%0 Journal Article %1 Baumann.1997b %A Baumann, Frank %A Kaim, Wolfgang %A Olabe, Jose A. %A Parise, Alejandro R. %A Jordanov, Jeanne. %D 1997 %J Journal of the Chemical Society, Dalton Transactions: Inorganic Chemistry %K TCNB TCNQ charge complex complex;osmium intervalence magnetism magnetism;TCNQ osmium prepn spectroelectrochem spectroelectrochem;TCNB tetranuclear tetranuclear;magnetism transfer %N 22 %P 4455--4460 %T Tetranuclear osmium complexes of tetracyanoquinodimethane TCNQ, 2,2'-(cyclohexa-2,5-diene-1,4-diylidene)bis(propane-1,3-dinitrile) and 1,2,4,5-tetracyanobenzene (TCNB). Synthesis, spectroelectrochemistry and magnetism %X Tetranuclear complexes (m4,h4-TCNX)Os(PPri3)2(CO)(H)Cl4 TCNX = tetracyanoquinodimethane (TCNQ, 2,2'-(cyclohexa-2,5-diene-1,4-diylidene)bis(propane-1,3-dinitrile)) or 1,2,4,5-tetracyanobenzene (TCNB), were prepd. and studied by spectroelectrochem. in the UV/visible/NIR and IR regions and by EPR spectroscopy. Both compds. are reduced in two reversible steps and oxidized in a two-electron process (reversible for TCNQ, quasi-reversible for TCNB). In all oxidn. states studied (-, 0, 2+) the TCNQ complexes exhibited intense long-wavelength absorptions in the near IR region (lmax \textgreater 1000 nm). The EPR spectra of the monoanionic forms exhibit hardly any g anisotropy and thus very little metal participation, suggesting an oxidn. state formulation (TCNX.bul.-)(OsII)4. The dication of the TCNQ system is formulated as (TCNQ)(Os2.5)4 with an intervalence transfer transition at lmax = 1245 nm (e = 50,000 M-1 cm-1). In the solid state, the neutral complexes show temp. dependent paramagnetism that could be fitted with a model implying two coupled S = 1/2 entities. on SciFinder(R)

@article{Baumann.1997b, abstract = {Tetranuclear complexes [(\textgreek{m}4,\textgreek{h}4-TCNX){Os(PPri3)2(CO)(H)Cl}4] [TCNX = tetracyanoquinodimethane (TCNQ, 2,2'-(cyclohexa-2,5-diene-1,4-diylidene)bis(propane-1,3-dinitrile)) or 1,2,4,5-tetracyanobenzene (TCNB)], were prepd. and studied by spectroelectrochem. in the UV/visible/NIR and IR regions and by EPR spectroscopy. Both compds. are reduced in two reversible steps and oxidized in a two-electron process (reversible for TCNQ, quasi-reversible for TCNB). In all oxidn. states studied (-, 0, 2+) the TCNQ complexes exhibited intense long-wavelength absorptions in the near IR region (\textgreek{l}max {\textgreater} 1000 nm). The EPR spectra of the monoanionic forms exhibit hardly any g anisotropy and thus very little metal participation, suggesting an oxidn. state formulation [(TCNX.bul.-)(OsII)4]. The dication of the TCNQ system is formulated as [(TCNQ)(Os2.5)4] with an intervalence transfer transition at \textgreek{l}max = 1245 nm (\textgreek{e} = 50,000 M-1 cm-1). In the solid state, the neutral complexes show temp. dependent paramagnetism that could be fitted with a model implying two coupled S = 1/2 entities. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Baumann, Frank and Kaim, Wolfgang and Olabe, Jose A. and Parise, Alejandro R. and Jordanov, Jeanne.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/203c4583bbe6b6c36549b8ca4dbe985f6/huebleriac}, interhash = {c4aec7ae7bc1f016da9bf78c9e2c7e1c}, intrahash = {03c4583bbe6b6c36549b8ca4dbe985f6}, issn = {0300-9246}, journal = {Journal of the Chemical Society, Dalton Transactions: Inorganic Chemistry}, keywords = {TCNB TCNQ charge complex complex;osmium intervalence magnetism magnetism;TCNQ osmium prepn spectroelectrochem spectroelectrochem;TCNB tetranuclear tetranuclear;magnetism transfer}, number = 22, pages = {4455--4460}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Tetranuclear osmium complexes of tetracyanoquinodimethane [TCNQ, 2,2'-(cyclohexa-2,5-diene-1,4-diylidene)bis(propane-1,3-dinitrile)] and 1,2,4,5-tetracyanobenzene (TCNB). Synthesis, spectroelectrochemistry and magnetism}, year = 1997 }