2,6-Di(4-t-butylphenyl)phenyl-group 13 organometallic compounds

Reaction of MX₃ (M = Al, Ga, In; X = Br, Cl) with RLi (R = 2,6-(4-t-BuC₆H₄)₂C₆H₃) affords RGaCl₂ · OEt₂, 1, RAlBr₂ · OEt₂, 2, R₂GaCl, 3, and R₃In, 4. These sterically demanding compounds have been characterized by elemental analyses, ¹H NMR spectroscopy, and single crystal X-ray diffraction. The geometry about the metal centers in 1 and 2 is best described as distorted tetrahedral while the coordination about the gallium atom in 3 is distorted trigonal planar. Compound 4, with the indium atom in a trigonal planar environment, is noteworthy as the first example of a tris(m-terphenyl)group 13 metal compound. The propeller arrangement of the three ligands in compound 4 serves to virtually encapsulate the metallic center.