Multistep redox sequences of azopyridyl (L) bridged reaction centers in stable radical complex ions (μ-L)MCl(η5-C5Me5)2$\surd$+, M = Rh or Ir: Spectroelectrochemistry and high-frequency EPR spectroscopy
The dinuclear complex cations (μ-L)MCl(η5-C5Me5)2n, M = Rh or Ir and L = abpy (= 2,2'-azobispyridine) or abcp (= 2,2'-azobis(5-chloropyrimidine)), could be isolated as paramagnetic hexafluorophosphates (n = 1+) or, for M = Ir, as diamagnetic bis-hexafluorophosphates (n = 2+). In addn. to the reversible one-electron process as indicated by this convertibility there are two successive chloride-releasing redn. steps, sepd. by unusually large potential differences DEEC between 0.75 V (Rh2/abpy) and 1.14 V (Ir2/abcp), leading to the spectroelectrochem. characterized complexes (η5-Me5C5)M(μ-L)MCl(η5-C5Me5)+ and (m-L)M(h5-C5Me5)2. This large splitting of DEEC establishes the capability of azopyridyl bridges for mediating efficient metal-metal communication beyond mere electron transfer. The neutral complexes (m-L)M(h5-C5Me5)2 are distinguished by a series of intense absorption bands in the near IR, the lowest absorption energies being displayed by the Ir2/abcp combination. The stable electron reservoir intermediates (μ-L)MCl(η5-C5Me5)2+ were identified as complexes of L.- anion radicals via their small g anisotropy as measured through high-frequency (\textgreater200 GHz) EPR spectroscopy. on SciFinder(R)
%0 Journal Article
%1 Frantz.2003
%A Frantz, Stephanie
%A Reinhardt, Ralf
%A Greulich, Stefan
%A Wanner, Matthias
%A Fiedler, Jan
%A Duboc-Toia, Carole
%A Kaim, Wolfgang.
%D 2003
%J Dalton Transactions
%K ESR azopyridyl azopyrimidine azopyrimidinyl bridged bridged;spectro cation cyclopentadienyl electrochem ion iridium pentamethylcyclopentadienyl prepn;radical radical rhodium
%N 17
%P 3370--3375
%R 10.1039/B305311C
%T Multistep redox sequences of azopyridyl (L) bridged reaction centers in stable radical complex ions (μ-L)MCl(η5-C5Me5)2$\surd$+, M = Rh or Ir: Spectroelectrochemistry and high-frequency EPR spectroscopy
%X The dinuclear complex cations (μ-L)MCl(η5-C5Me5)2n, M = Rh or Ir and L = abpy (= 2,2'-azobispyridine) or abcp (= 2,2'-azobis(5-chloropyrimidine)), could be isolated as paramagnetic hexafluorophosphates (n = 1+) or, for M = Ir, as diamagnetic bis-hexafluorophosphates (n = 2+). In addn. to the reversible one-electron process as indicated by this convertibility there are two successive chloride-releasing redn. steps, sepd. by unusually large potential differences DEEC between 0.75 V (Rh2/abpy) and 1.14 V (Ir2/abcp), leading to the spectroelectrochem. characterized complexes (η5-Me5C5)M(μ-L)MCl(η5-C5Me5)+ and (m-L)M(h5-C5Me5)2. This large splitting of DEEC establishes the capability of azopyridyl bridges for mediating efficient metal-metal communication beyond mere electron transfer. The neutral complexes (m-L)M(h5-C5Me5)2 are distinguished by a series of intense absorption bands in the near IR, the lowest absorption energies being displayed by the Ir2/abcp combination. The stable electron reservoir intermediates (μ-L)MCl(η5-C5Me5)2+ were identified as complexes of L.- anion radicals via their small g anisotropy as measured through high-frequency (\textgreater200 GHz) EPR spectroscopy. on SciFinder(R)
@article{Frantz.2003,
abstract = {The dinuclear complex cations {(μ-L)[MCl(η5-C5Me5)]2}n, M = Rh or Ir and L = abpy (= 2,2'-azobispyridine) or abcp (= 2,2'-azobis(5-chloropyrimidine)), could be isolated as paramagnetic hexafluorophosphates (n = 1+) or, for M = Ir, as diamagnetic bis-hexafluorophosphates (n = 2+). In addn. to the reversible one-electron process as indicated by this convertibility there are two successive chloride-releasing redn. steps, sepd. by unusually large potential differences \textgreek{D}EEC between 0.75 V (Rh2/abpy) and 1.14 V (Ir2/abcp), leading to the spectroelectrochem. characterized complexes {[(η5-Me5C5)M](μ-L)[MCl(η5-C5Me5)]}+ and (\textgreek{m}-L)[M(\textgreek{h}5-C5Me5)]2. This large splitting of \textgreek{D}EEC establishes the capability of azopyridyl bridges for mediating efficient metal-metal communication beyond mere electron transfer. The neutral complexes (\textgreek{m}-L)[M(\textgreek{h}5-C5Me5)]2 are distinguished by a series of intense absorption bands in the near IR, the lowest absorption energies being displayed by the Ir2/abcp combination. The stable electron reservoir intermediates {(μ-L)[MCl(η5-C5Me5)]2}+ were identified as complexes of L.- anion radicals via their small g anisotropy as measured through high-frequency ({\textgreater}200 GHz) EPR spectroscopy. [on SciFinder(R)]},
added-at = {2022-06-15T11:26:56.000+0200},
author = {Frantz, Stephanie and Reinhardt, Ralf and Greulich, Stefan and Wanner, Matthias and Fiedler, Jan and Duboc-Toia, Carole and Kaim, Wolfgang.},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/22de3933d5230a5b44bd0410870c4d428/huebleriac},
doi = {10.1039/B305311C},
interhash = {57df72f98cf9262069d76c05bd5978e0},
intrahash = {2de3933d5230a5b44bd0410870c4d428},
issn = {1477-9226},
journal = {Dalton Transactions},
keywords = {ESR azopyridyl azopyrimidine azopyrimidinyl bridged bridged;spectro cation cyclopentadienyl electrochem ion iridium pentamethylcyclopentadienyl prepn;radical radical rhodium},
number = 17,
pages = {3370--3375},
timestamp = {2022-06-15T09:26:56.000+0200},
title = {Multistep redox sequences of azopyridyl (L) bridged reaction centers in stable radical complex ions {(μ-L)[MCl(η5-C5Me5)]2}$\surd$+, M = Rh or Ir: Spectroelectrochemistry and high-frequency EPR spectroscopy},
year = 2003
}
