Symmetrical Bis(acetylido)ruthenium(II) Complexes

Symmetrical, mononuclear bis(acetylido)ruthenium(II) complexes were prepared by the reaction of [trans-RuMe(2)(dmpe)(2)] [dmpe = 1,2-bis(dimethylphosphanyl)ethane] with terminal alkynes. The complexes were characterised by multinuclear NMR spectroscopy and X-ray crystallography. In some cases, the complexes catalyse the head-to-head dimerisation of terminal alkynes to yield organic butenynes. The regiochemistry of this dimerisation depends on the solvent used; methanol results in the isolation of (Z)-butenynes, whereas toluene gives predominantly (E) isomers.