Unconventional Stereoerror Formation Mechanisms in Nonmetallocene Propene Polymerization Systems Revealed by DFT Calculations.

Autor:	Romano E; Scuola Superiore Meridionale, Largo San Marcellino 10, 80138 Napoli, Italy., Budzelaar PHM; Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Via Cintia, 80126 Napoli, Italy., De Rosa C; Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Via Cintia, 80126 Napoli, Italy., Talarico G; Scuola Superiore Meridionale, Largo San Marcellino 10, 80138 Napoli, Italy.; Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Via Cintia, 80126 Napoli, Italy.
Jazyk:	angličtina
Zdroj:	The journal of physical chemistry. A [J Phys Chem A] 2022 Sep 15; Vol. 126 (36), pp. 6203-6209. Date of Electronic Publication: 2022 Sep 02.
DOI:	10.1021/acs.jpca.2c04935
Abstrakt:	An unconventional mechanism for the stereoerror formation in propene polymerization catalyzed by C 1 -symmetric salalen-M systems (M = Zr, Hf) is suggested by DFT calculations. While propagation happens with the ligand in its fac-mer conformation, a change of ligand wrapping mode from fac-mer to fac-fac is the main source of the lower stereoselectivities obtained with Zr and Hf. This is different for the Ti analogues, where the ligand fac - mer wrapping mode does not play a role. Activation strain analysis indicates that the preference for a chain stationary mechanism of the Zr/Hf species is due to the energy required to distort the reactants (Δ E Strain ) rather than to their mutual interaction (Δ E Int ) .
Databáze:	MEDLINE
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