Synthesis and structure of trinuclear boryloxycarbyne complexes

The mu(3)-boryloxycarbyne complexes [{Fe(CO)(3)}(3){mu(3)-COBCl{NtBu(SiMe3) }}(2)] (1) and [{(eta(5)-C5H5)Ni}(3){mu(3)-COBX(NR2)}mu(3)-CO] (2a: NR2 = N tBu(SiMe3), X = Cl; 2b: NR2 = N(SiMe3)(2), X = Cl; 2c: NR2 = NMe2, X = BNMe 2Cl) were obtained reaction of the anionic complexes K-2[{Fe(CO)(3)}(3){mu( 3)-CO}(2)] and K[(eta(5)-C5H5)Ni(CO)] with the corresponding chloroboranes Cl2BNR2 {NR2 = NtBu(SiMe3), N(SiMe3)(2)}, or 1,2-dichlorodiboranes (4) B-2( NMe2)(2)Cl-2, respectively. The products are formed by a nucleophilic attac k of the CO oxygen atom at the boron centres with subsequent salt eliminati on. All compounds were characterized by IR and multinuclear NMR spectroscop y, and the structures of 1 and 2c in the solid state were determined by sin gle-crystal X-ray diffraction studies.