%0 Journal Article %1 Mandal.2014 %A Mandal, Abhishek %A Agarwala, Hemlata %A Ray, Ritwika %A Plebst, Sebastian %A Mobin, Shaikh M. %A Priego, Jose Luis %A Jimenez-Aparicio, Reyes %A Kaim, Wolfgang %A Lahiri, Goutam Kumar. %D 2014 %J Inorganic Chemistry %K bipyridine complex complex;ESR complex;cyclic complex;prepn crystal diaminoanthraquinone diketonate dinuclear ruthenium structure voltammetry %N 12 %P 6082--6093 %R 10.1021/ic500452h %T Sensitivity of the Valence Structure in Diruthenium Complexes As a Function of Terminal and Bridging Ligands %V 53 %X The compds. (acac)2RuIII(m-H2L2-)RuIII(acac)2 (rac, 1, and meso, 1') and (bpy)2RuII(m-H2L.bul.-)RuII(bpy)2(ClO4)3 (meso, 2(ClO4)3) have been structurally, magnetically, spectroelectrochem., and computationally characterized (acac- = acetylacetonate, bpy = 2,2'-bipyridine, and H4L = 1,4-diamino-9,10-anthraquinone). The N,O;N',O'-coordinated m-H2Ln- forms two b-ketiminato-type chelate rings, and 1 or 1' are connected via NH···O hydrogen bridges in the crystals. 1 Exhibits a complex magnetic behavior, while 2(ClO4)3 is a radical species with mixed ligand/metal-based spin. The combination of redox noninnocent bridge (H2L0 $\rightarrow$ $\rightarrow$ $\rightarrow$ $\rightarrow$H2L4-) and (acac)2RuII $\rightarrow$ $\rightarrow$(acac)2RuIV or (bpy)2RuII $\rightarrow$ (bpy)2RuIII in 1/1' or 2 generates alternatives regarding the oxidn. state formulations for the accessible redox states (1n and 2n), which have been assessed by UV-visible-NIR, EPR, and DFT/TD-DFT calcns. The exptl. and theor. studies suggest variable mixing of the frontier orbitals of the metals and the bridge, leading to the following most appropriate oxidn. state combinations: (acac)2RuIII(m-H2L.bul.-)RuIII(acac)2+ (1+) $\rightarrow$ (acac)2RuIII(m-H2L2-)RuIII(acac)2 (1) $\rightarrow$ (acac)2RuIII(m-H2L.bul.3-)RuIII(acac)2-/(acac)2RuIII(m-H2L2-)RuII(acac)2- (1-) $\rightarrow$ (acac)2RuIII(m-H2L4-)RuIII(acac)22-/(acac)2RuII(m-H2L2-)RuII(acac)22- (12-) and (bpy)2RuIII(m-H2L.bul.-)RuII(bpy)24+ (24+) $\rightarrow$ (bpy)2RuII(m-H2L.bul.-)RuII(bpy)23+/(bpy)2RuII(m-H2L2-)RuIII(bpy)23+ (23+) $\rightarrow$ (bpy)2RuII(m-H2L2-)RuII(bpy)22+ (22+). The favoring of RuIII by s-donating acac- and of RuII by the p-accepting bpy coligands shifts the conceivable valence alternatives accordingly. Similarly, the introduction of the NH donor function in H2Ln as compared to O causes a cathodic shift of redox potentials with corresponding consequences for the valence structure. on SciFinder(R)

@article{Mandal.2014, abstract = {The compds. [(acac)2RuIII(\textgreek{m}-H2L2-)RuIII(acac)2] (rac, 1, and meso, 1') and [(bpy)2RuII(\textgreek{m}-H2L.bul.-)RuII(bpy)2](ClO4)3 (meso, [2](ClO4)3) have been structurally, magnetically, spectroelectrochem., and computationally characterized (acac- = acetylacetonate, bpy = 2,2'-bipyridine, and H4L = 1,4-diamino-9,10-anthraquinone). The N,O;N',O'-coordinated \textgreek{m}-H2Ln- forms two \textgreek{b}-ketiminato-type chelate rings, and 1 or 1' are connected via NH···O hydrogen bridges in the crystals. 1 Exhibits a complex magnetic behavior, while [2](ClO4)3 is a radical species with mixed ligand/metal-based spin. The combination of redox noninnocent bridge (H2L0 $\rightarrow$ $\rightarrow$ $\rightarrow$ $\rightarrow$H2L4-) and {(acac)2RuII} $\rightarrow$ $\rightarrow${(acac)2RuIV} or {(bpy)2RuII} $\rightarrow$ {(bpy)2RuIII} in 1/1' or 2 generates alternatives regarding the oxidn. state formulations for the accessible redox states (1n and 2n), which have been assessed by UV-visible-NIR, EPR, and DFT/TD-DFT calcns. The exptl. and theor. studies suggest variable mixing of the frontier orbitals of the metals and the bridge, leading to the following most appropriate oxidn. state combinations: [(acac)2RuIII(\textgreek{m}-H2L.bul.-)RuIII(acac)2]+ (1+) $\rightarrow$ [(acac)2RuIII(\textgreek{m}-H2L2-)RuIII(acac)2] (1) $\rightarrow$ [(acac)2RuIII(\textgreek{m}-H2L.bul.3-)RuIII(acac)2]-/[(acac)2RuIII(\textgreek{m}-H2L2-)RuII(acac)2]- (1-) $\rightarrow$ [(acac)2RuIII(\textgreek{m}-H2L4-)RuIII(acac)2]2-/[(acac)2RuII(\textgreek{m}-H2L2-)RuII(acac)2]2- (12-) and [(bpy)2RuIII(\textgreek{m}-H2L.bul.-)RuII(bpy)2]4+ (24+) $\rightarrow$ [(bpy)2RuII(\textgreek{m}-H2L.bul.-)RuII(bpy)2]3+/[(bpy)2RuII(\textgreek{m}-H2L2-)RuIII(bpy)2]3+ (23+) $\rightarrow$ [(bpy)2RuII(\textgreek{m}-H2L2-)RuII(bpy)2]2+ (22+). The favoring of RuIII by \textgreek{s}-donating acac- and of RuII by the \textgreek{p}-accepting bpy coligands shifts the conceivable valence alternatives accordingly. Similarly, the introduction of the NH donor function in H2Ln as compared to O causes a cathodic shift of redox potentials with corresponding consequences for the valence structure. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Mandal, Abhishek and Agarwala, Hemlata and Ray, Ritwika and Plebst, Sebastian and Mobin, Shaikh M. and Priego, Jose Luis and Jimenez-Aparicio, Reyes and Kaim, Wolfgang and Lahiri, Goutam Kumar.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2c83a56e622b2154013527d3795574a30/huebleriac}, doi = {10.1021/ic500452h}, interhash = {4804bcd205e55a7ba8457da1fe3c7e63}, intrahash = {c83a56e622b2154013527d3795574a30}, issn = {0020-1669}, journal = {Inorganic Chemistry}, keywords = {bipyridine complex complex;ESR complex;cyclic complex;prepn crystal diaminoanthraquinone diketonate dinuclear ruthenium structure voltammetry}, number = 12, pages = {6082--6093}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Sensitivity of the Valence Structure in Diruthenium Complexes As a Function of Terminal and Bridging Ligands}, volume = 53, year = 2014 }