Dicyanopyrazine photoredox catalysts: Correlation of efficiency with photophysics and electronic structure

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F24%3A39921723" target="_blank" >RIV/00216275:25310/24:39921723 - isvavai.cz</a>

Alternative codes found

RIV/60461373:22310/24:43929091

Result on the web

<a href="https://www.sciencedirect.com/science/article/pii/S0021951724000617" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0021951724000617</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jcat.2024.115348" target="_blank" >10.1016/j.jcat.2024.115348</a>

Result language

angličtina

Original language name

Dicyanopyrazine photoredox catalysts: Correlation of efficiency with photophysics and electronic structure

Original language description

Catalytic performance of three structurally-related dicyanopyrazine catalysts has been investigated in three photoredox transformations including deuteration of aldehydes, cross-coupling of iodo-substituted (hetero)aromatic substrates, and alpha-hydrogen abstraction from amines followed by annulation to pyrroloquinoline. Significantly different catalytic activity of the photocatalysts has been explained with the aid of electrochemical, spectroscopic, and quantum-chemical methods. Electrochemical measurements pointed to reversible oneelectron reduction of the photocatalysts affording the corresponding radical anion, and, therefore, dicyanopyrazines are principally well-suited for reductive quenching cycle. Triplet excited state turned out to be a major excited species employed in photoinduced electron transfer. The measured excited state reduction potentials (Ered* = +1.88/+1.43 V) classify the (5-methoxy)thiophene-substituted dicyanopyrazines among the organic photocatalysts with high oxidation power, which is in contrast to N,N-dimethylanilino-substituted photocatalysts. Whereas 5-methoxythiophene photocatalyst forms triplet excited state almost independently on the solvent polarity, transient absorption spectroscopy evidenced the triplet state of N,N-dimethylanilino derivative only in nonpolar media. Moreover, its subsequent reduction to the corresponding radical anion is chemically cumbersome, which contrast to facile one-electron reduction of both cyano groups of photocatalyst bearing weak 5-methoxythiophene donors. The doublet excited radical anion of the latter proved to be very powerful but short-lived reductant with Eox* = -2.84 V. Its reduction power has been demonstrated in a cross-coupling reaction involving consecutive photoinduced electron transfer to preassociated iodo(hetero)arenes. Hence, bis(5methoxythiophen-2-yl)-2,3-dicyanopyrazine can be utilized in photoredox catalysis either as powerful oxidant or reductant.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10401 - Organic chemistry

Project

<a href="/en/project/GA22-14988S" target="_blank" >GA22-14988S: DicyanoPyraZine: Versatile Tool for Photoredox Catalysis</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of Catalysis

ISSN

0021-9517

e-ISSN

1090-2694

Volume of the periodical

430

Issue of the periodical within the volume

February 2024

Country of publishing house

US - UNITED STATES

Number of pages

13

Pages from-to

115348

UT code for WoS article

001183479300001

EID of the result in the Scopus database

2-s2.0-85184598088