Tuning a Metal's Oxidation State:The Potential of Clathrochelate Systems

摘要

"Oxidation state" is one of most fundamental concepts in chemistry.The stabilization of previously unknown or unusual oxidation states of metal ions allows us to obtain results that are important both for theoretical inorganic chemistry and for the design of new molecular electronic devices,electrochro-mic materials,and electron-storage systems.Complexes with a metal ion encapsulated in a three-dimensional macropolycyclic ligand cavity have undoubted promise in stabilizing unusual oxidation states of such caged ions.This is due to the fact that an encapsulated and coordinatively saturated metal ion is completely isolated from environmental factors (in particular,effects of solvation and additional coordination that exclude occurrence of redox processes by bridge mechanisms).The size of a three-dimensional ligand cavity may be controlled by changing the nature of the capping and chelating fragments of the macropolycyclic framework,and donor atoms (groups) that are optimal for stabilization of a desired electronic configuration of this ion may be chosen.