The reaction of pyrazine or 4,4'-bipyridine radical monoanions with M(CO)6 (M = Mo, W) yielded the stable radical anions of pentacarbonyl complexes which could be identified and analyzed by high-resoln. ESR. When compared with the free ligand anion radicals the paramagnetic complexes show distinct differences: (1) the proton coupling aH is slightly reduced upon complexation, indicating a flow of spin d. to the N centers and, possibly, to the metal carbonyl fragments; and (2) the N consts. aN of the complexes have increased significantly relative to the free anion radicals and metal isotope coupling reveals non-zero spin population at the metal center. The 13C satellite lines suggest a configurationally stable structure with 6-coordinate metal atoms and 2 sets of 8 equatorial and 2 axial carbonyl groups. The stabilized radical anion grouped state of these systems is described by hyperconjugative interaction of the ligand LUMO (p*) with antibonding metal-carbonyl s* orbitals. on SciFinder(R)
%0 Journal Article
%1 Kaim.1981k
%A Kaim, Wolfgang.
%D 1981
%J Inorganica Chimica Acta
%K ESR ESR;ESR ESR;carbonyl ESR;tungsten anion anion;molybdenum bipyridine metal pyrazine radical
%N 4
%P L151-L153
%R 10.1016/S0020-1693(00)84778-7
%T The reaction of heterocyclic anion radicals with Group VI carbonyls. ESR characterization of paramagnetic binuclear complexes
%V 53
%X The reaction of pyrazine or 4,4'-bipyridine radical monoanions with M(CO)6 (M = Mo, W) yielded the stable radical anions of pentacarbonyl complexes which could be identified and analyzed by high-resoln. ESR. When compared with the free ligand anion radicals the paramagnetic complexes show distinct differences: (1) the proton coupling aH is slightly reduced upon complexation, indicating a flow of spin d. to the N centers and, possibly, to the metal carbonyl fragments; and (2) the N consts. aN of the complexes have increased significantly relative to the free anion radicals and metal isotope coupling reveals non-zero spin population at the metal center. The 13C satellite lines suggest a configurationally stable structure with 6-coordinate metal atoms and 2 sets of 8 equatorial and 2 axial carbonyl groups. The stabilized radical anion grouped state of these systems is described by hyperconjugative interaction of the ligand LUMO (p*) with antibonding metal-carbonyl s* orbitals. on SciFinder(R)
@article{Kaim.1981k,
abstract = {The reaction of pyrazine or 4,4'-bipyridine radical monoanions with M(CO)6 (M = Mo, W) yielded the stable radical anions of pentacarbonyl complexes which could be identified and analyzed by high-resoln. ESR. When compared with the free ligand anion radicals the paramagnetic complexes show distinct differences: (1) the proton coupling aH is slightly reduced upon complexation, indicating a flow of spin d. to the N centers and, possibly, to the metal carbonyl fragments; and (2) the N consts. aN of the complexes have increased significantly relative to the free anion radicals and metal isotope coupling reveals non-zero spin population at the metal center. The 13C satellite lines suggest a configurationally stable structure with 6-coordinate metal atoms and 2 sets of 8 equatorial and 2 axial carbonyl groups. The stabilized radical anion grouped state of these systems is described by hyperconjugative interaction of the ligand LUMO (\textgreek{p}*) with antibonding metal-carbonyl \textgreek{s}* orbitals. [on SciFinder(R)]},
added-at = {2022-06-15T11:26:56.000+0200},
author = {Kaim, Wolfgang.},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/20140ac529ef7d602c035a35641425b39/huebleriac},
doi = {10.1016/S0020-1693(00)84778-7},
interhash = {5d33f5c7a010e7f72c5c680bbbee0018},
intrahash = {0140ac529ef7d602c035a35641425b39},
issn = {0020-1693},
journal = {Inorganica Chimica Acta},
keywords = {ESR ESR;ESR ESR;carbonyl ESR;tungsten anion anion;molybdenum bipyridine metal pyrazine radical},
number = 4,
pages = {L151-L153},
timestamp = {2022-06-15T09:26:56.000+0200},
title = {The reaction of heterocyclic anion radicals with Group VI carbonyls. ESR characterization of paramagnetic binuclear complexes},
volume = 53,
year = 1981
}
