Synthesis and Structure of the Neutral Three-Coordinate Gallium Selenolate Ga[Se(2,4,6-t-Bu₃C₆H₂)]₃ and the Monomeric Lithium Selenolate Li(THF)₃Se(2,4,6-t-Bu₃C₆H₂)

The homoleptic gallium selenolate Ga[Se(2,4,6-t-Bu₃C₆H₂)₃ has been synthesized by the reaction of GaCl₃ with 3 equiv of LiSeMes (Mes = 2,4,6-t-Bu₃C₆H₂) in toluene. It was characterized by ¹H NMR and infrared spectroscopy and by X-ray crystallography. The gallium center has a three-coordinate, almost planar, coordination with Ga-Se bond lengths of nearly 2.324 Å. The precursor lithium selenolate species Li(THF)₃SeMes was also crystallized and structurally characterized. Like its sulfur analogue, it possesses a monomeric structure with the Li center bound to three THF molecules and a selenium in a pseudotetrahedral manner. The Li-Se distance is near 2.57 Å and the LiSeC angle is about 101.9°. Crystal data with Mo Kα (λ = 0.71069 Å) radiation at 130 K: 1, Ga[Se(2,4,6-t-Bu₃C₆H₂)]·₃2PhMe, a = 14.523 (3) Å, b = 14.925 (6) Å, c = 16.651 (3) Å, α = 85.92 (3)°, β = 83.50 (2)°, γ = 61.39 (2)°, Z = 2, triclinic, space group [formula omited], R = 0.065; 2 Li(THF)₃Se(2,4,6-í-Bu₃C₆H₂), a = 10.758 (5) Å, b = 18.003 (6) Å, c = 17.954 (5) Å, α = 62.50 (2)°, β = 89.61 (3)°, γ = 87.91 (3)°, Z = 4 (two independent molecules), triclinic, space group [formula omited], R = 0.054.