The mpz+/mpz.bul. pair as organic analog of the NO+/NO.bul. ligand redox system (mpz = N-methylpyrazinium). A combined electrochemical and spectroscopic study (UV/Vis/NIR, IR, EPR) of complexes (mpz)M(CN)52-/3- (M = Fe, Ru, Os)
The oxidn. and redn. behavior of (mpz)M(CN)52- between the group 8 pentacyanometalates(II) and the N-methylpyrazinium ion mpz+ was studied using spectroelectrochem. techniques (UV/visible/NIR, IR, EPR) in nonaq. and, in part, aq. media. As a further source of information on the electronic structure, the authors studied the variable solvatochromism of MLCT absorption bands in the precursor ions (mpz)M(CN)52-. The mpz-centered 1-electron redn. showed a tendency for concomitant loss of cyanide (EC process) to yield (mpz)M(CN)42-, the lability increasing in the order M = Os \textless\textless Ru \textless Fe. In contrast to the EPR spectra obtained from redn. with S2O42- in aq. media, which showed no evidence for close mpz.bul./metal assocn., the intra muros electrolysis expts. in DMSO or acetonitrile yielded the following results: The EPR spectrum that was previously assigned to (mpz)Fe(CN)53- is now ascribed to (mpz)Fe(CN)42-. Whereas the dissociatively inert osmium radical complex (mpz)Os(CN)53- is distinguished by a broad EPR signal with a rather large value giso = 2.0157, the EPR spectrum of (mpz)Ru(CN)43- reveals well-resolved sep. coupling with the 99Ru and 101Ru isotopes in natural abundance. Spectroelectrochem. and reactivity patterns of (mpz)M(CN)52- are reminiscent of results for corresponding nitrosyl complexes (NO)M(CN)52-, which suggests that the mpz+/mpz.bul. ligand redox pair can function as an org. analog of the NO+/NO.bul. redox system. on SciFinder(R)
%0 Journal Article
%1 Waldhoer.1997b
%A Waldhoer, Eberhard
%A Kaim, Wolfgang
%A Olabe, Jose A.
%A Slep, Leonardo D.
%A Fiedler, Jan.
%D 1997
%J Inorganic Chemistry
%K IR analog;near complex complex;EPR complex;IR complex;iron complex;osmium complex;visible cyano electrochem metal methylpyrazinium nitrosyl pentacyano redn spectra spectroscopy;UV spectroscopy;electrochem spectroscopy;methylpyrazinium spectroscopy;ruthenium
%N 14
%P 2969--2974
%R 10.1021/IC961426A
%T The mpz+/mpz.bul. pair as organic analog of the NO+/NO.bul. ligand redox system (mpz = N-methylpyrazinium). A combined electrochemical and spectroscopic study (UV/Vis/NIR, IR, EPR) of complexes (mpz)M(CN)52-/3- (M = Fe, Ru, Os)
%V 36
%X The oxidn. and redn. behavior of (mpz)M(CN)52- between the group 8 pentacyanometalates(II) and the N-methylpyrazinium ion mpz+ was studied using spectroelectrochem. techniques (UV/visible/NIR, IR, EPR) in nonaq. and, in part, aq. media. As a further source of information on the electronic structure, the authors studied the variable solvatochromism of MLCT absorption bands in the precursor ions (mpz)M(CN)52-. The mpz-centered 1-electron redn. showed a tendency for concomitant loss of cyanide (EC process) to yield (mpz)M(CN)42-, the lability increasing in the order M = Os \textless\textless Ru \textless Fe. In contrast to the EPR spectra obtained from redn. with S2O42- in aq. media, which showed no evidence for close mpz.bul./metal assocn., the intra muros electrolysis expts. in DMSO or acetonitrile yielded the following results: The EPR spectrum that was previously assigned to (mpz)Fe(CN)53- is now ascribed to (mpz)Fe(CN)42-. Whereas the dissociatively inert osmium radical complex (mpz)Os(CN)53- is distinguished by a broad EPR signal with a rather large value giso = 2.0157, the EPR spectrum of (mpz)Ru(CN)43- reveals well-resolved sep. coupling with the 99Ru and 101Ru isotopes in natural abundance. Spectroelectrochem. and reactivity patterns of (mpz)M(CN)52- are reminiscent of results for corresponding nitrosyl complexes (NO)M(CN)52-, which suggests that the mpz+/mpz.bul. ligand redox pair can function as an org. analog of the NO+/NO.bul. redox system. on SciFinder(R)
@article{Waldhoer.1997b,
abstract = {The oxidn. and redn. behavior of [(mpz)M(CN)5]2- between the group 8 pentacyanometalates(II) and the N-methylpyrazinium ion mpz+ was studied using spectroelectrochem. techniques (UV/visible/NIR, IR, EPR) in nonaq. and, in part, aq. media. As a further source of information on the electronic structure, the authors studied the variable solvatochromism of MLCT absorption bands in the precursor ions [(mpz)M(CN)5]2-. The mpz-centered 1-electron redn. showed a tendency for concomitant loss of cyanide (EC process) to yield [(mpz)M(CN)4]2-, the lability increasing in the order M = Os {\textless}{\textless} Ru {\textless} Fe. In contrast to the EPR spectra obtained from redn. with S2O42- in aq. media, which showed no evidence for close mpz.bul./metal assocn., the intra muros electrolysis expts. in DMSO or acetonitrile yielded the following results: The EPR spectrum that was previously assigned to [(mpz)Fe(CN)5]3- is now ascribed to [(mpz)Fe(CN)4]2-. Whereas the dissociatively inert osmium radical complex [(mpz)Os(CN)5]3- is distinguished by a broad EPR signal with a rather large value giso = 2.0157, the EPR spectrum of [(mpz)Ru(CN)4]3- reveals well-resolved sep. coupling with the 99Ru and 101Ru isotopes in natural abundance. Spectroelectrochem. and reactivity patterns of [(mpz)M(CN)5]2- are reminiscent of results for corresponding nitrosyl complexes [(NO)M(CN)5]2-, which suggests that the mpz+/mpz.bul. ligand redox pair can function as an org. analog of the NO+/NO.bul. redox system. [on SciFinder(R)]},
added-at = {2019-07-15T13:41:23.000+0000},
author = {Waldhoer, Eberhard and Kaim, Wolfgang and Olabe, Jose A. and Slep, Leonardo D. and Fiedler, Jan.},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2a83ace2d15ec7d1724d2428b9ea180ba/b_schwederski},
doi = {10.1021/IC961426A},
interhash = {f80277317110f749ff6a1ec2a77933fb},
intrahash = {a83ace2d15ec7d1724d2428b9ea180ba},
issn = {0020-1669},
journal = {Inorganic Chemistry},
keywords = {IR analog;near complex complex;EPR complex;IR complex;iron complex;osmium complex;visible cyano electrochem metal methylpyrazinium nitrosyl pentacyano redn spectra spectroscopy;UV spectroscopy;electrochem spectroscopy;methylpyrazinium spectroscopy;ruthenium},
number = 14,
pages = {2969--2974},
timestamp = {2019-07-15T11:42:10.000+0000},
title = {The mpz+/mpz.bul. pair as organic analog of the NO+/NO.bul. ligand redox system (mpz = N-methylpyrazinium). A combined electrochemical and spectroscopic study (UV/Vis/NIR, IR, EPR) of complexes [(mpz)M(CN)5]2-/3- (M = Fe, Ru, Os)},
volume = 36,
year = 1997
}