Synthesis of two new group 13 benzoato–chloro complexes: A structural study of gallium and indium chelating carboxylates

Two new heteroleptic chelated-benzoato gallium (III) and indium (III) complexes have been prepared and structurally characterized. The molecular structures of [GaCl2(4-Mepy)2(O2CPh)]·4-Mepy (1) and [InCl(4-Mepy)2(O2CPh)2]·4-Mepy (2) have been determined by single-crystal X-ray diffraction. The gallium compound (1) is a distorted octahedron with cis-chloride ligands co-planar with the chelating benzoate and the 4-methylpyridines trans to each other. This is the first example of a Ga(III) structure with a chelating benzoate. The indium compound (2) is a distorted pentagonal bipyramid with two chelating benzoates, one 4-methylpyridine in the plane and a chloride trans to the other 4-methylpyridine. The indium bis-benzoate is an unusual example of a seven-coordinate structure with classical ligands. Both complexes, which due to the chelates, could also be described as pseudo-trigonal bipyramidal, include a three-bladed motif with three roughly parallel aromatic rings that along with a solvent of crystallization and electron-withdrawing chloride ligand(s) stabilize the solid-state structures.

Graphical abstractORTEP diagram and atomic labeling scheme of first coordination sphere of [GaCl2(O2CPh)(4-Mepy)2]·4-Mepy (1) (hydrogen atoms and the co-crystallized picoline not shown for clarity) and ORTEP diagram and atomic labeling scheme of first coordination sphere of [InCl(O2CPh)2(4-Mepy)2]·(4-Mepy) (2) (hydrogen atoms and the co-crystallized picoline not shown for clarity).Figure optionsDownload full-size imageDownload as PowerPoint slide