- Electrochemical CO2 Reduction-The Effect of Chalcogenide Exchange in Ni-Isocyclam Complexes
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Among the numerous homogeneous electrochemical CO2 reduction catalysts, [Ni(cyclam)]2+ is known as one of the most potent catalysts. Likewise, [Ni(isocyclam)]2+ was reported to enable electrochemical CO2 conversion but has received significantly less attention. However, for both catalysts, a purposeful substitution of a single nitrogen donor group by chalcogen atoms was never reported. In this work, we report a series of isocyclam-based Ni complexes with {ON3}, {SN3}, {SeN3}, and {N4} moieties and investigated the influence of nitrogen/chalcogen substitution on electrochemical CO2 reduction. While [Ni(isocyclam)]2+ showed the highest selectivity toward CO2 reduction within this series with a Faradaic efficiency of 86% for the generation of CO at an overpotential of-1.20 V and acts as a homogeneous catalyst, the O-and S-containing Ni complexes revealed comparable catalytic activities at ca. 0.3 V milder overpotential but tend to form deposits on the electrode, acting as precursors for a heterogeneous catalysis. Moreover, the heterogeneous species generated from the O-and S-containing complexes enable a catalytic hydride transfer to acetonitrile, resulting in the generation of acetaldehyde. The incorporation of selenium, however, resulted in loss of CO2 reduction activity, mainly leading to hydrogen generation that is also catalyzed by a heterogeneous electrodeposit.
- Apfel, Ulf-Peter,Battistella, Beatrice,Gerschel, Philipp,Ray, Kallol,Siegmund, Daniel
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p. 1497 - 1510
(2020/04/30)
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- A Highly Reactive Oxoiron(IV) Complex Supported by a Bioinspired N3O Macrocyclic Ligand
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The sluggish oxidants [FeIV(O)(TMC)(CH3CN)]2+ (TMC=1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) and [FeIV(O)(TMCN-d12)(OTf)]+ (TMCN-d12=1,4,7,11-tetra(methyl-d3/
- Monte Pérez, Inés,Engelmann, Xenia,Lee, Yong-Min,Yoo, Mi,Kumaran, Elumalai,Farquhar, Erik R.,Bill, Eckhard,England, Jason,Nam, Wonwoo,Swart, Marcel,Ray, Kallol
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p. 14384 - 14388
(2017/10/23)
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- A convenient synthesis of isocyclam and [16]aneN4 and the photophysics of their dicyanochromium(III) complexes
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The syntheses of the tetraazamacrocyclic ligands 1,4,7,11-tetraazacyclotetradecane (isocyclam) and 1,5,9,13-tetraazacyclohexadecane ([16]aneN4) in two steps starting from the corresponding tetraamine and diethylmalonate is reported. The trans-dicyanochromium(III) complexes, trans-[Cr(isocyclam)(CN)2]PF6 and trans-[Cr([16]aneN4)(CN)2]PF6 have also been prepared. Both are 2Eg emitters with 0-0 band emission wavelengths at 721.2 and 704.8 nm, respectively. The isocyclam complex has a room temperature excited state lifetime of 147 μs in aqueous solution which increases to 215 μs upon macrocyclic N-H deuteration, whereas the corresponding lifetime of the [16]aneN4 complex is 25 μs and is unaffected by macrocyclic N-H deuteration. The implications of the temperature dependence of the excited state lifetimes are also presented.
- Grisenti, David L.,Smith, Mary beth,Fang, Luxi,Bishop, Nicholas,Wagenknecht, Paul S.
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experimental part
p. 157 - 162
(2010/06/12)
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- Metal Complexes with Macrocyclic Ligands, XVII. Synthesis of Two Key Intermediates for the Preparation of Mono-N-functionalized Tetraazamacrocycles and Their Metal Complexes
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With a modification of the cyclization procedure of Richman and Atkins the two macrocycles 1,4,7-tritosyl-11-benzyl-1,4,7,11-tetraazacyclotetradecane (8) and 1,7,11-tritosyl-4-trityl-1,4,7,11-tetraazacyclotetradecane (15) were prepared.After selective
- Hediger, Markus,Kaden, Thomas A.
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p. 861 - 870
(2007/10/02)
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