Crystal and Molecular Structure of a Novel Polycyclic Ga, O, N Cage Compound: (GaH)6(GaH2)2(μ3-O)2(μ3-NCH2CH2NMe2)4(μ-NHCH2CH2NMe2)2

Abstract

Crystals of 11H,22H-10,10,21,21-tetramethyl-3,5,14,16-tetra(N,N-dimethyl-2-aminoethyl)-1,12-dioxonia-3,5,7,10,14,16,18,21 -octaazonia-2,4,6,11,13,15,17,22-octagallanata-nonacyclo-[13.7.0.02,7.03,22.04,12.07,11.011,14.013,18.018,22]docosane are triclinic, a = 13.358(1), b = 9.300(1), c = 9.545(1) Å, α = 92.16(2), β = 107.49(1), γ = 89.23(2)°, Z = 1, space group [Formula: see text]. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix least-squares procedures to a final R of 0.038 for 3393 reflections with I ≥ 4σ(I). The bond lengths involving nonhydrogen atoms have been corrected for thermal motion. The molecular structure features a novel Ga, O, N cage structure which includes the first crystallographic examples of four-membered Ga2NO and six-membered Ga3N2O rings. Three of the four crystallographically independent gallium atoms are tetrahedrally four-coordinate with bond lengths: Ga—O, 1.869 and 1.879(2), Ga—N, 1.945–2.001 (3), and Ga—H, 1.40–1.52(4–5) Å. The remaining gallium atom is five-coordinate with distorted trigonal bipyramidal geometry (Ga—O(ax), 1.960(3), Ga—N(ax), 2.779(3), Ga—N(eq), 1.949 and 1.999(3), and Ga—H(eq), 1.49(5)Å). Other bond lengths in the molecule are: N—C, 1.449–1.493(4–10), C—C, 1.486–1.528(6–7), N—H, 0.85(5), and mean C—H, 1.03 Å. The errors quoted above are those arising from the least-squares analysis and do not reflect uncertainties introduced by the thermal analysis.