Metal-Ligand Cooperative Reactivity in the (pseudo)-Dearomatized PNX(P) Systems: the Influence of the Zwitterionic Form in Dearomatized Pincer Complexes

Handle URI:
http://hdl.handle.net/10754/625752
Title:
Metal-Ligand Cooperative Reactivity in the (pseudo)-Dearomatized PNX(P) Systems: the Influence of the Zwitterionic Form in Dearomatized Pincer Complexes
Authors:
Goncalves, Theo; Huang, Kuo-Wei ( 0000-0003-1900-2658 )
Abstract:
The concept of aromaticity in pincer ligands and complexes was discussed in order to provide insights into their metal-ligand cooperative activities. The aromatic PNx(P) and dearomatized PNx(P)* pincer ligands and the corresponding transition metal complexes were studied with the nucleus-independent chemical shift (NICSzz), anisotropy of the current (induced) density (ACID), isochemical shielding surfaces (ICSSzz), harmonic oscillator model of aromaticity (HOMA), MCBO, Shannon aromaticity, and natural bond order (NBO) analyses. The study on the model systems showed that for the dearomatized species the decrease of the NICS(1)zz value comes with the larger contribution of the aromatic zwitterionic mesomeric form. In all examples, the incorporation of the metal center into the pincer ligand decreases the NICS(1)zz values. The DFT calculations support the dearomatized pyridine ring in PNP* or PNN* ligand indeed being nonaromatic, in contrast to the PN3(P)* ligand which has partial aromatic character due to the larger contribution of the zwitterionic resonance structure. The difference in aromaticity between the rings contributes to the thermodynamic balance of the metal ligand cooperative reactions, changing the energetics of the process when different dearomatized pincer ligands are used. This was further exemplified by aromaticity analysis of the heterolytic hydrogen cleavage reaction of ruthenium PNN complexes of Milstein and the PN3 of Huang, with similar geometries but distinctive thermodynamic preference.
KAUST Department:
KAUST Catalysis Center (KCC); Physical Sciences and Engineering (PSE) Division
Citation:
Gonçalves TP, Huang K-W (2017) Metal–Ligand Cooperative Reactivity in the (Pseudo)-Dearomatized PNx(P) Systems: The Influence of the Zwitterionic Form in Dearomatized Pincer Complexes. Journal of the American Chemical Society 139: 13442–13449. Available: http://dx.doi.org/10.1021/jacs.7b06305.
Publisher:
American Chemical Society (ACS)
Journal:
Journal of the American Chemical Society
Issue Date:
1-Sep-2017
DOI:
10.1021/jacs.7b06305
Type:
Article
ISSN:
0002-7863; 1520-5126
Sponsors:
We acknowledge the service of NOOR 2, Shaheen 2 High Performance Computing Facilities, and financial support from King Abdullah University of Science and Technology (KAUST).
Additional Links:
http://pubs.acs.org/doi/abs/10.1021/jacs.7b06305; http://pubs.acs.org/doi/abs/10.1021/jacs.7b06305
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorGoncalves, Theoen
dc.contributor.authorHuang, Kuo-Weien
dc.date.accessioned2017-10-03T12:49:37Z-
dc.date.available2017-10-03T12:49:37Z-
dc.date.issued2017-09-01en
dc.identifier.citationGonçalves TP, Huang K-W (2017) Metal–Ligand Cooperative Reactivity in the (Pseudo)-Dearomatized PNx(P) Systems: The Influence of the Zwitterionic Form in Dearomatized Pincer Complexes. Journal of the American Chemical Society 139: 13442–13449. Available: http://dx.doi.org/10.1021/jacs.7b06305.en
dc.identifier.issn0002-7863en
dc.identifier.issn1520-5126en
dc.identifier.doi10.1021/jacs.7b06305en
dc.identifier.urihttp://hdl.handle.net/10754/625752-
dc.description.abstractThe concept of aromaticity in pincer ligands and complexes was discussed in order to provide insights into their metal-ligand cooperative activities. The aromatic PNx(P) and dearomatized PNx(P)* pincer ligands and the corresponding transition metal complexes were studied with the nucleus-independent chemical shift (NICSzz), anisotropy of the current (induced) density (ACID), isochemical shielding surfaces (ICSSzz), harmonic oscillator model of aromaticity (HOMA), MCBO, Shannon aromaticity, and natural bond order (NBO) analyses. The study on the model systems showed that for the dearomatized species the decrease of the NICS(1)zz value comes with the larger contribution of the aromatic zwitterionic mesomeric form. In all examples, the incorporation of the metal center into the pincer ligand decreases the NICS(1)zz values. The DFT calculations support the dearomatized pyridine ring in PNP* or PNN* ligand indeed being nonaromatic, in contrast to the PN3(P)* ligand which has partial aromatic character due to the larger contribution of the zwitterionic resonance structure. The difference in aromaticity between the rings contributes to the thermodynamic balance of the metal ligand cooperative reactions, changing the energetics of the process when different dearomatized pincer ligands are used. This was further exemplified by aromaticity analysis of the heterolytic hydrogen cleavage reaction of ruthenium PNN complexes of Milstein and the PN3 of Huang, with similar geometries but distinctive thermodynamic preference.en
dc.description.sponsorshipWe acknowledge the service of NOOR 2, Shaheen 2 High Performance Computing Facilities, and financial support from King Abdullah University of Science and Technology (KAUST).en
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.urlhttp://pubs.acs.org/doi/abs/10.1021/jacs.7b06305en
dc.relation.urlhttp://pubs.acs.org/doi/abs/10.1021/jacs.7b06305en
dc.titleMetal-Ligand Cooperative Reactivity in the (pseudo)-Dearomatized PNX(P) Systems: the Influence of the Zwitterionic Form in Dearomatized Pincer Complexesen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalJournal of the American Chemical Societyen
kaust.authorGoncalves, Theoen
kaust.authorHuang, Kuo-Weien
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