Quenching Studies of the Excited State of (4,7-Diphenylphenanthroline)(1-(ethoxycarbonyl)-1- cyanoethylene-2,2-dithiolato)platinum(II), Pt(Ph2phen)(ecda), by Aromatic Amines and Metallocenes and Determination of Its Excited-State Reduction Potential

1994 ◽  
Vol 33 (9) ◽  
pp. 1886-1890 ◽  
Author(s):  
Joanne M. Bevilacqua ◽  
Richard Eisenberg
Keyword(s):  
Excited State ◽  
Aromatic Amines ◽  
Reduction Potential ◽  
State Reduction

scholarly journals N-Arylphenothiazines as strong donors for photoredox catalysis – pushing the frontiers of nucleophilic addition of alcohols to alkenes

2019 ◽  
Vol 15 ◽  
pp. 52-59 ◽  
Author(s):  
Fabienne Speck ◽  
David Rombach ◽  
Hans-Achim Wagenknecht
Keyword(s):  
Excited State ◽  
Nucleophilic Addition ◽  
Reduction Potential ◽  
Phenyl Group ◽  
Addition Product ◽  
Electrochemical Characteristics ◽  
Photoredox Catalysis ◽  
Reaction Conditions ◽  
State Reduction ◽  
Reducing Properties

A new range of N-phenylphenothiazine derivatives was synthesized as potential photoredox catalysts to broaden the substrate scope for the nucleophilic addition of methanol to styrenes through photoredox catalysis. These N-phenylphenothiazines differ by their electron-donating and electron-withdrawing substituents at the phenyl group, covering both, σ and π-type groups, in order to modulate their absorbance and electrochemical characteristics. Among the synthesized compounds, alkylaminylated N-phenylphenothiazines were identified to be highly suitable for photoredox catalysis. The dialkylamino substituents of these N-phenylphenothiazines shift the estimated excited state reduction potential up to −3.0 V (vs SCE). These highly reducing properties allow the addition of methanol to α-methylstyrene as less-activated substrate for this type of reaction. Without the help of an additive, the reaction conditions were optimized to achieve a quantitative yield for the Markovnivkov-type addition product after 20 h of irradiation.

scholarly journals Hydricity, electrochemistry, and excited-state chemistry of Ir complexes for CO2 reduction

2017 ◽  
Vol 198 ◽  
pp. 301-317 ◽  
Author(s):  
Gerald F. Manbeck ◽  
Komal Garg ◽  
Tomoe Shimoda ◽  
David J. Szalda ◽  
Mehmed Z. Ertem ◽  
...  
Keyword(s):  
Excited State ◽  
Dft Calculations ◽  
Density Functional ◽  
Reduction Potential ◽  
Co2 Reduction ◽  
Theoretical Data ◽  
Functional Theory ◽  
State Reduction ◽  
State Potential ◽  
Derivatives Of

We prepared electron-rich derivatives of [Ir(tpy)(ppy)Cl]+ with modification of the bidentate (ppy) or tridentate (tpy) ligands in an attempt to increase the reactivity for CO2 reduction and the ability to transfer hydrides (hydricity). Density functional theory (DFT) calculations reveal that complexes with dimethyl-substituted ppy have similar hydricities to the non-substituted parent complex, and photocatalytic CO2 reduction studies show selective CO formation. Substitution of tpy by bis(benzimidazole)-phenyl or -pyridine (L3 and L4, respectively) induces changes in the physical properties that are much more pronounced than from the addition of methyl groups to ppy. Theoretical data predict [Ir(L3)(ppy)(H)] as the strongest hydride donor among complexes studied in this work, but [Ir(L3)(ppy)(NCCH3)]+ cannot be reduced photochemically because the excited state reduction potential is only 0.52 V due to the negative ground state potential of −1.91 V. The excited state of [Ir(L4)(ppy)(NCCH3)]2+ is the strongest oxidant among complexes studied in this work and the singly-reduced species is formed readily upon photolysis in the presence of tertiary amines. Both [Ir(L3)(ppy)(NCCH3)]+ and [Ir(L4)(ppy)(NCCH3)]2+ exhibit electrocatalytic current for CO2 reduction. While a significantly greater overpotential is needed for the L3 complex, a small amount of formate (5–10%) generation in addition to CO was observed as predicted by the DFT calculations.

Nanomolar Determination of Nitrofurans in Water via Excited-State Inter-Ligand Proton Transfer

2021 ◽  
pp. 338905
Author(s):  
Xiaojun Zhang ◽  
Lina Zhao ◽  
Xiaomeng Jin ◽  
Zijun Zhang ◽  
Yuxin Li
Keyword(s):  
Excited State ◽  
Proton Transfer
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