St. Barry et Ds. Richeson, PREPARATION AND CHARACTERIZATION OF MIXED ALKYL AMIDO COMPLEXES OF GALLIUM, Journal of organometallic chemistry, 510(1-2), 1996, pp. 103-108
A series of primary amido gallium alkyl complexes that includes a base
free dimer, [(t)Bu(2)Ga(mu-N(H)(t)Bu)](2) (1), Lewis base stabilized
monomeric complexes, (n)Bu(2)Ga(N(H)(t)Bu)(THF) (2) and (n)Bu(2)Ga[NH(
2,6-Me(2)C(6)H(3))]py (3) and an anionic complex, (n)Bu(2)Ga[NH(2,6-Me
(2)C(6)H(3))](2)[Li(Et(2)O)] (4) is reported. Complex 1 crystallizes i
n the triclinic space group P-1 (a = 10.265(5) Angstrom, b = 15.752(6)
Angstrom, c = 8.932(4) Angstrom, alpha = 90.32(3)degrees, beta = 105.
61(3)degrees, gamma = 88.24(4)degrees) with two molecules, each residi
ng on an inversion center, in the asymmetric unit. Structural analysis
revealed a planar Ga2N2 core with both the bridging N and the Ga cent
ers in distorted tetrahedral environments (Ga-C distances 2.052(3)-2.0
65(3) Angstrom and Ga-N distances 2.060(3)-2.069(3) Angstrom). The use
of excess amido ligand allowed the isolation and crystallization of 4
. Complex 4 crystallized in the monoclinic space group P2(1)/n (a = 8.
666(2) Angstrom, b = 22.305(3) Angstrom, c = 15.570(3) Angstrom, beta
= 103.47(2)) with Z = 4. The pseudotetrahedral gallium center has a co
ordination sphere composed of two amido ligands (Ga-N1 = 2.011(8) Angs
trom, Ga-N2 = 2.006(7) Angstrom), and two (n)Bu ligands (Ga-C17 = 2.00
2(9) Angstrom, Ga-C21 = 1.985(12) Angstrom). A bridging interaction of
the lithium cation with the lone pair of electrons on each of amido n
itrogen atoms generates a molecular core which is made up of a planar
Ga-N1-Li-N2 distorted square (N1-Ga1-N2 94.4 degrees, Ga1-N2-Li1 86.2
degrees, N1-Li1-N2 92.2 degrees, Ga1-N1-Li1 87.1 degrees).