Alkynylselenolatoalkylidynes:: [Mo(CSeCCR)(CO)2{HB(pzMe2)3}] (R = CMe3, SiMe3; pzMe2=3,5-Dimethylpyrazol-1-yl)

The reactions of [Mo( CCl)(CO)(2){HB(pzMe(2))(3)}] (pz = 3,5-dimethylpyrazol-1-yl) with lithium alkynylselenolates (LiSeC CR; R = CMe3, SiMe3) provide the alkynylselenolatoalkylidyne complexes [Mo( CSeC CR)(CO)(2){HB(pzMe(2))(3)}]. Cobalt carbonyl adds across the C C rather than the Mo C multiple bond to provide [Mo{ CSeCC(CMe3)Co-2(CO)(6)}(CO)(2){HB(pzMe(2))(3)}], which upon reaction with dppm affords the complex [Mo{ CSeCC(CMe3)Co-2(CO)(4)(dppm)}(CO)(2){HB(pzMe(2))(3)}] in addition to traces of the selenium extrusion product [Mo{ CCC(CMe3)Co-2(CO)(4)(dppm)}(CO)(2){HB(pzMe(2))(3)}].