The pH dependent phase transfer of an organometallic complex: synthesis, characterization, and crystal structure of a W(0) tetracarbonyl with an acidic pyridine-imine ligand

Reaction of the asymmetrical pyridine-imine ligand L (where L = benzoic acid, 3-[(2-pyridinylmethylene)amino]) with W(CO)(3)(EtCN)(3) and CO (g) affords a W(0) tetracarbonyl in which the Schiff-base ligand coordinates in a bidentate fashion. The complex was characterized by IR, NMR, and UV-visible spectroscopy and elemental analysis. The solid-state structure of W(CO)(4)(L), which crystallized in the orthorhombic space group Pbca with unit cell parameters a = 22.497(4) Angstrom, b = 14.112(6) Angstrom, and c = 13.675(3) Angstrom was established by X-ray crystallography. Deprotonation of the -CO2H group on the ligand with base results in the formation of a water-soluble organometallic complex which can be partitioned between organic and aqueous phases in a biphasic system by pH adjustment. (C) 2003 Elsevier B.V. All rights reserved.