文献类型：期刊文献

英文题名：Subtle dihedral angle effect of cycloalkyl-bridged PCCP diphosphine ligands on activity in chromium-catalyzed ethylene tri-/tetramerization

作者：Zhan, Licheng[1,2,3];Rao, Xiaohan[1,2];Zhao, Xing[1,2];Sha, Feng[1,2];Wu, Xin-yan[1,2];Cui, Shicong[1,2];Zhang, Jun[1,2]

机构：[1]East China Univ Sci & Technol, Sch Chem & Mol Engn, Key Lab Adv Mat, 130 Mei Long Rd, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Inst Fine Chem, Sch Chem & Mol Engn, 130 Mei Long Rd, Shanghai 200237, Peoples R China;[3]Guangdong Acad Safety Prod & Emergency Management, Guangzhou 510000, Peoples R China

年份：2026

卷号：16

期号：2

起止页码：450

外文期刊名：CATALYSIS SCIENCE & TECHNOLOGY

收录：;EI(收录号：20255119719923);WOS:【SCI-EXPANDED(收录号:WOS:001634828800001)】；

基金：We are grateful for financial support from the National Natural Science Foundation of China (22071055), the Fundamental Research Funds for the Central Universities (222201717003).

语种：英文

外文关键词：Catalyst activity - Chromium compounds - Dihedral angle - Ligands - Phosphorus compounds - Synthesis (chemical)

摘要：Chromium complexes supported by alkyl-bridged PCCP ligands (Ph2PCH(R1)-C(R2)PPh2) demonstrate exceptional catalytic activity and selectivity in ethylene tri-/tetramerization reactions. To elucidate the influence of PCCP ligand geometry on catalytic performance, a series of bisphosphine ligands featuring five- to eight-membered cycloalkane bridges were systematically synthesized. Notably, the catalytic behavior is profoundly dependent on the ring size of the cycloalkane bridge. As the bridge cycloalkane increases in ring size, the chromium complexes exhibit a 3.4 fold enhancement in activity (from 813 kg g-1 Cr per h for the five-membered ring to 2891 kg g-1 Cr per h for the eight-membered variant) alongside a progressive improvement in alpha-olefin selectivity (total selectivity of 1-C6 and 1-C8 from 76.5% to 90.3%). Concurrently, polyethylene formation is dramatically suppressed (from 38.6% to 0.14%). Under optimal conditions, complex bearing ligand 4 achieves a peak activity of 3120 kg g-1 Cr per h with 48.9% 1-C8 selectivity, 89.9% alpha-olefin selectivity, and near-complete suppression of polymer. Structural analysis reveals a critical correlation between the ligand backbone dihedral angle and catalytic performance: smaller dihedral angles correlate with higher activity, underscoring the pivotal role of ligand structure in tuning reactivity.