Synthesis and characterization of the unusual cluster [Ni2(GaAr′)2(η1:η1-μ2-C2H4)]: Ready addition of ethylene to Ni(COD)(GaAr′)2 at 25 °C and 1 atmosphere

The nickel (0) compound Ni(COD)(GaAr′)2 (Ar′ = C6H3–2,6-(C6H3-2,6-i-Pr2)2), 1, was synthesized by the reaction of Ni(COD)2 (COD = 1,5-cyclooctadiene) with (GaAr′)2. Compound 1 reacted with ethylene at 25 °C and at 1 atm pressure to give the bimetallic cluster [Ni2(GaAr′)2(η1:η1-μ2-C2H4)], 2, through the incorporation of one molecule of ethylene and displacement of COD. The structure of 2 featured an unusual Ni2Ga2C2 core bicyclic structure in which the C2H4 moiety bridges the Ga···Ga edge of a Ga2Ni2 tetrahedron. The galliums each carry an η1-bonded Ar′ substituent which complexes the nickel atom by an η6–π interaction with one of its flanking Ar’ rings.