Synthesis and crystal structures of anionic gallium(II) and gallium(III) heterocyclic compounds derived from a gallium(I) N-Heterocyclic carbene analogue

The addition of the Na??H bond of the formamidine, ArN(H)C=NAr (Ar = C6H3Pr2i-2,6), to the gallium(I) center of [K(tmeda)][:Ga(Ar-DAB)] (Ar-DAB= (Ar)NC(H) 2) yields K[(Ar-DAB)GaIII(H) N(Ar)C=NAr 1. The crystal structure of this and two other related anionic compounds, [K(18-crown-6)][(Ar-DAB)GaIII N(H)N=Fl (H)Fl (Fl = fluorendiyl) 2 and [K(OEt2)3][(Ar-DAB)GaII(CH2Ph)GaII(Ar-DAB)] 3, have been determined. The cell parameters of the compounds are 1: P21/c, a = 20.2350(9), b = 14.1760(7), c = 19.6441(10), I? = 111.307(1); 2: P21/c, a = 13.115(3), b = 21.799(4), c = 22.646(5), I? = 90.20(3); 3: P21/n, a = 16.783(3), b = 21.635(4), c = 19.814(4), I? = 92.34(3). The crystal structures of all complexes exhibit distorted tetrahedral gallium centers, and interactions between anion aryl substituents and the potassium cations