U.S. Department of Energy Office of Scientific and Technical Information
Carbon Dioxide Insertion into Rhenium Hydrides as a Probe for the Impact of Solvent on Linear Free Energy Relationships between Thermodynamic and Kinetic Hydricity
The kinetics of CO2 insertion into electronically different Re(Rbpy)(CO)3H (Rbpy = 4,4'-R-2,2'- bipyridine; R = OMe, tBu, Me, H, Br, COOMe, CF3) complexes to form Re(Rbpy)(CO)3{OC(H)O} compounds were determined in acetone, dimethylacetamide (DMAc), dimethylformamide (DMF), dimethylsulfoxide (DMSO), and 3-methoxypropionitrile (3-MPN) and compared with previous data in acetonitrile (MeCN). The rates of CO2 insertion for any one complex of the type Re(Rbpy)(CO)3H in different solvents correlates with the Dimroth-Reichardt (ET(30)) solvent parameter. Hammett plots in each solvent indicate that insertion reactions are faster for bpy ligands with electron-donating groups. There is, however, no correlation between the slope of the Hammett plot in different solvents and any common solvent parameter. Similarly, the enthalpies and entropies of activation and kinetic isotope effects associated with CO2 insertion into Re(bpy)(CO)3H in different solvents do not correlate with any common solvent parameters. Theoretical calculations were used to determine the relative thermodynamic hydricities of Re(Rbpy)(CO)3H type complexes in MeCN, acetone, DMF, and DMSO and in each solvent complexes with more electron-donating substituents on the bpy ligand are stronger hydride donors. Linear Free Energy Relationships (LFERs) between calculated thermodynamic and experimental kinetic hydricity, as measured through CO2 insertion reactions, were observed in MeCN, acetone, DMF, and DMSO. Furthermore, the slopes of the LFERs correlate with the dielectric constant of the solvent. Overall, this work provides fundamental information about the thermodynamics and kinetics of hydride transfer reactions in different solvents, which is valuable for catalyst design.
Elsby, Matthew R., et al. "Carbon Dioxide Insertion into Rhenium Hydrides as a Probe for the Impact of Solvent on Linear Free Energy Relationships between Thermodynamic and Kinetic Hydricity." Organometallics, vol. 42, no. 20, Oct. 2023. https://doi.org/10.1021/acs.organomet.3c00333
Elsby, Matthew R., Espinosa, Matthew R., Ertem, Mehmed Z., Deziel, Anthony P., Hazari, Nilay, Miller, Alexander J. M., Paulus, Alexandra H., & Pecoraro, Matthew V. (2023). Carbon Dioxide Insertion into Rhenium Hydrides as a Probe for the Impact of Solvent on Linear Free Energy Relationships between Thermodynamic and Kinetic Hydricity. Organometallics, 42(20). https://doi.org/10.1021/acs.organomet.3c00333
Elsby, Matthew R., Espinosa, Matthew R., Ertem, Mehmed Z., et al., "Carbon Dioxide Insertion into Rhenium Hydrides as a Probe for the Impact of Solvent on Linear Free Energy Relationships between Thermodynamic and Kinetic Hydricity," Organometallics 42, no. 20 (2023), https://doi.org/10.1021/acs.organomet.3c00333
@article{osti_2283306,
author = {Elsby, Matthew R. and Espinosa, Matthew R. and Ertem, Mehmed Z. and Deziel, Anthony P. and Hazari, Nilay and Miller, Alexander J. M. and Paulus, Alexandra H. and Pecoraro, Matthew V.},
title = {Carbon Dioxide Insertion into Rhenium Hydrides as a Probe for the Impact of Solvent on Linear Free Energy Relationships between Thermodynamic and Kinetic Hydricity},
annote = {The kinetics of CO2 insertion into electronically different Re(Rbpy)(CO)3H (Rbpy = 4,4'-R-2,2'- bipyridine; R = OMe, tBu, Me, H, Br, COOMe, CF3) complexes to form Re(Rbpy)(CO)3{OC(H)O} compounds were determined in acetone, dimethylacetamide (DMAc), dimethylformamide (DMF), dimethylsulfoxide (DMSO), and 3-methoxypropionitrile (3-MPN) and compared with previous data in acetonitrile (MeCN). The rates of CO2 insertion for any one complex of the type Re(Rbpy)(CO)3H in different solvents correlates with the Dimroth-Reichardt (ET(30)) solvent parameter. Hammett plots in each solvent indicate that insertion reactions are faster for bpy ligands with electron-donating groups. There is, however, no correlation between the slope of the Hammett plot in different solvents and any common solvent parameter. Similarly, the enthalpies and entropies of activation and kinetic isotope effects associated with CO2 insertion into Re(bpy)(CO)3H in different solvents do not correlate with any common solvent parameters. Theoretical calculations were used to determine the relative thermodynamic hydricities of Re(Rbpy)(CO)3H type complexes in MeCN, acetone, DMF, and DMSO and in each solvent complexes with more electron-donating substituents on the bpy ligand are stronger hydride donors. Linear Free Energy Relationships (LFERs) between calculated thermodynamic and experimental kinetic hydricity, as measured through CO2 insertion reactions, were observed in MeCN, acetone, DMF, and DMSO. Furthermore, the slopes of the LFERs correlate with the dielectric constant of the solvent. Overall, this work provides fundamental information about the thermodynamics and kinetics of hydride transfer reactions in different solvents, which is valuable for catalyst design.},
doi = {10.1021/acs.organomet.3c00333},
url = {https://www.osti.gov/biblio/2283306},
journal = {Organometallics},
issn = {ISSN 0276-7333},
number = {20},
volume = {42},
place = {United States},
publisher = {American Chemical Society},
year = {2023},
month = {10}}
Brookhaven National Laboratory (BNL), Upton, NY (United States); University of North Carolina at Chapel Hill, NC (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); National Science Foundation (NSF); Natural Sciences and Engineering Research Council of Canada (NSERC)