%0 Journal Article %1 Gloeckle.1999 %A Gloeckle, Markus %A Kaim, Wolfgang %A Katz, Nestor E. %A Posse, Monica Garcia %A Cutin, Edgardo H. %A Fiedler, Jan. %D 1999 %J Inorganic Chemistry %K bipyrimidine complex complex;iron complex;redn complex;redox complex;spectroelectrochem cyano dinuclear electrochem iron potential prepn;oxidn spectro tetrazinebispyridine %N 14 %P 3270--3274 %R 10.1021/IC990249L %T The FeIII/FeII vs. Fe22.5 Formulation in Mixed-Valent Species [(NC)4Fe(BL)Fe(CN)4]3-, BL = 2,2'-Bipyrimidine and 3,6-Bis(2-pyridyl)-1,2,4,5-tetrazine. Distance and Size Do Not Always Matter %V 38 %X Two mol.-bridged bis(tetracyanoiron) complexes [(NC)4Fe(BL)Fe(CN)4]n-, BL = 2,2'-bipyrimidine (bpym) and 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz), were studied by EPR, UV/visible/near-IR and IR spectroelectrochem. (n = 2-5) in aprotic media. Following these results, the Fe22.5 formulation is the correct valence description for the metal centers in the bptz-bridged trianion (Kc = 1014.6 in MeCN), whereas the localized FeIII/FeII formulation is appropriate for the bpym-bridged system (Kc = 105.4 in MeCN and 106.4 in CH2Cl2). In contrast to common perception, the larger tetrazine-bridged system with the longer metal-metal distance exhibits much stronger metal-metal coupling than the bpym-bridged analog, a consequence of the very low lying p* LUMO of tetrazines with high MO coeffs. at the coordinating N centers. [on SciFinder(R)]

@article{Gloeckle.1999, abstract = {Two mol.-bridged bis(tetracyanoiron) complexes [(NC)4Fe(BL)Fe(CN)4]n-, BL = 2,2'-bipyrimidine (bpym) and 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz), were studied by EPR, UV/visible/near-IR and IR spectroelectrochem. (n = 2-5) in aprotic media. Following these results, the Fe22.5 formulation is the correct valence description for the metal centers in the bptz-bridged trianion (Kc = 1014.6 in MeCN), whereas the localized FeIII/FeII formulation is appropriate for the bpym-bridged system (Kc = 105.4 in MeCN and 106.4 in CH2Cl2). In contrast to common perception, the larger tetrazine-bridged system with the longer metal-metal distance exhibits much stronger metal-metal coupling than the bpym-bridged analog, a consequence of the very low lying \textgreek{p}* LUMO of tetrazines with high MO coeffs. at the coordinating N centers. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Gloeckle, Markus and Kaim, Wolfgang and Katz, Nestor E. and Posse, Monica Garcia and Cutin, Edgardo H. and Fiedler, Jan.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/28e2f987e1e023a3d30198c11e33af518/huebleriac}, doi = {10.1021/IC990249L}, interhash = {f7a3ea637057261ac5828dc4c1737e49}, intrahash = {8e2f987e1e023a3d30198c11e33af518}, issn = {0020-1669}, journal = {Inorganic Chemistry}, keywords = {bipyrimidine complex complex;iron complex;redn complex;redox complex;spectroelectrochem cyano dinuclear electrochem iron potential prepn;oxidn spectro tetrazinebispyridine}, number = 14, pages = {3270--3274}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {The FeIII/FeII vs. Fe22.5 Formulation in Mixed-Valent Species [(NC)4Fe(BL)Fe(CN)4]3-, BL = 2,2'-Bipyrimidine and 3,6-Bis(2-pyridyl)-1,2,4,5-tetrazine. Distance and Size Do Not Always Matter}, volume = 38, year = 1999 }