Theoretical Investigation of a Parallel Catalytic Cycle in CO2 Hydrogenation by (PNP)IrH3
2015 (English)In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 34, no 20, 4932-4940 p.Article in journal (Refereed) Published
The (PNP)IrH3 (2,6-bis(diisopropylphosp-hinomethyl)pyridine iridium trihydride) complex by Nozaki is a highly active and selective catalyst for CO2 hydrogenation to formic acid in aqueous KOH. Previous theoretical investigations found that regeneration of the catalyst is the rate-determining step in this reaction. In the current article we present results from a computational study using density func- theory in order to consider the possibility of sequential insertion of two CO2 molecules in two Ir-H bonds before the reaction with hydrogen. We found that insertion of a second CO2 molecule is indeed possible; moreover, this sequential insertion allows formation of a more electrophilic iridium mono-hydride intermediate, and thereby the process of H-2 cleavage is facilitated. In addition, we considered the influence of ligands coplanar with the PNP ligand on the energy of CO2 insertion into the (PNP)IrH2X complex and found that sigma- and pi-donating ligands promote the reaction.
Place, publisher, year, edition, pages
2015. Vol. 34, no 20, 4932-4940 p.
IdentifiersURN: urn:nbn:se:kth:diva-177955DOI: 10.1021/acs.organomet.5b00448ISI: 000363996300019ScopusID: 2-s2.0-84945954442OAI: oai:DiVA.org:kth-177955DiVA: diva2:876351
QC 201512032015-12-032015-11-302015-12-03Bibliographically approved