Lewis-Base Adducts of Main Group 1 Metal Compounds. IV. Synthesis and Structure of the XLiL₃ System (X = Cl, Br, I, L = 4-t-Butylpyridine, and X = I, L = Quinoline)

Abstract

Complexes [XLiL₃], X = Cl , Br, I; L = 4-t-butylpyridine, (1)-(3) have been synthesized by recrystallization of the anhydrous lithium halide from the parent base, and characterized structurally by single-crystal X-ray structure determination. (1) and (2) are isomorphous (monoclinic, P2₁), a ≈ 11.8, b ≈ 12.1, c ≈ 11.8 Ǻ, β 120°, Z 2 (R 0.051, 0.040 for N_o 1491, 1499 'observed' reflections); (3) is orthorhombic, Pbca, a 22.119(10), b 21.108(10), c 12.845(10) Ǻ, Z 8, R 0.067 for N_o 967. (1)- (3) are all pseudo- trigonal and contain four-coordinate XLiN₃ arrays [Li-X, 2.33(1); 2.53(1); 2.76(4) Ǻ; Li-N, 2.03(1)-2.11(1); 2.04(1)-2.09(2); 2.03(4)-2.07(4)Ǻ]. Similar data are also recorded for X = I, L = quinoline (4)[monoclinic, P2₁/c, a 15.684(6), b 7.693(4), c 26.758(12) Ǻ,β 107.71(3)°, Z 4; R 0.072, N_o 3096; Li-I, 2.78(2); Li-N, 2.08(2)- 2.13(2)Ǻ]. While a close parallel may be drawn between the similarity of the chemistry of lithium(I) and copper(I) in respect of (1)-(3), (4) is unusual being the first XML₃ derivative for a quinoline -type ligand; it is a monoquinoline solvate.