Oxorhenium(V) complexes with bis-phosphinite chelating coligands. The crystal structure of [ReOCl2(OMe)L-1], [ReOCl3L2], [ReOCl2(OEt)L-2] and [ReOCl2{Ph2PO(CH2)(2)O} {PPh2(OEt)}] [L-1=Cy2PO(CH2)(2)OPCy2, L-2=Ph2PO(CH2)(2)OPPh2]

摘要

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. [References: 36]