Synthesis, Structure, and Reactivity of a Superbulky low‐Valent β‐diketiminate Ga(I) Complex

A low-valent Ga$^I$ complex with the superbulky β-diketiminate ligand $^{DIPeP}$BDI (HC[C(Me)N−DIPeP]$_2$, DIPeP=2,6-C(H)Et$_2$-phenyl)) was obtained by reduction of ($^{DIPeP}$BDI)Ga$^I$$_2$ (1) with KC$_8$ in toluene. Considering that (BDI)GaI and analogue (BDI)AlI complexes are prone to decomposition and can generally only be obtained in low yields (20–40 %), the quantitative formation of ($^{DIPeP}$BDI)Ga$^I$ (2) is remarkable and no doubt related to its excellent thermal stability even in refluxing toluene. Although the low-valent metal center in 2 is sterically protected by the superbulky $^{DIPeP}$BDI ligand, it is readily oxidized by N$_2$O to give intermediate ($^{DIPeP}$BDI)Ga=O which readily decomposed by abstracting a proton from the backbone Me-substituent. Reaction with trimethylsilyl azide gave an intermediate imido complex ($^{DIPeP}$BDI)Ga=N(SiMe$_3$)$_2$ which reacted with a second equivalent of Me$_3$SiN$_3$ to a mixture of an azide/amido complex ($^{DIPeP}$BDI)GaN$_3$[N(SiMe$_3$)$_2$] (4) and a tetrazagallole complex ($^{DIPeP}$BDI)Ga[N$_4$(SiMe$_3$)$_2$] (5) in a 1 : 2 ratio. Whereas the azide/amido complex 4 could be structurally characterised, the tetraazagallole complex 5 was identified by NMR spectroscopy. ... mehrDFT calculations on (DIPePBDI)Ga$^I$ (2) and its reaction products complement this study.