Computational Transition-State Design Provides Experimentally Verified Cr(P,N) Catalysts for Control of Ethylene Trimerization and Tetramerization

Abstract

Computational design of molecular homogeneous organometallic catalysts followed by experimental realization remains a significant challenge. Here, we report the development and use of a density functional theory transition-state model that provided quantitative prediction of molecular Cr catalysts for controllable selective ethylene trimerization and tetramerization. This computational model identified a general class of phosphine monocyclic imine (P,N)-ligand Cr catalysts where changes in the ligand structure control 1-hexene versus 1-octene selectivity. Experimental ligand and catalyst synthesis as well as reaction testing quantitatively confirmed predictions.

Computational Ligand Descriptors for Catalyst Design

“…The development of homogeneous (organometallic) catalysts has turned a significant corner in the last decade: not only does the field now make frequent use of computational mechanistic studies to confirm hypotheses about likely reaction pathways, [1][2][3][4][5][6][7][8] but researchers have also embraced data-led approaches, combining large-scale experimentation with suitable descriptors to fit statistical models, for the discovery, optimisation, and indeed design of catalysts for a broad range of reactions. [9][10][11][12][13][14][15] This should not come as a surprise, as it builds on a long tradition of using stereoelectronic parameters, Tolman's perhaps most prominently among them, 16 in this field.…”

Machine learning dihydrogen activation in the chemical space surrounding Vaska's complex

“…An alternative to experimental HTS is the use of virtual screening (VS) methods, in which both the descriptors and the target property (e.g., catalytic activity or selectivity) are computed. [40][41][42][43][44] The application of VS to transition metal catalysis is encumbered by the need for accurate results on thousands of systems. The proper description of chemical reactivity requires the use of quantum chemistry (QC) methods such as density functional theory (DFT), which has a computational cost that quickly becomes prohibitive.…”

Chromium Complexes Supported by Phenyl Ether‐Pyrazolyl [N,O] Ligands as Catalysts for the Oligo‐ and Polymerization of Ethylene

“…[ 1–8 ] LAOs are generally produced with a broad range of olefins from C 4 to C 20 featured by Schulz‐Flory distributions manufactured by Shell, Ineos, SABIC, and Chevron‐Phillips. [ 9–12 ] Among all the transition‐metal‐based catalysts, chromium catalysts have proven to be the most promising candidates for selective ethylene oligomerization. [ 13–16 ] In this way, significant efforts have been dedicated to the synthesis of new families of ligands based on a wide variety of donor‐group combinations aiming to generate more efficient chromium catalyst systems that are capable of selectively forming α‐olefins with high productivities.…”