Rationalizing the catalytic performance of Cr(III) complexes stabilized with alkylphosphanyl PNP ligands for selective ethylene tri-/tetramerization: a DFT study

• Published in: Theoretical chemistry accounts 2022-04, Vol.141 (4), Article 25
• Main Authors: Fan, Haonan, Alam, Fakhre, Hao, Biaobiao, Ma, Jing, Zhang, Jingyi, Ma, Zhi, Jiang, Tao
• Format: Article
• Language: English
• Subjects: Atomic/Molecular Structure and Spectra; Byproducts; Chemistry; Chemistry and Materials Science; Density functional theory; Ethylene; Inorganic Chemistry; Mathematical analysis; Organic Chemistry; Physical Chemistry; Regular Article; Selectivity; Theoretical and Computational Chemistry
• ISSN: 1432-881X; 1432-2234
• DOI: 10.1007/s00214-022-02887-5

The effect of alkylphosphanyl substitutions on the PNP scaffold toward ethylene tri-/tetramerization has been explained using density functional theory (DFT). Our calculations show that different alkylphosphanyl substitutions considerably influence the catalytic environment and thus affect the catalytic performance of alkylphosphanyl PNP/Cr system. Comparing the rate-determining steps (RDSs) of all precatalysts 1–9, we have rationalized the product selectivity. The reactivity of precatalysts 5–6 {Ph 2 PN(cyclopentyl)PR 2 , 5, R = Et; 6, R =  i Pr} based systems was rationalized by frontier orbital theory. In addition, we further calculated the cyclic by-product paths of precatalysts 5–6 based systems, and the results show that the precatalyst 6 based system offers a high energy barrier toward the formation of cyclic C 6 by-products and therefore produce a small amount of these products.