A Valence Tautomeric Dinuclear Copper Tetrakisguanidine Complex |
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Authors: | Sven Wiesner Dr Arne Wagner Dr Elisabeth Kaifer Prof Hans‐Jörg Himmel |
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Institution: | Anorganisch-Chemisches Institut, Ruprecht-Karls Universit?t Heidelberg, Heidelberg, Germany |
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Abstract: | We report on the first valence tautomeric dinuclear copper complex, featuring 2,3,5,6‐tetrakis(tetramethylguanidino)pyridine as a bridging redox‐active GFA (guanidino‐functionalized aromatic) ligand. The preferred electronic structure of the complex is massively influenced by the environment. In the solid state and in nonpolar solvents a paramagnetic, dinuclear CuII complex with a neutral GFA ligand is present. In polar solvents, the electronic structure changes to a diamagnetic, dinuclear CuI complex with a twofold‐oxidized GFA ligand. Using acetone as a solvent, both electronic structures are accessible due to a temperature‐dependent equilibrium between the two valence tautomeric complexes. Our results pave the way for a broader use of valence tautomeric transition‐metal complexes in catalytic reactions since anionic coligands can now be tolerated owing to the neutral/positively charged GFA ligand. |
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Keywords: | coordination compounds copper electronic structures guanidine valence tautomers |
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