scholarly journals Magnetic, catalytic, EPR and electrochemical studies on binuclear copper(II) complexes derived from 3,4-disubstituted phenol

2003 ◽  
Vol 115 (1) ◽  
pp. 1-14 ◽  
Author(s):  
R. Kannappan ◽  
R. Mahalakshmy ◽  
T. M. Rajendiran ◽  
R. Venkatesan ◽  
P. Sambasiva Rao
Keyword(s):  
Electrochemical Studies ◽  
Binuclear Copper

Structural, EPR, and Electrochemical Studies of Binuclear Copper(II) Complexes of Bis(pentadentate) Ligands Derived from Bis(1,4,7-triazacyclonane) Macrocycles

1998 ◽  
Vol 37 (15) ◽  
pp. 3705-3713 ◽  
Author(s):  
Suzanne J. Brudenell ◽  
Leone Spiccia ◽  
Alan M. Bond ◽  
Peter Comba ◽  
David C. R. Hockless
Keyword(s):  
Electrochemical Studies ◽  
Binuclear Copper ◽  
Pentadentate Ligands

Synthesis, Structural, Magnetic and Electrochemical Studies of Antiferromagnetically Coupled Symmetric Oxamidate-Bridged Binuclear Copper(II) Complexes

2004 ◽  
Vol 2004 (4) ◽  
pp. 872-878 ◽  
Author(s):  
Duraisamy Saravanakumar ◽  
Nallathambi Sengottuvelan ◽  
Vengidusamy Narayanan ◽  
Muthusamy Kandaswamy ◽  
Kandaswamy Chinnakali ◽  
...  
Keyword(s):  
Electrochemical Studies ◽  
Binuclear Copper

Macrocyclic Unsymmetrical Binuclear Copper(II) Complexes as Ligands: Spectral, Structural, Magnetic and Electrochemical Studies

2004 ◽  
Vol 16 (2) ◽  
pp. 129-136 ◽  
Author(s):  
N. Sengottuvelan ◽  
D. Saravanakumar ◽  
S. Sridevi ◽  
V. Narayanan ◽  
M. Kandaswamy
Keyword(s):  
Electrochemical Studies ◽  
Binuclear Copper

Electrochemical studies of binuclear copper(II) complexes

1983 ◽  
Vol 75 ◽  
pp. 155-157 ◽  
Author(s):  
Hideo Doine ◽  
Frank F. Stephens ◽  
Roderick D. Cannon
Keyword(s):  
Electrochemical Studies ◽  
Binuclear Copper

A Pyridinic Fe-N4 Macrocycle Effectively Models the Active Sites in Fe/N-Doped Carbon Electrocatalysts

2020 ◽  
Author(s):  
Travis Marshall-Roth ◽  
Nicole J. Libretto ◽  
Alexandra T. Wrobel ◽  
Kevin Anderton ◽  
Nathan D. Ricke ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Active Sites ◽  
Catalytic Properties ◽  
Reduction Reaction ◽  
Iron Phthalocyanine ◽  
Electrochemical Studies ◽  
Onset Potential ◽  
Nitrogen Doped Carbon ◽  
Iron Active Sites

Iron- and nitrogen-doped carbon (Fe-N-C) materials are leading candidates to replace platinum in fuel cells, but their active site structures are poorly understood. A leading postulate is that iron active sites in this class of materials exist in an Fe-N<sub>4</sub> pyridinic ligation environment. Yet, molecular Fe-based catalysts for the oxygen reduction reaction (ORR) generally feature pyrrolic coordination and pyridinic Fe-N<sub>4</sub> catalysts are, to the best of our knowledge, non-existent. We report the synthesis and characterization of a molecular pyridinic hexaazacyclophane macrocycle, (phen<sub>2</sub>N<sub>2</sub>)Fe, and compare its spectroscopic, electrochemical, and catalytic properties for oxygen reduction to a prototypical Fe-N-C material, as well as iron phthalocyanine, (Pc)Fe, and iron octaethylporphyrin, (OEP)Fe, prototypical pyrrolic iron macrocycles. N 1s XPS signatures for coordinated N atoms in (phen<sub>2</sub>N<sub>2</sub>)Fe are positively shifted relative to (Pc)Fe and (OEP)Fe, and overlay with those of Fe-N-C. Likewise, spectroscopic XAS signatures of (phen<sub>2</sub>N<sub>2</sub>)Fe are distinct from those of both (Pc)Fe and (OEP)Fe, and are remarkably similar to those of Fe-N-C with compressed Fe–N bond lengths of 1.97 Å in (phen<sub>2</sub>N<sub>2</sub>)Fe that are close to the average 1.94 Å length in Fe-N-C. Electrochemical studies establish that both (Pc)Fe and (phen<sub>2</sub>N<sub>2</sub>)Fe have relatively high Fe(III/II) potentials at ~0.6 V, ~300 mV positive of (OEP)Fe. The ORR onset potential is found to directly correlate with the Fe(III/II) potential leading to a ~300 mV positive shift in the onset of ORR for (Pc)Fe and (phen<sub>2</sub>N<sub>2</sub>)Fe relative to (OEP)Fe. Consequently, the ORR onset for (phen<sub>2</sub>N<sub>2</sub>)Fe and (Pc)Fe is within 150 mV of Fe-N-C. Unlike (OEP)Fe and (Pc)Fe, (phen<sub>2</sub>N<sub>2</sub>)Fe displays excellent selectivity for 4-electron ORR with <4% maximum H<sub>2</sub>O<sub>2</sub> production, comparable to Fe-N-C materials. The aggregate spectroscopic and electrochemical data establish (phen<sub>2</sub>N<sub>2</sub>)Fe as a pyridinic iron macrocycle that effectively models Fe-N-C active sites, thereby providing a rich molecular platform for understanding this important class of catalytic materials.<p><b></b></p>

Sign in / Sign up

Export Citation Format

Share Document