Oxo-rhenium(V) complexes containing bridging phosphito ligands. The synthesis, characterisation and X-ray crystal structures of [ReOCl{μ-OP(OR)2}{OCMe2CMe2OP(OCMe2CMe2O)}]2 (R=Me or CMe2)
摘要:
The oxo-rhenium(V) complexes [ReOCl2(P similar to O)L] (P similar to O = (OCMe2CMe2O)PoCMe2CMe2O-), L = py (1), PPh3 (2) or OPPh3 (3)) react with P(OMe)(3) or spirophosphorane HP(OCMe2CMe2O)(2) (HP similar to O) affording the related mu -phosphito(1-) bridged dimeric compounds [ReOCl{mu -OP(OR)(2)}(P similar to O)](2) (R = Me (4) or -CMe2 (5)). The mu -phosphito ligands result from Arbuzov-like dealkylation reactions. Complexes 4 and 5 were characterised by NMR, IR, LTV-VIS spectroscopic methods. In solution, both the light brown complexes 4 and 5 remain dimeric and comprise two equivalent six-coordinated monomeric subunits stereochemically rigid at ambient temperature. The complexes appeared to be rather inert in attempted substitution reactions. In the crystal state, in spite of the molecular C-i symmetry of 4, complex 5 reveals a distorted pseudocentrosymmetric C-1 geometry. The multiply bonded terminal oxo ligands. (Re=O 1.681(5) Angstrom (4), 1.684(5) and 1.691(5) Angstrom (5)) are in cis arrangements to two phosphito bridges. Two different phosphito bridged cores Re{mu -OP(OR)(2)}(2)Re (R = Me (4), -CMe2 (5)) adopt the chair conformation. (C) 2001 Elsevier Science Ltd. All rights reserved.