649561-75-1Relevant academic research and scientific papers
Selective head-to-tail dimerization of phenylacetylene catalyzed by a diruthenium μ-methylene complex
Gao, Yuan,Puddephatt, Richard J.
, p. 101 - 106 (2003)
The μ-methylene complex [Ru2(μ-CH2)(CO) 4(μ-dppm)2] (1) in toluene solution at 75°C is the first known catalyst for the selective dimerization of PhC≡CH or of PhC≡CD to give the head-to-tail dimer PhC≡CC(Ph)=CH2 or PhC≡CC(Ph)=CD2 respectively, probably by a mechanism involving alkenyl-alkynyl group coupling at the diruthenium center. After many turnovers, a new diruthenium complex was detected and identified as [Ru2{μ- η2-PhCCH}(CO)4(μ-dppm)2] (2) which was not an active catalyst for the dimerization reaction, and the organic product PhCCMe was also detected at this stage. Complex 2 was prepared more readily by reaction of PhCCH with [Ru2(μ-CO)(CO)4(μ-dppm) 2] (3) in toluene at 75°C. The reaction of 1 with a large excess of PhCCH gave further oligomerization and the major products were identified as an octamer and hexamer of PhCCH. Complex 1 was a catalyst for the dimerization of 1-hexyne to a mixture of dimerization products E-BuC≡C-CH=CHBu and BuC≡C-C(Bu)=CH2 in a ratio of about 2:1, and also for polymerization of HCCH, but it failed to react with the alkynes PhCCMe, PhCCPh or 3-hexyne at 75°C in toluene.
