Insights into the Composition and Structural Chemistry of Gallium(I) Triflate

Abstract

“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, 71 Ga NMR spectroscopy 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 [Ag 4 {Ga(OTf) 3 } 4 (μ‐Ga) 6 (OTf) 4 ] 2− .

Insights into the Composition and Structural Chemistry of Gallium(I) Triflate

“…(3). [30] Monoclinic, P2 1 /n, 110 K, R1 = 0.0214, wR 2 (all) = 0.0564. Selected bond lengths [] and angles [8]: Ga1-O1 2.137(1); Ga1-O1-S1 149.71 (8).…”

“…In particular, the gallium center contributes 72 % of the electron 4). [30] Monoclinic, C2/c, 110 K, R1 = 0.0625, wR 2 (all) = 0.1828. Selected bond lengths []: av.…”

“…[30] Monoclinic, P2 (2). [30] Monoclinic, P2 1 /n, 110 K, R1 = 0.0861, wR 2 (all) = 0.2444. The asymmetric unit contains half of the molecular formula, with the other half related to this by a center of inversion.…”

“…[19] While the formal oxidation states of Ga in this anion are different to those in [Ga 3 (OTf) 8 ] 3À their structural parameters are similar, with average GaÀGa bond lengths of 2.378 in 1 and a GaÀGa (1). [30] Monoclinic, P2 1 /c, 110 K, R1 = 0.0784, wR 2 (all) = 0.2303. Some toluene molecules and one [OTf ] À are disordered over two positions.…”

“…Disordered parts are omitted for clarity. Selected bond lengths [] and angles [8]: Ga1-Ga2 2.379(1), Ga2-Ga3 2.377(1), Ga4-C 6 (cent) 2.837-(8) and 2.861(4), Ga6-C 6 (cent) 2.809(12) and 2.831(5); Ga1-Ga2-Ga3 140.31(6), C 6 (cent)-Ga4-C 6 (cent) 121.30 (18), C 6 (cent)-Ga4-C 6 (cent) 126.95 (30). (2).…”