Electron Paramagnetic Resonance and Spectroscopic Characteristics of Electrogenerated Mixed-Valent Systems (h5-C5Me5)M(m-L)M(h5-C5Me5)+ (M = Rh, Ir; L = 2,5-Diiminopyrazines) in Relation to the Radicals (h5-C5Me5)ClM(m-L)MCl(h5-C5Me5)+ and (h5-C5Me5)M(m-L)MCl(h5-C5Me5)2+
Electrochem. redn. of the dinuclear (h5-C5Me5)ClM(m-L)MCl(h5-C5Me5)2+ ions (M = Rh, Ir; L = 2,5-bis(1-phenyliminoethyl)pyrazine (bpip) and 2,5-bis1-(2,6-dimethylphenyl)iminoethylpyrazine (bxip)) proceeds via the paramagnetic intermediates (h5-C5Me5)ClM(m-L)MCl(h5-C5Me5)+ (L = bpip) or (h5-C5Me5)M(m-L)MCl(h5-C5Me5)2+ (L = bxip) and (h5-C5Me5)M(m-L)M(h5-C5Me5)+. Whereas the first is clearly a radical species with a small g anisotropy, the chloride-free cations are distinguished by structured intervalence charge transfer (IVCT) bands in the near-IR region and by rhombic ESR features between g = 1.9 and g = 2.3, which suggests considerable metal participation at the singly occupied MO. Alternatives for the d configuration assignment and for the role of the bisbidentate-conjugated bridging ligands will be discussed. The main difference between bpip and bxip systems is the destabilization of the chloride-contg. forms through the bxip ligand for reasons of steric interference. on SciFinder(R)
%0 Journal Article
%1 Berger.2000
%A Berger, Sascha
%A Klein, Axel
%A Wanner, Matthias
%A Kaim, Wolfgang
%A Fiedler, Jan.
%D 2000
%J Inorganic Chemistry
%K bpip bxip chloro cyclopentadienyl diiminopyrazine electrochem iridium mixed pentamethylcyclopentadienyl pentamethylcyclopentadienyl;iminoethyl prepn pyrazine redn redn;ESR rhodium valent
%N 12
%P 2516--2521
%R 10.1021/ic991110d
%T Electron Paramagnetic Resonance and Spectroscopic Characteristics of Electrogenerated Mixed-Valent Systems (h5-C5Me5)M(m-L)M(h5-C5Me5)+ (M = Rh, Ir; L = 2,5-Diiminopyrazines) in Relation to the Radicals (h5-C5Me5)ClM(m-L)MCl(h5-C5Me5)+ and (h5-C5Me5)M(m-L)MCl(h5-C5Me5)2+
%V 39
%X Electrochem. redn. of the dinuclear (h5-C5Me5)ClM(m-L)MCl(h5-C5Me5)2+ ions (M = Rh, Ir; L = 2,5-bis(1-phenyliminoethyl)pyrazine (bpip) and 2,5-bis1-(2,6-dimethylphenyl)iminoethylpyrazine (bxip)) proceeds via the paramagnetic intermediates (h5-C5Me5)ClM(m-L)MCl(h5-C5Me5)+ (L = bpip) or (h5-C5Me5)M(m-L)MCl(h5-C5Me5)2+ (L = bxip) and (h5-C5Me5)M(m-L)M(h5-C5Me5)+. Whereas the first is clearly a radical species with a small g anisotropy, the chloride-free cations are distinguished by structured intervalence charge transfer (IVCT) bands in the near-IR region and by rhombic ESR features between g = 1.9 and g = 2.3, which suggests considerable metal participation at the singly occupied MO. Alternatives for the d configuration assignment and for the role of the bisbidentate-conjugated bridging ligands will be discussed. The main difference between bpip and bxip systems is the destabilization of the chloride-contg. forms through the bxip ligand for reasons of steric interference. on SciFinder(R)
@article{Berger.2000,
abstract = {Electrochem. redn. of the dinuclear [(\textgreek{h}5-C5Me5)ClM(\textgreek{m}-L)MCl(\textgreek{h}5-C5Me5)]2+ ions (M = Rh, Ir; L = 2,5-bis(1-phenyliminoethyl)pyrazine (bpip) and 2,5-bis[1-(2,6-dimethylphenyl)iminoethyl]pyrazine (bxip)) proceeds via the paramagnetic intermediates [(\textgreek{h}5-C5Me5)ClM(\textgreek{m}-L)MCl(\textgreek{h}5-C5Me5)]+ (L = bpip) or [(\textgreek{h}5-C5Me5)M(\textgreek{m}-L)MCl(\textgreek{h}5-C5Me5)]2+ (L = bxip) and [(\textgreek{h}5-C5Me5)M(\textgreek{m}-L)M(\textgreek{h}5-C5Me5)]+. Whereas the first is clearly a radical species with a small g anisotropy, the chloride-free cations are distinguished by structured intervalence charge transfer (IVCT) bands in the near-IR region and by rhombic ESR features between g = 1.9 and g = 2.3, which suggests considerable metal participation at the singly occupied MO. Alternatives for the d configuration assignment and for the role of the bisbidentate-conjugated bridging ligands will be discussed. The main difference between bpip and bxip systems is the destabilization of the chloride-contg. forms through the bxip ligand for reasons of steric interference. [on SciFinder(R)]},
added-at = {2022-06-15T11:26:56.000+0200},
author = {Berger, Sascha and Klein, Axel and Wanner, Matthias and Kaim, Wolfgang and Fiedler, Jan.},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/27754a47c08ab2109f07ba651abf8dce0/huebleriac},
doi = {10.1021/ic991110d},
interhash = {f87d5dc8a0c2e38dc20c77403983404c},
intrahash = {7754a47c08ab2109f07ba651abf8dce0},
issn = {0020-1669},
journal = {Inorganic Chemistry},
keywords = {bpip bxip chloro cyclopentadienyl diiminopyrazine electrochem iridium mixed pentamethylcyclopentadienyl pentamethylcyclopentadienyl;iminoethyl prepn pyrazine redn redn;ESR rhodium valent},
number = 12,
pages = {2516--2521},
timestamp = {2022-06-15T09:26:56.000+0200},
title = {Electron Paramagnetic Resonance and Spectroscopic Characteristics of Electrogenerated Mixed-Valent Systems [(\textgreek{h}5-C5Me5)M(\textgreek{m}-L)M(\textgreek{h}5-C5Me5)]+ (M = Rh, Ir; L = 2,5-Diiminopyrazines) in Relation to the Radicals [(\textgreek{h}5-C5Me5)ClM(\textgreek{m}-L)MCl(\textgreek{h}5-C5Me5)]+ and [(\textgreek{h}5-C5Me5)M(\textgreek{m}-L)MCl(\textgreek{h}5-C5Me5)]2+},
volume = 39,
year = 2000
}