Fine tuning of the electronic coupling between metal centers in cyano-bridged mixed-valent trinuclear complexes
We report the synthesis, characterization, and spectroscopic properties of a family of trinuclear cyano-bridged mixed-valent compounds, trans-[Ru IIL4{NCFeIII(CN)5}2] 4-, trans-[RuIIL4{CNFeIII(CN) 5}2]4-, and cis-[RuII(bpy) 2{NCFeIII(CN)5}2]4- (L = pyridine, 4-tert-butylpyridine, and 4-methoxypyridi...
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00201669_v43_n21_p6762_Albores |
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todo:paper_00201669_v43_n21_p6762_Albores2023-10-03T14:16:54Z Fine tuning of the electronic coupling between metal centers in cyano-bridged mixed-valent trinuclear complexes Alborés, P. Slep, L.D. Weyhermüller, T. Baraldo, L.M. ferric ion metal nitrile pyridine derivative rubidium tetraphenylphosphonium article chemical binding complex formation crystal structure electrochemistry electronics metal binding oxidation reduction reaction spectroscopy structure analysis substitution reaction synthesis We report the synthesis, characterization, and spectroscopic properties of a family of trinuclear cyano-bridged mixed-valent compounds, trans-[Ru IIL4{NCFeIII(CN)5}2] 4-, trans-[RuIIL4{CNFeIII(CN) 5}2]4-, and cis-[RuII(bpy) 2{NCFeIII(CN)5}2]4- (L = pyridine, 4-tert-butylpyridine, and 4-methoxypyridine). Tetraphenylphosphonium salts of complexes trans-[RuIIL4{NCFeIII(CN) 5}2]4- (L = pyridine and 4-tert-butylpyridine) crystallize in the space groups C2 and P2i/c, respectively, and show a linear arrangement of the metal units and an almost completely eclipsed configuration of the equatorial ligands. An intense band (ε ∼ 2000-9000 M-1 cm-1) is observed for all of the compounds in the NIR region of the spectrum, not present in the separated building blocks, and strongly solvent dependent. We assign it as a metal-to-metal charge transfer (MMCT) from the Ru(II) to the terminal Fe(III) moieties in the context of a simplified three-center model. The electrochemistry measurements reveal a splitting of the redox waves for the reduction of the iron centers for some of the complexes with a trans configuration between the metal units, ranging from 100 to 260 mV, depending on the substituting pyridine ligand and the solvent, suggesting long-range metal-metal interactions. These interactions are rationalized in terms of the energy matching between the π-symmetry orbitals of the metals and the cyanide bridge. The one- and two-electron reduced species derived from compounds trans-[RuIIL4{NCFe III(CN)5}2]4-,5-,6- were characterized in methanolic solution. The mixed-valent FeII-R II-FeIII system exhibits an intense red shifted band in the NIR region of the spectrum, arising from the superposition of MMCT bands from the central Ru(II) to the terminal Fe(III) fragments and from the 1 nm distant Fe(II) to Fe(III) centers. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00201669_v43_n21_p6762_Albores |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
ferric ion metal nitrile pyridine derivative rubidium tetraphenylphosphonium article chemical binding complex formation crystal structure electrochemistry electronics metal binding oxidation reduction reaction spectroscopy structure analysis substitution reaction synthesis |
| spellingShingle |
ferric ion metal nitrile pyridine derivative rubidium tetraphenylphosphonium article chemical binding complex formation crystal structure electrochemistry electronics metal binding oxidation reduction reaction spectroscopy structure analysis substitution reaction synthesis Alborés, P. Slep, L.D. Weyhermüller, T. Baraldo, L.M. Fine tuning of the electronic coupling between metal centers in cyano-bridged mixed-valent trinuclear complexes |
| topic_facet |
ferric ion metal nitrile pyridine derivative rubidium tetraphenylphosphonium article chemical binding complex formation crystal structure electrochemistry electronics metal binding oxidation reduction reaction spectroscopy structure analysis substitution reaction synthesis |
| description |
We report the synthesis, characterization, and spectroscopic properties of a family of trinuclear cyano-bridged mixed-valent compounds, trans-[Ru IIL4{NCFeIII(CN)5}2] 4-, trans-[RuIIL4{CNFeIII(CN) 5}2]4-, and cis-[RuII(bpy) 2{NCFeIII(CN)5}2]4- (L = pyridine, 4-tert-butylpyridine, and 4-methoxypyridine). Tetraphenylphosphonium salts of complexes trans-[RuIIL4{NCFeIII(CN) 5}2]4- (L = pyridine and 4-tert-butylpyridine) crystallize in the space groups C2 and P2i/c, respectively, and show a linear arrangement of the metal units and an almost completely eclipsed configuration of the equatorial ligands. An intense band (ε ∼ 2000-9000 M-1 cm-1) is observed for all of the compounds in the NIR region of the spectrum, not present in the separated building blocks, and strongly solvent dependent. We assign it as a metal-to-metal charge transfer (MMCT) from the Ru(II) to the terminal Fe(III) moieties in the context of a simplified three-center model. The electrochemistry measurements reveal a splitting of the redox waves for the reduction of the iron centers for some of the complexes with a trans configuration between the metal units, ranging from 100 to 260 mV, depending on the substituting pyridine ligand and the solvent, suggesting long-range metal-metal interactions. These interactions are rationalized in terms of the energy matching between the π-symmetry orbitals of the metals and the cyanide bridge. The one- and two-electron reduced species derived from compounds trans-[RuIIL4{NCFe III(CN)5}2]4-,5-,6- were characterized in methanolic solution. The mixed-valent FeII-R II-FeIII system exhibits an intense red shifted band in the NIR region of the spectrum, arising from the superposition of MMCT bands from the central Ru(II) to the terminal Fe(III) fragments and from the 1 nm distant Fe(II) to Fe(III) centers. |
| format |
JOUR |
| author |
Alborés, P. Slep, L.D. Weyhermüller, T. Baraldo, L.M. |
| author_facet |
Alborés, P. Slep, L.D. Weyhermüller, T. Baraldo, L.M. |
| author_sort |
Alborés, P. |
| title |
Fine tuning of the electronic coupling between metal centers in cyano-bridged mixed-valent trinuclear complexes |
| title_short |
Fine tuning of the electronic coupling between metal centers in cyano-bridged mixed-valent trinuclear complexes |
| title_full |
Fine tuning of the electronic coupling between metal centers in cyano-bridged mixed-valent trinuclear complexes |
| title_fullStr |
Fine tuning of the electronic coupling between metal centers in cyano-bridged mixed-valent trinuclear complexes |
| title_full_unstemmed |
Fine tuning of the electronic coupling between metal centers in cyano-bridged mixed-valent trinuclear complexes |
| title_sort |
fine tuning of the electronic coupling between metal centers in cyano-bridged mixed-valent trinuclear complexes |
| url |
http://hdl.handle.net/20.500.12110/paper_00201669_v43_n21_p6762_Albores |
| work_keys_str_mv |
AT alboresp finetuningoftheelectroniccouplingbetweenmetalcentersincyanobridgedmixedvalenttrinuclearcomplexes AT slepld finetuningoftheelectroniccouplingbetweenmetalcentersincyanobridgedmixedvalenttrinuclearcomplexes AT weyhermullert finetuningoftheelectroniccouplingbetweenmetalcentersincyanobridgedmixedvalenttrinuclearcomplexes AT baraldolm finetuningoftheelectroniccouplingbetweenmetalcentersincyanobridgedmixedvalenttrinuclearcomplexes |
| _version_ |
1807320707961454592 |