] [(PPh3)2ReH6Cr(CO)3], a Bimetallic Donor-Acceptor Complex

Abstract

Keywords: Neutron diffraction / Donor-acceptor complex / Bridging hydride ligand / Rhenium / Chromium A neutron diffraction analysis was carried out at 120 K on a single crystal of [K(18-crown-6)][(PPh 3 ) 2 ReH 6 Cr(CO) 3 ] · THF in order to locate the hydride ligands. Three of the hydrides are bound terminally to the Re atom while the other three bridge the Re-Cr bond; the bridging hydrides are closer to the Re atom. This compound can be thought of as a donor-

[{ReH2(PMePh2)2}2(μ-H)3]-: The First Member of a New Class of Anionic Polyhydride Dimers [Re2H7L4]-

“…The former unsymmetrical dimer was prepared by the reaction of ReH 9 2- with triphos and was shown to contain three bridging hydrides. A few heteronuclear dimers are also known: [(H) 3 (PPh 3 ) 2 Re(μ-H) 3 M(CO) 3 )] - , M = Cr, Mo, W , and [(H) 3 (PPh 3 ) 2 Re(μ-H) 3 U(C 5 Me 5 ) 2 Cl)] - . Here we report the synthesis and characterization of [K(Q)][{Re 2 H 2 (PMePh 2 ) 2 } 2 (μ-H) 3 ] (Q = 18-crown-6 or 1,10-diaza-18-crown-6), the first members of a novel series of anionic dirhenium polyhydride salts of the form [{Re 2 H 2 (L) 2 } 2 (μ-H) 3 ] - .…”