Redox Properties of Structural Fe in Clay Minerals. 2. Electrochemical and Spectroscopic Characterization of Electron Transfer Irreversibility in Ferruginous Smectite, SWa-1

2012 ◽  
Vol 46 (17) ◽  
pp. 9369-9377 ◽  
Author(s):  
Christopher A. Gorski ◽  
Laura Klüpfel ◽  
Andreas Voegelin ◽  
Michael Sander ◽  
Thomas B. Hofstetter
Keyword(s):  
Electron Transfer ◽  
Clay Minerals ◽  
Spectroscopic Characterization ◽  
Redox Properties ◽  
Ferruginous Smectite

Combined spectroscopic characterization of electron transfer at hybrid CuPcF16/GaAs semiconductor interfaces

2008 ◽  
Vol 19 (42) ◽  
pp. 424010 ◽  
Author(s):  
Juan Cabanillas-Gonzalez ◽  
Hans-Joachim Egelhaaf ◽  
Alberto Brambilla ◽  
Paolo Sessi ◽  
Lamberto Duò ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Spectroscopic Characterization ◽  
Semiconductor Interfaces

scholarly journals A haloarchaeal ferredoxin electron donor that plays an essential role in nitrate assimilation

2011 ◽  
Vol 39 (6) ◽  
pp. 1844-1848 ◽  
Author(s):  
Basilio Zafrilla ◽  
Rosa María Martínez-Espinosa ◽  
María José Bonete ◽  
Julea N. Butt ◽  
David J. Richardson ◽  
...  
Keyword(s):  
Essential Role ◽  
Inorganic Nitrogen ◽  
Nitrate Assimilation ◽  
Spectroscopic Characterization ◽  
Redox Properties ◽  
Nitrite Reduction ◽  
Plant Type ◽  
Uv Visible ◽  
Nitrate And Nitrite

In the absence of ammonium, many organisms, including the halophilic archaeon Haloferax volcanii DS2 (DM3757), may assimilate inorganic nitrogen from nitrate or nitrite, using a ferredoxin-dependent assimilatory NO3−/NO2− reductase pathway. The small acidic ferredoxin Hv-Fd plays an essential role in the electron transfer cascade required for assimilatory nitrate and nitrite reduction by the cytoplasmic NarB- and NirA-type reductases respectively. UV–visible absorbance and EPR spectroscopic characterization of purified Hv-Fd demonstrate that this protein binds a single [2Fe–2S] cluster, and potentiometric titration reveals that the cluster shares similar redox properties with those present in plant-type ferredoxins.

scholarly journals Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

2013 ◽  
Vol 9 ◽  
pp. 800-808 ◽  
Author(s):  
Maurizio Fagnoni ◽  
Stefano Protti ◽  
Davide Ravelli ◽  
Angelo Albini
Keyword(s):  
Electron Transfer ◽  
Spectroscopic Characterization ◽  
Secondary Amines ◽  
Radical Anions ◽  
Radical Intermediates ◽  
Ipso Substitution ◽  
Back Electron Transfer ◽  
Anthracene Derivatives ◽  
Litmus Test

Steady-state irradiation in neat acetonitrile of some aromatic nitriles, imides and esters (10−5–10−3 M solution) in the presence of tertiary amines allowed the accumulation of the corresponding radical anions, up to quantitative yield for polysubstituted benzenes and partially with naphthalene and anthracene derivatives. The condition for such an accumulation was that the donor radical cation underwent further evolution that precluded back electron transfer and any chemical reaction with the radical anion. In fact, no accumulation occurred with 1,4-diazabicyclo[2.2.2]octane (DABCO), for which this condition is not possible. The radical anions were produced from benzene polyesters too, but decomposition began early. Ipso substitution was one of the paths with secondary amines and the only reaction with tetrabutylstannane. The results fully support the previously proposed mechanism for electron transfer (ET) mediated photochemical alkylation of aromatic acceptors via radical ions and radical intermediates.

