| Autor: |
Léonard NG; Department of Chemistry, University of California, Irvine, California 92697, United States., Chantarojsiri T; Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand., Ziller JW; Department of Chemistry, University of California, Irvine, California 92697, United States., Yang JY; Department of Chemistry, University of California, Irvine, California 92697, United States.; Pacific Northwest National Laboratory, Richland, Washington 99352, United States. |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of the American Chemical Society [J Am Chem Soc] 2022 Feb 02; Vol. 144 (4), pp. 1503-1508. Date of Electronic Publication: 2022 Jan 18. |
| DOI: |
10.1021/jacs.1c09583 |
| Abstrakt: |
Local electric fields can alter energy landscapes to impart enhanced reactivity in enzymes and at surfaces. Similar fields can be generated in molecular systems using charged functionalities. Manganese(V) salen nitrido complexes (salen = N , N '-ethylenebis(salicylideneaminato)) appended with a crown ether unit containing Na + ( 1-Na ), K + , ( 1-K ), Ba 2+ ( 1-Ba ), Sr 2+ ( 1-Sr ), La 3+ ( 1-La ), or Eu 3+ ( 1-Eu ) cation were investigated to determine the effect of charge on p K a , E 1/2 , and the net bond dissociation free energy (BDFE) of N-H bonds. The series, which includes the manganese(V) salen nitrido without an appended crown, spans 4 units of charge. Bounds for the p K a values of the transient imido complexes were used with the Mn(VI/V) reduction potentials to calculate the N-H BDFEs of the imidos in acetonitrile. Despite a span of >700 mV and >9 p K a units across the series, the hydrogen atom BDFE only spans ∼6 kcal/mol (between 73 and 79 kcal/mol). These results suggest that the incorporation of cationic functionalities is an effective strategy for accessing wide ranges of reduction potentials and p K a values while minimally affecting the BDFE, which is essential to modulating electron, proton, or hydrogen atom transfer pathways. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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