Salicylaldimine Dizinc Complexes: Activation of Water Molecules and Fixation of CO2 in the Coordination Sphere of Zinc

Abstract

Bi- and tetranuclear zinc complexes of the tridentate N,N,O ligand [{[2-(2-pyridyl)ethyl]imino}methyl]phenol (HL) and their enzyme-like reactions are described. The coordinated water molecules in a dizinc complex of this ligand can be deprotonated reversibly similar to those in the resting states of zinc enzymes. The resulting tetranuclear complex bearing bridging hydroxide ions allows the reversible uptake of CO2. Whereas the coordination of hydrogen carbonate has not been observed, a tetranuclear carbonate complex with a unique structure was isolated. Its carbonate ion is coordinated to all four zinc atoms. The X-ray structures of the reported complexes are discussed. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)