Increasing the solubility of strong reducing agents containing Mo24+ units and alkyl-substituted guanidinate ligands†‡
Abstract
Six very soluble paddlewheel compounds containing Mo2n+ units, n = 4, 5, 6, and two alkyl-substituted bicyclic guanidinate ligands have been synthesized. The quadruply bonded complexes with n = 4, Mo2(TMhpp)4 and Mo2(TEhpp)4, (TMhpp = the anion of 3,3,9,9-tetramethyl-1,5,7-triazabicyclo[4.4.0]dec-4-ene and TEhpp = the anion of 3,3,9,9-tetraethyl-1,5,7-triazabicyclo[4.4.0]dec-4-ene) are easily oxidized. The electrode potentials in THF are −1.08 and −1.17 V vs. Ag/AgCl, respectively, for the Mo25+/4+ couple. These potentials are in accord with the low ionization potentials for the quadruply bonded compounds. Because of the high solubility of the Mo24+ compounds in most common organic solvents they are attractive candidates for use as strong reducing agents in homogeneous systems.