One-Electron Reduction of Kinetically Stabilized Dipnictenes:  Synthesis of Dipnictene Anion Radicals

2006 ◽  
Vol 128 (38) ◽  
pp. 12582-12588 ◽  
Author(s):  
Takahiro Sasamori ◽  
Eiko Mieda ◽  
Noriyoshi Nagahora ◽  
Kazunobu Sato ◽  
Daisuke Shiomi ◽  
...  
Keyword(s):  
Electron Reduction ◽  
Anion Radicals

Electrochemical and spectroelectrochemical characterization of Cu(II) and Mn(III) tetrabutano- and tetrabenzoporphyrins containing sterically hindered meso -(2,6-difluorophenyl) substituents in nonaqueous media

2019 ◽  
Vol 23 (09) ◽  
pp. 1057-1071 ◽  
Author(s):  
Liping Wang ◽  
Yuanyuan Fang ◽  
Weijie Xu ◽  
Zhongping Ou ◽  
Karl M. Kadish
Keyword(s):  
Central Metal ◽  
Redox Potentials ◽  
Nonaqueous Media ◽  
The Third ◽  
Sterically Hindered ◽  
Electron Reduction ◽  
The Given ◽  
Spectroelectrochemical Properties ◽  
Anion Radicals

Four tetrabutano and tetrabenzoporphyrins containing sterically hindered meso-(2,6-difluorophenyl) substituents and copper(II) or manganese(III) central metal ions were synthesized and characterized as to their electrochemical and spectroelectrochemical properties in nonaqueous media. The copper(II) derivatives exhibit the expected two one-electron reductions to give [Formula: see text]-anion radicals and dianions in CH2Cl2. Electrochemical and spectroelectrochemical data suggest that a Cu(II) phlorin anion is generated from the doubly reduced Cu(II) butanoporphyrin and it is this species which undergoes the third reduction in pyridine. The first one-electron reduction of the Mn(III) porphyrins is metal-centered to give a Mn(II) compound, while the second and third reductions are macrocycle-centered to give Mn(II) porphyrin [Formula: see text]-anion radicals and dianions in both CH2Cl2 and pyridine. A Mn(II) phlorin anion is also generated from the Mn(II) dianion on the spectroelectrochemical timescale under the given solution conditions. The [Formula: see text],[Formula: see text]-butano and benzo groups have a significant effect on the measured redox potentials. Steric hindrance of the meso-(2,6-difluorophenyl) substituents also has an effect on the potential separation between the first two oxidations of the benzoporphyrins.

One-electron reduction of quinoxaline derivatives and EPR spectra of their anion radicals

1972 ◽  
Vol 5 (6) ◽  
pp. 612-615
Author(s):  
L. L. Gordienko ◽  
Yu. S. Rozum ◽  
A. G. Chukhlantseva ◽  
V. N. Rudenko
Keyword(s):  
Epr Spectra ◽  
Quinoxaline Derivatives ◽  
Electron Reduction ◽  
Anion Radicals

Resonance Raman and absorption properties of Zn(II) and Ni(II) polynitroporphyrins and their chemical reduction products

2007 ◽  
Vol 11 (09) ◽  
pp. 682-690 ◽  
Author(s):  
Sergei N. Terekhov ◽  
Gennadii N. Sinyakov ◽  
Evgeni E. Lobko ◽  
Pierrette Battiony ◽  
Pierre-Yves Turpin ◽  
...  
Keyword(s):  
Steady State ◽  
Chemical Reduction ◽  
Resonance Raman ◽  
Absorption Properties ◽  
Aryl Ring ◽  
Electron Reduction ◽  
The One ◽  
Steady State Absorption ◽  
Excited Resonance ◽  
Anion Radicals

Electron-deficient metallocomplexes of dodeca- and octanitroporphyrins produced by the introduction of 8 β-nitro substituents or 8 β-nitro and a meta-nitro substituent on each meso-aryl ring of Zn (II) and Ni (II) [meso-tetra-(2,6-dichlorophenyl)porphyrin] (Zn8, Ni8 and Zn12, Ni12, respectively) and their air-stable reduced species have been characterized by steady-state absorption and Soret-excited resonance Raman spectroscopies. One-electron reduced species of the metallocomplexes were produced by three different procedures (in deprotonated tetrahydrofuran in air ambient, in tetralhydrofuran with the addition of piperidine in air ambient, and in contact with a sodium mirror under vacuum) and demonstrated similar absorption and RR spectra. It is concluded on the basis of the RR spectra that the one-electron reduction products of the studied polynitrosubstituted metalloporphyrins are π–anion radicals in character.

Room Temperature Alkali Metal Reduction of Carbon Dioxide

2020 ◽  
Author(s):  
Lucas A. Freeman ◽  
Akachukwu D. Obi ◽  
Haleigh R. Machost ◽  
Andrew Molino ◽  
Asa W. Nichols ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Room Temperature ◽  
Chemical Reduction ◽  
Bond Cleavage ◽  
Open Shell ◽  
Metal Reduction ◽  
One Pot ◽  
Earth Abundant ◽  
Electron Reduction

The reduction of the relatively inert carbon–oxygen bonds of CO<sub>2</sub> to access useful CO<sub>2</sub>-derived organic products is one of the most important fundamental challenges in synthetic chemistry. Facilitating this bond-cleavage using earth-abundant, non-toxic main group elements (MGEs) is especially arduous because of the difficulty in achieving strong inner-sphere interactions between CO<sub>2</sub> and the MGE. Herein we report the first successful chemical reduction of CO<sub>2</sub> at room temperature by alkali metals, promoted by a cyclic(alkyl)(amino) carbene (CAAC). One-electron reduction of CAAC-CO<sub>2</sub> adduct (<b>1</b>) with lithium, sodium or potassium metal yields stable monoanionic radicals clusters [M(CAAC–CO<sub>2</sub>)]<sub>n</sub>(M = Li, Na, K, <b> 2</b>-<b>4</b>) and two-electron alkali metal reduction affords open-shell, dianionic clusters of the general formula [M<sub>2</sub>(CAAC–CO<sub>2</sub>)]<sub>n </sub>(<b>5</b>-<b>8</b>). It is notable that these crystalline clusters of reduced CO<sub>2</sub> may also be isolated via the “one-pot” reaction of free CO<sub>2</sub> with free CAAC followed by the addition of alkali metals – a reductive process which does not occur in the absence of carbene. Each of the products <b>2</b>-<b>8</b> were investigated using a combination of experimental and theoretical methods.<br>

Sign in / Sign up

Export Citation Format

Share Document