The effect of N-methylation on the spectroscopical and electrochemical properties of 1,4,8,11-tetraazacyclotetradecane chromium(III) complexes

Dirk Guldi; F. Wasgestian; Dan Meyerstein

doi:10.1016/S0020-1693(00)85817-X

The effect of N-methylation on the spectroscopical and electrochemical properties of 1,4,8,11-tetraazacyclotetradecane chromium(III) complexes

Dirk Guldi, F. Wasgestian, Dan Meyerstein

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

5 Scopus citations

Abstract

trans-[Cr(tmc)X₂] complexes (tmc=1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, XF, Cl, Br, H₂O, OH, NO₃) have been prepared and spectroscopically characterized. The redox potentials of the tmc complexes and of the analogous cyclam complexes (cyclam=1,4,8,11-tetraazacyclotetradecane) were determined by cyclic voltammetry. The potentials of the tmc complexes are 1.1±0.1 V more positive. Their long wavelength absorption is red-shifted by 50 to 100 nm with respect to that of the analogous cyclam complexes. The shift was consistent with a linear dependence of the polarographic half-wave potentials on the transition energies of the first spin allowed ligand field bands, observed on a series of chromium(III) amine complexes. The reaction entropies for the reduction of trans-[Cr(cyclam)(H₂O)₂]³⁺, trans-[Cr(cyclam)(OH)₂]⁺, and trans-[Cr(tmc)(OH)₂]⁺, ΔS=88±2, 200±40 and 53±8 J mol^-1 K^-1, respectively, were obtained from the temperature dependence of the redox potential. It was shown that trans-[Cr(cyclam)(H₂O)₂]³⁺ catalyzes the electroreduction of nitrate.

Original language	English
Pages (from-to)	15-22
Number of pages	8
Journal	Inorganica Chimica Acta
Volume	194
Issue number	1
DOIs	https://doi.org/10.1016/S0020-1693(00)85817-X
State	Published - 1 Apr 1992

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Inorganic Chemistry
Materials Chemistry

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@article{4a50a6d614da40e69cf06b87f7c73067,

title = "The effect of N-methylation on the spectroscopical and electrochemical properties of 1,4,8,11-tetraazacyclotetradecane chromium(III) complexes",

abstract = "trans-[Cr(tmc)X2] complexes (tmc=1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, XF, Cl, Br, H2O, OH, NO3) have been prepared and spectroscopically characterized. The redox potentials of the tmc complexes and of the analogous cyclam complexes (cyclam=1,4,8,11-tetraazacyclotetradecane) were determined by cyclic voltammetry. The potentials of the tmc complexes are 1.1±0.1 V more positive. Their long wavelength absorption is red-shifted by 50 to 100 nm with respect to that of the analogous cyclam complexes. The shift was consistent with a linear dependence of the polarographic half-wave potentials on the transition energies of the first spin allowed ligand field bands, observed on a series of chromium(III) amine complexes. The reaction entropies for the reduction of trans-[Cr(cyclam)(H2O)2]3+, trans-[Cr(cyclam)(OH)2]+, and trans-[Cr(tmc)(OH)2]+, ΔS=88±2, 200±40 and 53±8 J mol-1 K-1, respectively, were obtained from the temperature dependence of the redox potential. It was shown that trans-[Cr(cyclam)(H2O)2]3+ catalyzes the electroreduction of nitrate.",

author = "Dirk Guldi and F. Wasgestian and Dan Meyerstein",

year = "1992",

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doi = "10.1016/S0020-1693(00)85817-X",

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T1 - The effect of N-methylation on the spectroscopical and electrochemical properties of 1,4,8,11-tetraazacyclotetradecane chromium(III) complexes

AU - Guldi, Dirk

AU - Wasgestian, F.

AU - Meyerstein, Dan

PY - 1992/4/1

Y1 - 1992/4/1

N2 - trans-[Cr(tmc)X2] complexes (tmc=1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, XF, Cl, Br, H2O, OH, NO3) have been prepared and spectroscopically characterized. The redox potentials of the tmc complexes and of the analogous cyclam complexes (cyclam=1,4,8,11-tetraazacyclotetradecane) were determined by cyclic voltammetry. The potentials of the tmc complexes are 1.1±0.1 V more positive. Their long wavelength absorption is red-shifted by 50 to 100 nm with respect to that of the analogous cyclam complexes. The shift was consistent with a linear dependence of the polarographic half-wave potentials on the transition energies of the first spin allowed ligand field bands, observed on a series of chromium(III) amine complexes. The reaction entropies for the reduction of trans-[Cr(cyclam)(H2O)2]3+, trans-[Cr(cyclam)(OH)2]+, and trans-[Cr(tmc)(OH)2]+, ΔS=88±2, 200±40 and 53±8 J mol-1 K-1, respectively, were obtained from the temperature dependence of the redox potential. It was shown that trans-[Cr(cyclam)(H2O)2]3+ catalyzes the electroreduction of nitrate.

AB - trans-[Cr(tmc)X2] complexes (tmc=1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, XF, Cl, Br, H2O, OH, NO3) have been prepared and spectroscopically characterized. The redox potentials of the tmc complexes and of the analogous cyclam complexes (cyclam=1,4,8,11-tetraazacyclotetradecane) were determined by cyclic voltammetry. The potentials of the tmc complexes are 1.1±0.1 V more positive. Their long wavelength absorption is red-shifted by 50 to 100 nm with respect to that of the analogous cyclam complexes. The shift was consistent with a linear dependence of the polarographic half-wave potentials on the transition energies of the first spin allowed ligand field bands, observed on a series of chromium(III) amine complexes. The reaction entropies for the reduction of trans-[Cr(cyclam)(H2O)2]3+, trans-[Cr(cyclam)(OH)2]+, and trans-[Cr(tmc)(OH)2]+, ΔS=88±2, 200±40 and 53±8 J mol-1 K-1, respectively, were obtained from the temperature dependence of the redox potential. It was shown that trans-[Cr(cyclam)(H2O)2]3+ catalyzes the electroreduction of nitrate.

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DO - 10.1016/S0020-1693(00)85817-X

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ER -

The effect of N-methylation on the spectroscopical and electrochemical properties of 1,4,8,11-tetraazacyclotetradecane chromium(III) complexes

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