New bromo-, triflato-, and hydridotricarbonylrhenium(I) complexes with diphosphinite ligands: Structural, spectral and protonation studies of various hydrides
作者:Sandra Bolaño、Jorge Bravo、Jesús Castro、Soledad García-Fontán、Ma Carmen Marín、Pilar Rodríguez-Seoane
DOI:10.1016/j.jorganchem.2005.08.014
日期:2005.11
Bromotricarbonylrhenium(I) complexes [ReBr(CO)(3)L] [L = Ph2PO(CH)(3)OPPh2 (L), (Pr2PO)-Pr-i(CH2)(2)(OPPr2)-Pr-i (L-2), Cy2PO-(CH2)(2)OPCy2 (L)] were prepared by reaction of [ReBr(CO)51 with L. X-ray crystallography showed them all to be mononuclear, with the CO ligands fac. Subsequent reaction with AgOTf gave fac-[Re(OTf(CO)(3)L], as shown by IR and NMR spectra. By contrast, reaction of [ReH(CO)(5)] with L1-3 gave hydrido complexes, the nuclearity and stereochemistry of which depended on the identity of L, as was confirmed by X-ray crystallography of mer-[ReH(CO)(3)L-1], fac-[ReH(CO)(3)L-2] and [(ReH(CO)4}2(p-L 3)]. Protonation of the hydrido compounds at 183 K with HBF4 center dot OMe2 gave the corresponding non-classical cationic dihydrogen complexes (T-1(min) similar to 15 ms at 400 MHz), which released H-2 at temperatures above critical temperatures (243-263 K) that depended oil the co-ligands. (c) 2005 Elsevier B.V. All rights reserved.
Oxorhenium(V) complexes with bis-phosphinite chelating coligands. The crystal structure of [ReOCl2(OMe)L1], [ReOCl3L2], [ReOCl2(OEt)L2] and [ReOCl2{Ph2PO(CH2)2O}{PPh2(OEt)}] [L1=Cy2PO(CH2)2OPCy2, L2=Ph2PO(CH2)2OPPh2]
The new ligand 1,2-bis(dicyclohexylphosphinite)ethane (L-1) was prepared by reaction of ethylenglycol with dicyclohexylphosphine in the presence of triethylamine. By treating this ligand with the arsine complex [ReOCl3(AsPh3)(2)] and trituring the formed oil with methanol, the complex [ReOCl2(OMe)L-1] (1) was isolated and its crystal structure was studied by X-ray diffractometry. The coordination sphere around the Re atom is a pseudo-octahedron. The crystal structure of the previously reported complex [ReOCl3L2] (2) (L-2 = 1,2-bis[diphenylphosphinite]ethane) was solved by X-ray diffractometry. When Complex 2 was refluxed in EtOH, the oxo-alkoxide complex [ReOCl2(EtO)L-2] (3) was formed by a metathesis reaction. X-ray diffraction studies of Complex 3 show a pseudo-octahedral geometry around the Re atom with the oxo and ethoxy groups mutually trans. Finally, reaction of 2 with the monodentate phosphinite PPh2(OEt) ligand yielded the paramagnetic Re(111) compound [ReCl3L2 PPh2(OEt)}] (previously reported) and the new unexpected Re(V) by-product [ReOCl2(Ph2POCH2CH2O)PPh2(OEt)}] (4). On the contrary, compounds I and 3 did not react with PPh2(OEt) under the same conditions. (C) 2003 Elsevier Science Ltd. All rights reserved.
Synthesis of 1,2-bis[(diorgano)phosphino]ethanes via Michaelis–Arbuzov type rearrangements
作者:Lawrence C Baldwin、Mark J Fink
DOI:10.1016/s0022-328x(01)01431-0
日期:2002.3
the bisphosphinites R2POCH2CH2OPR2 (R=Ph, iPr and Cy) at 190–260 °C for 24 h gave the bisphosphine oxides, R2P(O)CH2CH2(O)PR2 in 9% (Ph), 90% (iPr) and 93% (Cy) yields. A DSC study of the thermal rearrangement of Cy2POCH2CH2OPCy2 to Cy2P(O)CH2CH2(O)PCy2 yielded an enthalpy of isomerization of −40.4±0.6 kcal mol−1. Reduction of the bisphosphine oxides, R2P(O)CH2CH2(O)PR2 (R=Ph, iPr and Cy) with trichlorosilane