Quantifying effects of second-sphere cationic groups on redox properties of dimolybdenum quadruple bonds.

A series of four dimolybdenum paddlewheel complexes supported by anionic N , N -dimethylglycinate (DMG) or zwitterionic N , N , N -trimethylglycine (TMG) ligands was synthesised to examine the effects of charged groups in the second coordination sphere on redox properties of MoMo bonds. An average shift in reduction potential of +35 mV per cationically charged group was measured, which is approximately half of what would be expected for an analogous mononuclear complex.