%0 Journal Article %1 Hartmann.2003 %A Hartmann, Heiko %A Kaim, Wolfgang %A Wanner, Matthias %A Klein, Axel %A Frantz, Stephanie %A Duboc-Toia, Carole %A Fiedler, Jan %A Zalis, Stanislav. %D 2003 %J Inorganic Chemistry %K TCNQ bipyridine carbonyl crystal cyano dinuclear;rhenium electrochem prepn rhenium structure %N 22 %P 7018--7025 %R 10.1021/ic034232l %T Proof of Innocence for the Quintessential Noninnocent Ligand TCNQ in Its Tetranuclear Complex with Four fac-Re(CO)3(bpy)+ Groups: Unusually Different Reactivity of the TCNX Ligands (TCNX = TCNE, TCNQ, TCNB) %V 42 %X The reactions of fac-Re(CO)3(bpy)(MeOH)(PF6), bpy = 2,2'-bipyridine, with the TCNX ligands (TCNE = tetracyanoethene, TCNQ = 7,7,8,8-tetracyano-p-quinodimethane, and TCNB = 1,2,4,5-tetracyanobenzene) in CH2Cl2 gave very different results. No reaction was obsd. with TCNB whereas TCNE produced very labile intermediates which converted under mild conditions to structurally characterized (μ-CN)fac-Re(CO)3(bpy)2(PF6) with an eclipsed conformation relative to the almost linear Re-CN-Re axis (Re-N(NC) 2.134(8) \AA, Re-C(CN) 2.098(8) \AA). With TCNQ, a stable tetranuclear complex (μ4-TCNQ)Re(CO)3(bpy)4(BF4)4 was obtained. Its structural, electrochem., and spectroscopic anal. indicates only negligible charge transfer from the rhenium(I) centers to the extremely strong p acceptor TCNQ. Evidence includes a calcd. charge of only -0.09 for coordinated TCNQ according to the empirical structure/charge correlation of Kistenmacher, a high-energy nitrile stretching band nCN = 2235 cm-1, and unprecedented large anodic shifts \textgreater0.7 V of the redn. potentials. DFT calcns. were used to confirm and explain the absence of electron delocalization from the electron-rich metals to the TCNQ acceptor bridge. Correspondingly, the X-band and high-frequency (285 GHz) EPR data (g = 2.007) as well as the IR and UV-visible-NIR spectroelectrochem. results (marginal nCO shifts, TCNQ.bul.- chromophore bands) support the almost exclusive confinement of the added electron in (μ4-TCNQ)Re(CO)3(bpy)43+ to the TCNQ bridge. on SciFinder(R)

@article{Hartmann.2003, abstract = {The reactions of [fac-Re(CO)3(bpy)(MeOH)](PF6), bpy = 2,2'-bipyridine, with the TCNX ligands (TCNE = tetracyanoethene, TCNQ = 7,7,8,8-tetracyano-p-quinodimethane, and TCNB = 1,2,4,5-tetracyanobenzene) in CH2Cl2 gave very different results. No reaction was obsd. with TCNB whereas TCNE produced very labile intermediates which converted under mild conditions to structurally characterized {(μ-CN)[fac-Re(CO)3(bpy)]2}(PF6) with an eclipsed conformation relative to the almost linear Re-CN-Re axis (Re-N(NC) 2.134(8) {\AA}, Re-C(CN) 2.098(8) {\AA}). With TCNQ, a stable tetranuclear complex {(μ4-TCNQ)[Re(CO)3(bpy)]4}(BF4)4 was obtained. Its structural, electrochem., and spectroscopic anal. indicates only negligible charge transfer from the rhenium(I) centers to the extremely strong \textgreek{p} acceptor TCNQ. Evidence includes a calcd. charge of only -0.09 for coordinated TCNQ according to the empirical structure/charge correlation of Kistenmacher, a high-energy nitrile stretching band \textgreek{n}CN = 2235 cm-1, and unprecedented large anodic shifts {\textgreater}0.7 V of the redn. potentials. DFT calcns. were used to confirm and explain the absence of electron delocalization from the electron-rich metals to the TCNQ acceptor bridge. Correspondingly, the X-band and high-frequency (285 GHz) EPR data (g = 2.007) as well as the IR and UV-visible-NIR spectroelectrochem. results (marginal \textgreek{n}CO shifts, TCNQ.bul.- chromophore bands) support the almost exclusive confinement of the added electron in {(μ4-TCNQ)[Re(CO)3(bpy)]4}3+ to the TCNQ bridge. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Hartmann, Heiko and Kaim, Wolfgang and Wanner, Matthias and Klein, Axel and Frantz, Stephanie and Duboc-Toia, Carole and Fiedler, Jan and Zalis, Stanislav.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2eabfd6dd98ca457f7d16a0b99407b3c0/huebleriac}, doi = {10.1021/ic034232l}, interhash = {33ede6bbed0e224c39646421b67662d2}, intrahash = {eabfd6dd98ca457f7d16a0b99407b3c0}, issn = {0020-1669}, journal = {Inorganic Chemistry}, keywords = {TCNQ bipyridine carbonyl crystal cyano dinuclear;rhenium electrochem prepn rhenium structure}, number = 22, pages = {7018--7025}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Proof of Innocence for the Quintessential Noninnocent Ligand TCNQ in Its Tetranuclear Complex with Four [fac-Re(CO)3(bpy)]+ Groups: Unusually Different Reactivity of the TCNX Ligands (TCNX = TCNE, TCNQ, TCNB)}, volume = 42, year = 2003 }