Understanding the reaction mechanism of the CO2 and cyclohexene oxide copolymerization catalyzed by zinc(II) and magnesium(II) catalysts: a DFT approach

Lucas W de Lima; Sara Figueirêdo de Alcântara Morais; Ataualpa A C Braga

doi:10.1007/s00894-022-05293-7

Understanding the reaction mechanism of the CO₂ and cyclohexene oxide copolymerization catalyzed by zinc(II) and magnesium(II) catalysts: a DFT approach

J Mol Model. 2022 Sep 14;28(10):314. doi: 10.1007/s00894-022-05293-7.

Authors

Lucas W de Lima^#¹, Sara Figueirêdo de Alcântara Morais^#¹, Ataualpa A C Braga^#²

Affiliations

¹ Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Lineu Prestes Av., 748, São Paulo, 05508-900, São Paulo, Brazil.
² Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Lineu Prestes Av., 748, São Paulo, 05508-900, São Paulo, Brazil. ataualpa@iq.usp.br.

^# Contributed equally.

PMID: 36104579
DOI: 10.1007/s00894-022-05293-7

Abstract

The reaction mechanisms of carbon dioxide and cyclohexene oxide copolymerization catalyzed by four different zinc(II)-magnesium(II) (labeled as M1-M2) catalysts were computationally studied using density functional theory at the BP86-D3(BJ)/def2-TZVP/SMD//BP86-D3(BJ)/def2-SVP/SMD level of theory. The results showed that the most effective catalyst was the ZnMg system, in which poly(cyclohexene carbonate) was the preferred product, followed by the side product cis-cyclohexene carbonate. The QTAIM, NCI and ELF analysis performed to understand the role of metals in the reaction showed that ligands and substrates interact more strongly with zinc(II) centers compared to magnesium(II) centers. Furthermore, the Zn-I interaction at the M₁ position was stronger than the Mg-I interaction at the same position. All these results indicate a synergism between the metals Zn and Mg, which makes Zn(II)Mg(II) the best combination for the reaction.

Keywords: Bimetallic catalyst; CO2; DFT; ROCOP.

Abstract

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