LEWIS-BASE ADDUCTS OF MAIN GROUP-1 METAL-COMPOUNDS .15. ADDUCTS OF LITHIUM(I) PERCHLORATE WITH ORTHO-METHYL-SUBSTITUTED MONODENTATE PYRIDINE BASES OF INCREASING BULK

Whereas recrystallization of CuIClO4 from the progressively bulky pyridine bases (L) pyridine (py), 2-methylpyridine (2-mpy) and 2,6-dimethylpyridine (2,6-dmpy) yields adducts of progressively diminishing base stoichiometry, n = 4, 3, 2 (in [CuLn](ClO4)), recrystallization of LiClO4 from the same bases yields adducts [Li(py)4](ClO4) and polymeric, perchlorate-bridged Li(2-mpy/2,6-dmpy)2(ClO4). The former is tetragonal, I 4BAR, a 12.479(5), c 7.009(8) angstrom, Z 2, and isomorphous with the copper analogue; R was 0 - 057 for 324 'observed' reflections, and Li-N 2.066(7) angstrom [cf. Cu-N, 2.046(4) angstrom]. Li(2-mpy)2(ClO4) is monoclinic, P2(1)/c, a 16.004(4), b 10.020(3), c 8.831(5) angstrom, beta-99.56(3)-degrees, Z 4, R 0.047 for 1402 'observed' reflections, while Li(2,6-dmpy)2(ClO4) is monoclinic, C2/c, a 22.089(9), b 10.067(5), c 15.715(6) angstrom, beta-110.54(3)-degrees, Z 8, R 0.041 for 1991 'observed' reflections. The latter compounds have Li2N2O2 coordination environments about the metal of an irregular nature, presumably in consequence of ligand hindrance.