abstracts - Институт катализа им. Г.К. Борескова

OP-III-40similar π-alkyne CpNi( PhC ≡ CPh ) 2 forms. It has no isomers and significantly more stable intime contrary to the CpNi( PhC ≡ CH ) 2 complex.It was established that when phenylacetylene is taken in an excess relatively to theCpNi(PPh 3 ) 2 complex (molar ratio PA/Ni = 200) the monomer is actively oligomerized atambient temperature to give largely cyclic trimers (predominantly 1,2,4-triphenylbenzene)and linear oligomers containing, on average, 9-10 monomeric units. The reaction productswere characterized by NMR ( 13 С and 1 Н) and mass spectra. A proportional dependencebetween the oligomerization activity and the concentration of the π-alkyne complexCpNi( PhC ≡ CH ) 2 in the system was found. It was shown that the activity of the catalyst,monomer conversion, and the yield of the products are essentially temperature dependent. Thecondition for the 97% yield of 1,2,4-triphenylbenzene were found.In the similar conditions for diphenylacetylene, when it is an excess relative to CpNi(PPh 3 ) 2 ,oligomerization is almost unfeasible. Related regularities for the reactions of PA and DPAwith the complexes CpNi(bipy) and CpNi(COD) were found. Schemes for the cyclictrimerization and linear oligomerization by the Ni(I) π-alkyne complexes were proposed.The work is financially supported by the funds NWO (the Netherlands) and RFBR (Russia)(international grant # 047.015.014).References:[1] Pasynkiewicz S., Olędzka E., Pietrzykowski A. // J. Mol. Catal. A. 224 (2004) 117.[2] Pasynkiewicz S., Pietrzykowski A. // Coord. Chem. Rev. 231 (2002) 199.414