Insights into the composition and structural chemistry of gallium(I) triflate

“GaOTf” is a simple, convenient source of low-valent gallium for synthetic chemistry and catalysis. However, little is currently known about its composition or reactivity. In this work, 71Ga NMR shows the presence of [Ga(arene)n]+ salts on oxidation of Ga metal with AgOTf in arene solvents. However, a more complex picture of speciation is uncovered by X-ray diffraction studies. In all cases, mixed-valence compounds containing Ga-arene and Ga-OTf coordination motifs, in addition to an unusual “naked” [Ga]+ ion, are found. Addition of 18-crown-6 allows for the isolation of a discrete Ga(I) crown complex. Evidence of a potential intermediate in the formation of “GaOTf” has been isolated in the form of the bimetallic silver(I)/gallium(I) cluster anion [Ag4{Ga(OTf)3}4(µ-Ga)6(OTf)4]2-.