Volume 2015, Issue 5 p. 786-793
Full Paper

Homoleptic and Heteroleptic Ruthenium(II) Complexes Based on 2,6-Bis(quinolin-2-yl)pyridine Ligands – Multiple-Charged-State Modules for Potential Density Memory Storage

Ion Marin

Ion Marin

Institute of Chemistry, Academy of Sciences of Moldova, 3, Academiei str., Chisinau, MD-2028, Republic of Moldova

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Constantin Turta

Constantin Turta

Institute of Chemistry, Academy of Sciences of Moldova, 3, Academiei str., Chisinau, MD-2028, Republic of Moldova

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Andrew C. Benniston

Corresponding Author

Andrew C. Benniston

Molecular Photonics Laboratory, School of Chemistry, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK, http://www.ncl.ac.uk/mpl/

Molecular Photonics Laboratory, School of Chemistry, Newcastle University, Newcastle upon Tyne, NE1 7RU, UKSearch for more papers by this author
Ross W. Harrington

Ross W. Harrington

Crystallography Laboratory, School of Chemistry, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK

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William Clegg

William Clegg

Crystallography Laboratory, School of Chemistry, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK

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First published: 12 January 2015
Citations: 4

Graphical Abstract

The ligands diethyl 2,2′-(pyridine-2,6-diyl)bis(quinolone-4-carboxylate) (L2) and 2,6-bis(4-methylquinolin-2-yl)pyridine (L1) were used to prepare the homoleptic [Ru(L1)2][PF6]2 (RU1) and heteroleptic [Ru(L1)(L2)][PF6]2 (RU2) complexes. Electrochemistry experiments showed that the complexes can hold up to five electrons reversibly.

Abstract

The two ligands 2,6-bis(4-methylquinolin-2-yl)pyridine (L1) and diethyl 2,2′-(pyridine-2,6-diyl)bis(quinolone-4-carboxylate) (L2) were used to prepare the homoleptic [Ru(L2)2][PF6]2 (RU1) and heteroleptic [Ru(L1)(L2)][PF6]2 (RU2) complexes. DFT calculations (B3PW91,3-21G**) performed on both RU1 and RU2 revealed that redox at the ruthenium site for RU2 is less positive by ca. 110 mV. Consequently, the one-electron ligand-based reduction for RU2 is more cathodic by 80 mV. Electrochemistry experiments confirmed that the prediction is qualitatively correct and that the complexes can each hold up to five electrons reversibly.