103656-16-2Relevant academic research and scientific papers
CYCLOTRIMERIZATION OF ACETYLENES CATALYZED BY (η5-CYCLOPENTADIENYL)RHODIUM COMPLEXES
Abdulla, Khalid,Booth, Brian L.,Stacey, Catherine
, p. 103 - 114 (1985)
The comparative rates of cyclotrimerization of dimethylacetylenedicarboxylate (DMAD) and hex-3-yne have been studied with the catalysts 5-C5R5)Rh(COD)> (R=H, Me, Cl; COD=cycloocta-1,5-diene), 5-C5R5)Rh(CO)2> (R=H, Me), 5-C5Me5)RhL2> (L=C2H4, PF3) and 5-C5H4PPh3)Rh(CO)2>+ PF6- under pseudo-first-order conditions.In these reactions, which all obey the rate law, rate=kobs, the rate of cyclotrimerization of DMAD decreases as the ?-acceptor strength of the cyclopentadienyl ligand increases, and this trend is reversed in reactions of hex-3-yne.The rates of cyclotrimerization also appear to vary with the nature of the ligand L (where L=C2H4, CO, PF3, 1/2COD) implying that L remains bound to the rhodium atom through the catalytic cycle.Preliminary studies have shown that in some cases selective co-oligomerization occurs with mixtures of two different acetylenes using the catalysts 5-C5H5)Rh(COD)> and 5-C9H7)Rh(COD)>.
