Insertion of the Ga(I) bis-imidinate Ga(DDP) into the metal halogen bonds of Rh(I) complexes. How electrophilic are coordinated Ga(DDP) fragments?

The reactivity of Ga(DDP) (DDP = 2-((2,6-diisopropylphenyl)amino-4-((2,6-diisopropylphenyl)imino)-2-pentene) towards the rhodium-chloride bonds of [RhCl(PPh3)(3)] and [RhCl(COE)(2)](2) (COE = cyclooctene) is investigated. Reaction of the first complex leads to [(Ph3P)(2)Rh{Ga(DDP)}(mu-Cl)] (1), exhibiting a chloride bridging the gallium and the rhodium atoms, whereas the second complex leads to a full insertion of the Ga(DDP) ligand into the Rh-Cl bond giving [(COE)(benzene)Rh{(DDP)GaCl}] (2) on coordination of the solvent C6H6. Compounds 1 und 2 readily react with the halide abstracting reagent Tl[BArF] (BArF = B[3,5-(CF3)(2)C6H3](4)), yet the products could not be isolated and characterized because of their lability. The Au(l) complex [{(DDP)Ga}Au{Ga(DDP)}Cl] reacts with Na[BArF] giving the linear, symmetric cationic complex [{(DDP)Ga center dot THF}(2)Au][BArF] (3 center dot 2THF), exhibiting two THF molecules coordinated to the Ga(DDP) moieties.