Reactions of the Tetraalkyldigallium Compound R2Ga–GaR2 [R = CH(SiMe3)2] with Acidic Reagents, Retention vs. Cleavage of the Ga–Ga Bond and Formation of Supramolecular Aggregates via Hydrogen Bonding

Abstract

AbstractTreatment of the tetraalkyldigallium compound R2Ga–GaR2 [1, R = CH(SiMe3)2] with two equivalents of carboxylic acid hydrazides (4‐trifluormethylbenzhydrazide, 2‐fuoric acid hydrazide and 2‐chlor‐6‐hydrazineisonicotinic acid hydrazide) afforded new digallium species by the release of CH2(SiMe3)2. The intact Ga–Ga bonds of the products (2 to 4) are terminally coordinated by two chelating hydrazide ligands via NH2 groups and the carbonyl oxygen atoms. Interesting supramolecular aggregates are formed in the solid state, which contain dimeric formula units of the digallium species connected via a complex system of hydrogen bonds. Two ether molecules are additionally coordinated to terminal N–H functions. Phenylphosphinic acid and 1 gave the analogous substituent replacement reaction with the formation of a dimeric tetragallium compound (5). Its two Ga–Ga bonds are in a perpendicular arrangement with four phosphinate ligands in the bridging positions. Oxidation of the gallium atoms and insertion of an N=N double bond into the Ga–Ga bond was observed upon treatment of 1 with azodicarbonamide.