Influence of the Size of the Metallacycle of P‐NHC Mn Complexes for the Hydrogenation of Esters
Abstract
Chelate ring size is a key but underexplored parameter in the design of manganese-based hydrogenation catalysts. Here, we report the synthesis and characterization of Mn(I) NHC-phosphine complexes [Mn-5] C7 featuring a seven-membered chelate ring and their application to the hydrogenation of carboxylic esters. The N-mesityl-substituted complex [Mn-5 Mes ] C7 , with markedly improved activity relative to its five-and six-membered analogs, achieves quantitative yields of the corresponding alcohols (0.25 mol%, 2.5 mol% KHBEt 3 , 50 bar H 2 , 2-MeTHF, 100-120 °C, 5 h), including halogenated aromatic esters, aliphatic esters, and poly(ε-caprolactone), which is fully depolymerized to hexan-1-ol. Systematic comparison of the C5, C6, and C7 series by X-ray crystallography, multinuclear NMR, IR, and cyclic voltammetry shows that ring enlargement progressively increases the bite angle, reduces steric strain, and enhances electron donation at the metal, structural and electronic changes that collectively account for the improved catalytic performance.
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BibTeX
@article{pointis2026influence,
title = {{Influence of the Size of the Metallacycle of P‐NHC Mn Complexes for the Hydrogenation of Esters}},
author = {Romane Pointis and Karim Azouzi and Christian Bijani and Carine Duhayon and Laure Vendier and Olivier Reynes and David Evrard and Stéphanie Bastin and Jean‐baptiste Sortais},
journal = {Advanced Synthesis and Catalysis},
year = {2026},
month = sep,
doi = {10.1002/adsc.70760},
url = {https://hal.science/hal-05798564v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Influence of the Size of the Metallacycle of P‐NHC Mn Complexes for the Hydrogenation of Esters
AU - Romane Pointis
AU - Karim Azouzi
AU - Christian Bijani
AU - Carine Duhayon
AU - Laure Vendier
AU - Olivier Reynes
AU - David Evrard
AU - Stéphanie Bastin
AU - Jean‐baptiste Sortais
PY - 2026
DA - 2026/09/18
JO - Advanced Synthesis and Catalysis
DO - 10.1002/adsc.70760
UR - https://hal.science/hal-05798564v1
AB - Chelate ring size is a key but underexplored parameter in the design of manganese-based hydrogenation catalysts. Here, we report the synthesis and characterization of Mn(I) NHC-phosphine complexes [Mn-5] C7 featuring a seven-membered chelate ring and their application to the hydrogenation of carboxylic esters. The N-mesityl-substituted complex [Mn-5 Mes ] C7 , with markedly improved activity relative to its five-and six-membered analogs, achieves quantitative yields of the corresponding alcohols (0.25 mol%, 2.5 mol% KHBEt 3 , 50 bar H 2 , 2-MeTHF, 100-120 °C, 5 h), including halogenated aromatic esters, aliphatic esters, and poly(ε-caprolactone), which is fully depolymerized to hexan-1-ol. Systematic comparison of the C5, C6, and C7 series by X-ray crystallography, multinuclear NMR, IR, and cyclic voltammetry shows that ring enlargement progressively increases the bite angle, reduces steric strain, and enhances electron donation at the metal, structural and electronic changes that collectively account for the improved catalytic performance.
SN - 1615-4150
SN - 1615-4169
ER -