Absolute rigidity is rare in the "soft"world of organometallics. Here we introduce two cyclopenta[a]triptycyl ansa-zirconocene catalysts for isotactic-selective propene polymerization, designed by means of an integrated high-throughput experimentation/quantitative structure-activity relationship modeling approach. An ultrarigid ligand precisely wrapped around the Zr center enforces an enzyme-like lock and key fit, effectively hampering undesired reactive events, even at high temperature. Stereodefective units are hardly detectable by 13C NMR in the polymer produced at 120 °C; this corresponds to an enantioselectivity exceeding 6-7 kcal/mol: i.e., less than 1 propene misinsertion every 4000 (and at room temperature, one every ∼40000!).
Ansa-Zirconocene Catalysts for Isotactic-Selective Propene Polymerization at High Temperature: A Long Story Finds a Happy Ending / Kulyabin, P. S.; Goryunov, G. P.; Sharikov, M. I.; Izmer, V. V.; Vittoria, A.; Budzelaar, P. H. M.; Busico, V.; Voskoboynikov, A. Z.; Ehm, C.; Cipullo, R.; Uborsky, D. V.. - In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. - ISSN 0002-7863. - 143:20(2021), pp. 7641-7647. [10.1021/jacs.1c03380]
Ansa-Zirconocene Catalysts for Isotactic-Selective Propene Polymerization at High Temperature: A Long Story Finds a Happy Ending
Vittoria A.Primo
;Budzelaar P. H. M.;Busico V.;Ehm C.
;Cipullo R.
Ultimo
;
2021
Abstract
Absolute rigidity is rare in the "soft"world of organometallics. Here we introduce two cyclopenta[a]triptycyl ansa-zirconocene catalysts for isotactic-selective propene polymerization, designed by means of an integrated high-throughput experimentation/quantitative structure-activity relationship modeling approach. An ultrarigid ligand precisely wrapped around the Zr center enforces an enzyme-like lock and key fit, effectively hampering undesired reactive events, even at high temperature. Stereodefective units are hardly detectable by 13C NMR in the polymer produced at 120 °C; this corresponds to an enantioselectivity exceeding 6-7 kcal/mol: i.e., less than 1 propene misinsertion every 4000 (and at room temperature, one every ∼40000!).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
