Macrocyclic Chromium(III) Catecholate Complexes.

The synthesis and structural, electrochemical, spectroscopic, and magnetic characterizations of Cr(HMC) catecholate and semiquinonate complexes are reported herein, where HMC is 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane. [Cr(HMC)(Cat)] complexes (Cat = catecholate, []; tetrachlorocatecholate, []; and 3,5-di--butylcatecholate, []) were prepared from the reaction between appropriate catechol and [Cr(HMC)Cl]Cl reduced by zinc. Chemical oxidation of [] by FcPF resulted in -[Cr(HMC)(SQ)] ([], SQ = 3,5-di--butylsemiquinonate).