Bis(dimethylamido) Complexes of Alkyl- and Phenylgallium. Useful Precursors to the RGa²⁺ Synthon

Abstract

Alkyl- and phenylbis(dimethylamido)gallium, [RGa(NMe(2))(2)](2) [R = Me (1), Et (2), (n)Bu (3), (n)Hx (4), and Ph (5)], were synthesized by reactions of LiNMe(2) with (RGaCl(2))(2). The crystal structure of compound 1 was a disordered mixture of anti and syn isomers, with the ratio of anti/syn being 64:36, which was consistent with the ratio (57:43) found in the (1)H NMR spectrum. The Ga(2)N(2) cores of the anti and syn structures were nonplanar. (1)H NMR spectra indicated the presence of both anti and syn isomers for all of the other substituents. (1)H NMR and mass spectra indicated that a species with the general formula of R(3)Ga(2)(NMe(2))(3) was formed when these compounds were heated at high temperatures.

Synthesis and X-ray crystallographic structures of [HGa(NMe2)2]2 and [PhGa(NHNMe2)2]2, and room-temperature conversions of [HGa(NMe2)2]2 to (HGaNH)n and (HGaNMe)n

“…The total integrated areas for each of the two groups were equal. Referenced to [RGa(NMe 2 ) 2 ] 2 (R ¼ Me and Et) [7], the resonances at 2.31-2.47 ppm were assigned to the bridging NMe 2 ligands, and at 2.79-2.96 ppm, to the terminal NMe 2 ligands. The singlets at 2.33 and 2.93 ppm, accounting for 60% of the total NMe 2 resonances, were assigned to the trans structure (Scheme 1(a)) found in the solid state.…”

“…The internal angle on Ga was 87.03(6)°. Within the group of bis(dimethylamido) gallium compounds, [ClGa-(NMe 2 ) 2 ] 2 [14] has a trans solid-state structure while both trans and cis structures for [MeGa(NMe 2 ) 2 ] 2 [7] were found in the solid state. For 2, the internal angle on Ga (85.39(8)°) was very close to that found in (Et 2 GaNHNPh 2 ) 2 (85.8(3)°) [15].…”

“…Dimethylhydrazine, benzene-d 6 and toluene-d 8 were distilled over CaH 2 under nitrogen. The quinuclidine dichlorogallane adduct, HGaCl 2 (quinuclidine) [17] and bis(dimethylamido) phenylgallium, [PhGa(NMe 2 ) 2 ] 2 [7] were prepared as previously reported. LiNMe 2 was prepared as a white powder from the reaction of HNMe 2 with 1 equivalent of n-butyllithium in hexanes.…”

“…In essence, [RGa(NMe 2 ) 2 ] 2 serves as a useful synthon for the ''RGa 2þ '' moiety [7]. In this paper we report the extension of this reaction to form a new bis(dimethylhydrazido) complex of phenylgallium.…”

4 Aluminium, gallium, indium and thallium

“…R 3 Ga 2 (NMe 2 ) 3 was formed when these compounds were heated. 81 The chiral organogallium alkoxide [(thf )MeGa(S-BINOLate)] 2 {S-BINOL = (S-2,2Ј-dihydroxy-1,1Ј-binaphthyl)} was prepared, the dimer structure had a Ga 2 O 2 ring. 82 , was also prepared.…”