Summary Selective linear codimerization of terminal linear codimerization of terminal acetylenes with buta- 1,3- acetylenes and buta- 1,3-diene catalysed by the first diene catalysed by a dihydridotetrakis( trialkylphosphine) - example of a dihydridotetrakis(trialky1phosphine) - ruthenium complex. ruthenium complex is reported. ... RuH,(PBu;),t (0-1-0.2 mmol), benzene (5 an3), buta- 1,3-diene (20 mmol) and the aliphatic terminal acetylenes