A dinuclear [{(p-cym)RuIICl}2(μ-bpytz˙−)]+ complex bridged by a radical anion: synthesis, spectroelectrochemical, EPR and theoretical investigation (bpytz = 3,6-bis(3,5-dimethylpyrazolyl)1,2,4,5-tetrazine; p-cym = p-cymene)
| Autor: | Sebastian Plebst, Kousik Samanta, Suman Kumar Tripathy, Margarethe van der Meer, Paltan Laha, Biprajit Sarkar, Srikanta Patra, Niranjan Dehury, Anupam Sahoo |
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| Rok vydání: | 2016 |
| Předmět: |
010405 organic chemistry
Chemistry Ligand Bridging ligand 010402 general chemistry Electrochemistry Photochemistry 01 natural sciences 0104 chemical sciences law.invention Inorganic Chemistry Metal Tetrazine chemistry.chemical_compound Paramagnetism Crystallography law visual_art visual_art.visual_art_medium Density functional theory Electron paramagnetic resonance |
| Zdroj: | Dalton Transactions. 45:12532-12538 |
| ISSN: | 1477-9234 1477-9226 |
| DOI: | 10.1039/c6dt01995a |
| Popis: | The reaction of the chloro-bridged dimeric precursor [{(p-cym)Ru(II)Cl}(μ-Cl)]2 (p-cym = p-cymene) with the bridging ligand 3,6-bis(3,5-dimethylpyrazolyl)-1,2,4,5-tetrazine (bpytz) in ethanol results in the formation of the dinuclear complex [{(p-cym)Ru(II)Cl}2(μ-bpytz˙(-))](+), [1](+). The bridging tetrazine ligand is reduced to the anion radical (bpytz˙(-)) which connects the two Ru(II) centres. Compound [1](PF6) has been characterised by an array of spectroscopic and electrochemical techniques. The radical anion character has been confirmed by magnetic moment (corresponding to one electron paramagnetism) measurement, EPR spectroscopic investigation (tetrazine radical anion based EPR spectrum) as well as density functional theory based calculations. Complex [1](+) displays two successive one electron oxidation processes at 0.66 and 1.56 V versus Ag/AgCl which can be attributed to [{(p-cym)Ru(II)C}2(μ-bpytz˙(-))](+)/[{(p-cym)Ru(II)Cl}2(μ-bpytz)](2+) and [{(p-cym)Ru(II)Cl}2(μ-bpytz)](+)/[{(p-cym)Ru(III)Cl}2(μ-bpytz)](2+) processes (couples I and II), respectively. The reduction processes (couple III-couple V), which are irreversible, likely involve the successive reduction of the bridging ligand and the metal centres together with loss of the coordinated chloride ligands. UV-Vis-NIR spectroelectrochemical investigation reveals typical tetrazine radical anion containing bands for [1](+) and a strong absorption in the visible region for the oxidized form [1](2+), which can be assigned to a Ru(II) → π* (tetrazine) MLCT transition. The assignment of spectroscopic bands was confirmed by theoretical calculations. |
| Databáze: | OpenAIRE |
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