| Autor: |
Elsby MR; Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States., Kumar A; Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States., Daniels LM; Rigaku Oxford Diffraction, The Woodlands, Texas 77381, United States., Ertem MZ; Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States., Hazari N; Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States., Mercado BQ; Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States., Paulus AH; Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States. |
| Jazyk: |
angličtina |
| Zdroj: |
Inorganic chemistry [Inorg Chem] 2024 Oct 14; Vol. 63 (41), pp. 19396-19407. Date of Electronic Publication: 2024 Sep 30. |
| DOI: |
10.1021/acs.inorgchem.4c03365 |
| Abstrakt: |
Six rhenium hydride complexes, [(6,6'-R 2 -bpy)Re(CO) 3 H] (bpy = 2,2'-bipyridine, R = OEt, OMe, NHMe, Me, F, Br), were synthesized. These complexes insert CO 2 to form rhenium formate complexes of the type [(6,6'-R 2 -bpy)Re(CO) 3 {OC(O)H}]. All the rhenium formate species were characterized using X-ray crystallography, which revealed that the bpy ligand is not coplanar with the metal coordination plane containing the two nitrogen donors of the bpy ligand but tilted. A solid-state structure of [(6,6'-Me 2 -bpy)Re(CO) 3 H] determined using MicroED also featured a tilted bpy ligand. The kinetics of CO 2 insertion into complexes of the type [(6,6'-R 2 -bpy)Re(CO) 3 H] were measured experimentally and the thermodynamic hydricities of [(6,6'-R 2 -bpy)Re(CO) 3 H] species were determined using theoretical calculations. A Brønsted plot constructed using the experimentally determined rate constants for CO 2 insertion and the calculated thermodynamic hydricities for [(6,6'-R 2 -bpy)Re(CO) 3 H] revealed a linear free energy relationship (LFER) between thermodynamic and kinetic hydricity. This LFER is different to the previously determined relationship for CO 2 insertion into complexes of the type [(4,4'-R 2 -bpy)Re(CO) 3 H]. At a given thermodynamic hydricity, CO 2 insertion is faster for complexes containing a 6,6'-substituted bpy ligand. This is likely in part due to the tilting observed for systems with 6,6'-substituted bpy ligands. Notably, the 6,6'-(NHMe) 2 -bpy ligand could in principle stabilize the transition state for CO 2 insertion via hydrogen bonding. This work shows that if only the rate of CO 2 insertion into [(6,6'-(NHMe) 2 -bpy)Re(CO) 3 H] is compared to [(4,4'-R 2 -bpy)Re(CO) 3 H] systems, the increase in rate could be easily attributed to hydrogen bonding, but in fact all 6,6'-substituted systems lead to faster than expected rates. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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