The β-dialdiminato ligand [{N(C6H3Pri2-2,6)C(H)}2CPh]−: the conjugate acid and Li, Al, Ga and In derivatives

Abstract

The synthesis of the following crystalline complexes is described: [Li(L)(thf)₂] (2), [Li(L)(tmeda)] (3), [MCl₂(L)] [M = Al (4), Ga (5)], [In(Cl)(L)(µ-Cl)₂Li(OEt₂)₂] (6), [In(Cl)(L){N(H)C₆H₃Prⁱ₂-2,6}] (7), [In(L){N(H)C₆H₃Prⁱ₂-2,6}₂] (8), [{In(Cl)(L)(µ-OH)}₂] (10), [L(Cl)In–In(Cl)(L)] (11) (the thf-solvate 11a, the solvate-free 11b and the hexane-solvate 11c), [{In(Cl)L}₂(µ-S)] (12) and [InCl₂(L)(tmeda)] (13) ([L]⁻ = [{N(C₆H₃Prⁱ₂-2,6)C(H)}₂CPh]⁻). From H(L) (1), via Li(L) in Et₂O, and thf, tmeda, AlCl₃, GaCl₃ or InCl₃ there was obtained 2, 3, 4, 5 or 6, respectively in excellent yield. Compound 6 was the precursor for each of 7–11, 13 and [{InCl₃(tmeda)₂{µ-(OSnMe₂)₂}}] (14) by treatment with one (7) or two (8) equivalents of K[N(H)(C₆H₃Prⁱ₂-2,6)], successively Li[N(SiMe₃)(C₆H₃Prⁱ₂-2,6)] and moist air (10), Na in thf (11a), tmeda (13), or successively tmeda and Me₃SnSnMe₃ (14). Crystals of 11b (with an equivalent of In) and 11c were obtained from InCl or thermolysis of [In(Cl)(L){N(SiMe₃)(C₆H₃Prⁱ₂-2,6)}] (9) {prepared in situ from 6 and Li[N(SiMe₃)(C₆H₃Prⁱ₂-2,6)] in Et₂O}, respectively. Compound 12 was obtained from a thf solution of 11a and sulfur. X-Ray data for crystalline 1–6, 8, 11a, 11b, 11c, 12 and 14 are presented. The M(L) moiety in each (not the L-free 14) has the monoanionic L ligated to the metal in the N,N′-chelating mode. The MN1C1C2C3N2 six-membered M(L) ring is π-delocalised and has the half-chair (2, 3 and 11) or boat (4–8, 10 and 13) conformation.