Gallium hydride and monovalent indium compounds that feature tris(pyrazolyl)hydroborate ligands

Abstract

The tris(pyrazolyl)hydroborate compounds [tris(3,5-dimethyl-1H-pyrazol-1-yl-κN(2))hydroborato]indium(I), [In(C15H22BN6)], abbreviated as [Tp(Me2)]In, and [tris(3-tert-butyl-5-methyl-1H-pyrazol-1-yl-κN(2))hydroborato]indium(I), [In(C24H40BN6)], abbreviated as [Tp(Bu(t),Me)]In, represent well defined examples of three-coordinate monovalent indium. In both compounds, the geometry at indium is pyramidal and natural bond orbital (NBO) calculations indicate that the indium lone pair occupies an orbital that is primarily 5s in character. The trivalent gallium hydride compound hydrido[tris(3-tert-butyl-5-methyl-1H-pyrazol-1-yl-κN(2))hydroborato]gallium(III) tetrachloridogallium(III), [Ga(C24H40BN6)H][GaCl4], abbreviated as {[Tp(Bu(t),Me)]GaH}[GaCl4], is obtained via reaction of [Tp(Bu(t),Me)]Tl with [HGaCl2]2, and the Ga-H bond length of 1.49 (6) Å compares favorably with the mean value of 1.50 Å for structurally characterized gallium hydride compounds that are listed in the Cambridge Structural Database.

Molecular Main Group Metal Hydrides

“…Structure of the cationic component of [(3,5- Me,tBu Tp)­GaH]­[GaCl 4 ] ( 637 ) in the solid state as determined by single crystal X-ray crystallography. Reproduced with permission from ref . Copyright 2013 International Union of Crystallography.…”

“…Thus, the reaction of tridentate tri(pyrazolyl)borate donor [3,5-Me,tBu Tp] − with dichlorogallane leads to the formation of the [(3,5-Me,tBu Tp)-GaH] + cation, partnered with a tetrachlorogallate counterion (637; Figure 51). 829 Ehm, Lentz, and coworkers have reported an interesting use of Me 3 N•GaH 3 (or better Li[GaH 4 ] or [ t Bu 2 Ga(μ-H) 2 ] (638) in the presence of an O-or N-donor ligand such as diglyme or NEt 3 ) to bring about the hydrodefluorination of vinylic and aromatic C−F bonds. DFT calculations imply that the likely mechanism involves a hydrometallation/elimination sequence.…”

Bis- and Tris(2-oxobenzimidazolyl)hydroborato Complexes of Sodium and Thallium: New Classes of Bidentate and Tridentate Oxygen Donor Ligands

“…The data presented in Tables and illustrate that the O–Tl–O angles are acute (74.9–84.1°), such that the thallium centers of [To RBenz ]Tl are highly pyramidal. For an approximate C 3 coordination environment, a simple gauge of the pyramidality ( P ) of a MX 3 moiety is provided by the magnitude of the deviation of the sum of the three X–M–X interactions from 360°, i.e., P = 360° – ∑(X–M–X), and comparison with the data for [Tm RBenz ]­Tl indicates that the thallium in the [ O 3 ] environment is significantly more pyramidal than that in the [ S 3 ] environment. In contrast, the thallium centers of the tris­(pyrazolyl)­hydroborato compounds, [Tp R,R′ ]­Tl, are more pyramidal than those of [To RBenz ]­Tl, which is in part a consequence of the fact that coordination of [Tp R,R′ ] results in the formation of 6-membered chelate rings, whereas coordination of [To RBenz ] and [Tm RBenz ] creates 8-membered rings.…”

Chemistry of the p-block elements with anionic scorpionate ligands

“…It is assumed the Tp * complex adopts an analogous structure. Finally, the three ligands also react with Me2GaCl to form complexes [Ga(RTp * )Me2], which are shown to be tetrahedral by X-ray crystallography (Figure 3), and in these compounds the non-coordinated pyrazoles are distant from the metal centre, unlike in in [Ga(Tp * [30]. The crystal structure shows it to be tetrahedrally coordinated with three nitrogen donors and the hydride ligand (Figure 4).…”