Abstract
A series of Group 13 complexes MLX 2 (M = Al or Ga, L = SC 6 H 4 -2-P t Bu 2 or OC 6 H 4 -2-P t Bu 2 , X = Me or C 6 F 5 ) have been synthesized and characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction. Reactions of Me 3 Al or Me 3 Ga with an equivalent of either 2- t Bu 2 P(C 6 H 4 )OH (1) or 2- t Bu 2 P(C 6 H 4 )SH (5) resulted in the formation of four new (2,3,6, and 7), 4-coordinate dimethyl chelate (S,P or O,P) complexes via methane elimination. The dimethyl gallium complexes (3 and 7) underwent a further reaction with excess B(C 6 F 5 ) 3 , and through ligand exchange (methyl/pentafluorophenyl), resulted in the disubstituted bis(pentafluorophenyl) analogs (4 and 8). Cyclic voltammetry (CV) experiments for all compounds in the presence of and the absence of (1–8) CO 2 were performed. For compounds showing cathodic reduction waves under CO 2 (2,3,4, and 6), bulk electrolysis experiments were performed. Electrochemical studies indicate that, for several compounds, a transient CO 2 adduct is formed which undergoes a one-electron, irreversible (or partially irreversible) reduction to form an unstable radical anion.