scholarly journals Stepwise N–H bond formation from N2-derived iron nitride, imide and amide intermediates to ammonia

2016 ◽  
Vol 7 (9) ◽  
pp. 5736-5746 ◽  
Author(s):  
K. Cory MacLeod ◽  
Sean F. McWilliams ◽  
Brandon Q. Mercado ◽  
Patrick L. Holland
Keyword(s):  
Electron Transfer ◽  
Bond Formation ◽  
Iron Complexes ◽  
Spectroscopic Characterization ◽  
Iron Nitride ◽  
Proton Coupled Electron Transfer

The pathway from N2to NH3at low-coordinate iron complexes is shown through crystallographic and spectroscopic characterization of intermediates, including bridging nitride, imide, and amides. Proton-coupled electron transfer plays a key role in the transformations.

scholarly journals Electrochemical and Spectroscopic Characterization of Aluminium(III)-para-methyl-meso-tetraphenylporphyrin Complexes Containing Substituted Salicylates as Axial Ligands

2013 ◽  
Vol 2013 ◽  
pp. 1-10
Author(s):  
Gauri D. Bajju ◽  
Deepmala ◽  
Sunil Kumar Anand ◽  
Sujata Kundan ◽  
Narinder Singh
Keyword(s):  
Spectroscopic Characterization ◽  
Redox Properties ◽  
Proton Nuclear Magnetic Resonance ◽  
Spectroscopic Techniques ◽  
Axial Coordination ◽  
H Nmr ◽  
Axial Ligands ◽  
Reduction Mechanisms ◽  
C Nmr

A series of aluminium(III)-p-methyl-meso-tetraphenylporphyrin (p-CH3TPP-Al(III)) containing axially coordinated salicylate anion [p-CH3TPP-Al-X)], where X = salicylate (SA), 4-chlorosalicylate (4-CSA), 5-chlorosalicylate (5-CSA), 5-flourosalicylate (5-FSA), 4-aminosalicylate (4-ASA), 5-aminosalicylate (5-ASA), 5-nitrosalicylate (5-NSA), and 5-sulfosalicylate (5-SSA), have been synthesized and characterized by various spectroscopic techniques including ultraviolet-visible (UV-vis), infrared (IR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy,13C NMR, and elemental analysis. A detailed study of electrochemistry of all the synthesized compounds has been done to compare their oxidation and reduction mechanisms and to explain the effect of axial coordination on their redox properties.

Zinc porphyrin-anthraquinonylimidazole supramolecular dyads

2020 ◽  
Vol 24 (05n07) ◽  
pp. 850-859
Author(s):  
Federica Sabuzi ◽  
Alessia Coletti ◽  
Valeria Conte ◽  
Barbara Floris ◽  
Pierluca Galloni
Keyword(s):  
Electron Transfer ◽  
Chain Length ◽  
Strong Correlation ◽  
Transient Absorption ◽  
Binding Constants ◽  
Spectroscopic Characterization ◽  
Zinc Ion ◽  
Transient Absorption Spectroscopy ◽  
Zinc Porphyrin

In this work, the synthesis and spectroscopic characterization of new zinc porphyrin-anthraquinone dyads is proposed. In particular, electron donor units based on zinc meso-tetraphenylporphyrin (ZnTPP) and zinc octaethylporphyrin (ZnOEP) have been coupled with differently substituted anthraquinones as acceptors. The quinone moiety was properly functionalized with imidazole, thus ensuring porphyrin complexation through zinc ion coordination. Accordingly, absorption and emission measurements demonstrated that the coordination occurred, and calculated binding constants were in the range 6.6 [Formula: see text] 10[Formula: see text]–3.9 [Formula: see text] 10[Formula: see text] M[Formula: see text]. Transient absorption spectroscopy for ZnTPP and ZnOEP dyads demonstrated that the electron transfer occurred, with the formation of the corresponding charge separated state, ZnTPP[Formula: see text]-AQ. Moreover, in ZnOEP complexes, a strong correlation between the chain length and flexibility with the charge separated state lifetime was observed.

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