The role of an intramolecular hydrogen bond in the redox properties of carboxylic acid naphthoquinones.

Autor:	Guerra WD; School of Molecular Sciences, Arizona State University Tempe Arizona 85287-1604 USA amoore@asu.edu., Odella E; School of Molecular Sciences, Arizona State University Tempe Arizona 85287-1604 USA amoore@asu.edu., Cui K; Department of Chemistry, Princeton University Princeton New Jersey 08544 USA shs566@princeton.edu., Secor M; Department of Chemistry, Princeton University Princeton New Jersey 08544 USA shs566@princeton.edu., Dominguez RE; School of Molecular Sciences, Arizona State University Tempe Arizona 85287-1604 USA amoore@asu.edu., Gonzalez EJ; School of Molecular Sciences, Arizona State University Tempe Arizona 85287-1604 USA amoore@asu.edu., Moore TA; School of Molecular Sciences, Arizona State University Tempe Arizona 85287-1604 USA amoore@asu.edu., Hammes-Schiffer S; Department of Chemistry, Princeton University Princeton New Jersey 08544 USA shs566@princeton.edu., Moore AL; School of Molecular Sciences, Arizona State University Tempe Arizona 85287-1604 USA amoore@asu.edu.
Jazyk:	angličtina
Zdroj:	Chemical science [Chem Sci] 2024 Sep 20. Date of Electronic Publication: 2024 Sep 20.
DOI:	10.1039/d4sc05277c
Abstrakt:	A bioinspired naphthoquinone model of the quinones in photosynthetic reaction centers but bearing an intramolecular hydrogen-bonded carboxylic acid has been synthesized and characterized electrochemically, spectroscopically, and computationally to provide mechanistic insight into the role of proton-coupled electron transfer (PCET) of quinone reduction in photosynthesis. The reduction potential of this construct is 370 mV more positive than the unsubstituted naphthoquinone. In addition to the reversible cyclic voltammetry, infrared spectroelectrochemistry confirms that the naphthoquinone/naphthoquinone radical anion couple is fully reversible. Calculated redox potentials agree with the experimental trends arising from the intramolecular hydrogen bond. Molecular electrostatic potentials illustrate the reversible proton transfer driving forces, and analysis of the computed vibrational spectra supports the possibility of a combination of electron transfer and PCET processes. The significance of PCET, reversibility, and redox potential management relevant to the design of artificial photosynthetic assemblies involving PCET processes is discussed. Competing Interests: There are no conflicts to declare. (This journal is © The Royal Society of Chemistry.)
Databáze:	MEDLINE
Externí odkaz:	Zobrazit plný text záznamu