Redox Potentials of Group 13 Metal-Substituted Dipnictenes: A Comparative Cyclic Voltammetry Study

The electrochemical properties of a series of L­(X)­M-substituted dipnictenes [L­(X)­MPn]2 (1–11; M = Al, Ga; Pn = As, Sb, Bi; X = Cl, OEt, NR2; L = HC­[C­(Me)­NDipp]2; Dipp = 2,6-i-Pr2C6H3) were studied by cyclic voltammetry (CV), showing reversible reduction events except for [L­(Me2N)­AlAs]2 (1) and [L­(Me2N)­AlSb]2 (8) and revealing the influence of the ligand X, the metal M, and the pnictogen Pn on their redox potentials. Dipnictenes [L­(X)­MPn]2 8–11 were prepared by reactions of PnX3 (Pn = Sb, Bi; X = OEt, NR2) with group 13 diyls LM (M = Al, Ga) and characterized by IR, UV/vis, and NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction (sc-XRD). The dibismuthene [L­(EtO)­GaBi]2 (11) was further found to decompose in solution at ambient temperature with partial formation of the tetrabismuthane ([{L­(EtO)­Ga}2-μ,η1:1-Bi4] (15).