Reaction of Me3Ga and Me3Al with the tertiary-tetraaza analog of adamantane, hexamethylenetetramine (N4-Ada). Syntheses and molecular structures of [(Me3M)n · N4-Ada] (n = 1–4, M Ga or Al)
作者:Jameica B. Hill、Sheila J. Eng、William T. Pennington、Gregory H. Robinson
DOI:10.1016/0022-328x(93)80180-j
日期:1993.2
Reaction of Me3Al or Me3Ga with hexamethylenetetramine, N4-Ada (Ada = adamantane), in toluene affords the crystalline addition products [(Me3M)n . N4-Ada] (n = 4, M = Ga (1); n = 3, M = Ga (11); n = 3, M = Al (111); n = 2, M = Ga (IV); n = 2, M = Al (V); n = 1, M = Ga (VI). Compound I crystallizes in the triclinic space group P1BAR (no. 2) with unit cell parameters a = 10.365(3), b = 11.814(6), c = 11.991(6) angstrom, alpha = 94.16(4), beta = 92.56(3), gamma = 92.44(3)-degrees, V = 1461(1) angstrom3, and D(calc) = 1.36 g cm-3 for Z = 2. Least-squares refinement based on 2600 observed reflections converged at R = 0.075, R(w) = 0.089. Compound III crystallizes in the monoclinic space group P2(1)/c (no. 14) with unit cell parameters a = 7.416(2), b = 16.687(6), c = 19.143(6) angstrom, beta = 91.71(2)-degrees, V = 2368(1) angstrom3, and D(calc.) = 1.00 g cm-3 for Z = 4. Least-squares refinement based on 2235 observed reflections converged at R = 0.085, R(w) = 0.102. The mean Ga-N bond distance in I is 2.29 (3) angstrom, while the corresponding Al-N distance is 2.11 (1) angstrom. The Ga-N distance of 2.318 (9) angstrom in I is the longest such distance reported. A molecular mechanics study was used to show that the sequential addition of Me3M (M = Al or Ga) units to N4-Ada significantly affects the relative Lewis basicities of the nitrogen atoms of the amine.