6 Group 13–15 Needle-Shaped Oligomers and Nanorods: Structures. . .
215
In earlier study [118], cyclotrigallazane [H 2 GaNH 2 ] 3 was found to decompose
with evolution of H 2 and ammonia and formation of the polymeric product,
insoluble in Et 2 O. Pyrolysis of this product at 300–600 ◦ C yields Ga-N. Several
possible structures were proposed for [HGaNH] n imino gallanes; authors [115]
concluded that the best candidate is the planar hexagonal network. Considered
alternatives included a molecular cluster that is large enough to be insoluble, or
more complex (perhaps microporous) solid-state structure [115].
In 2005, synthesis and characterization of series of [(RGaNH) 3 ] n oligomers have
been performed by Kormos et al. using reactions of [RGa(NMe 2 )] 2 with ammonia at
high pressures at 150 ◦ C (R=Me,Et,Bu,Hx) [119]. X-ray powder diffraction results
are in agreement with needle-shaped arrangement of Ga 3 N 3 rings (Fig. 6.7).
Fig. 6.7 Packing of H 3 [(HxGaNH) 3 ] 12 H 3 along c axis (top view on the rod, which is aligned to c
axis). (Reprinted with permission from [119]. Copyright 2005 American Chemical Society)