Dalton communications. The synthesis of the first examples of water-soluble seven-co-ordinate complexes of tungsten(II)

Abstract

Reaction of the seven-co-ordinate complex [WI₂(CO)₃(NCMe)₂] with two equivalents of 4-HO₂CC₅H₄N in methanol at room temperature gave the bis(pyridine-4-carboxylic acid) complex [Wl₂(CO)₃(4-HO₂CC₅H₄N)₂]1 in good yield, which, upon treatment with two equivalents of NaOH in ethanol, afforded the completely water-soluble complex [Wl₂(CO)₃(4-NaO₂CC₅H₄N)₂]2 in good yield; reaction of the latter with an equimolar amount of 3-NaO₃SC₅H₄N yielded [Wl₂(CO)₃(4-NaO₂CC₅H₄N)(3-NaO₃SC₅H₄N)], which represents the first room-temperature ligand-substitution reaction in water of a metal carbonyl complex.