Halogen Radical Abstraction From Organotransition-Metal Complexes Using The Cobalt(II) Complex [Co(DmgH)2(PY)](DmgH2 = dimethylglyoxime). Part 1. A New Synthesis of [M2(CO)2n-(n5-C5H4R)2](M = Fe, n = 2, R = H or Me; Mo, n = 3, R = H or Me)

Abstract The complexes [MX(CO)n(n 5-C5H4R)] {M = Fe, n = 2; X = Br (R = H or Me) or I(R = H only); M = Mo, n = 3, X = Cl, (R = H or Me)} react with [Co(DmgH)2(py)] (DmgH2 = dimethylglyoxime) to afford [M2(CO)2n(n 5-C5H4R)2] in good yield and the cobalt(III) complex [CoX(DmgH)2(py)]. It is likely that these reactions occur by halogen radical abstraction from [MX(CO)n(n 5-C5H4R)] to give initially the 17 electron complexes [M(CO)n(n 5-C5H4R)] which rapidly dimerise to afford [M2(CO)2n(n 5-C5H4R)2].