Efficient Energy Transfer and Metal Coupling in Cyanide-Bridged Heterodinuclear Complexes Based on (Bipyridine)(terpyridine)ruthenium(II) and (Phenylpyridine)iridium(III) Complexes

Barthelmes, Kevin; Jäger, Michael; Kübel, Joachim; Friebe, Christian; Winter, Andreas; Wächtler, Maria; Dietzek, Benjamin; Schubert, Ulrich S.

Abstract:

We report a series of cyanide-bridged, heterodinuclear iridium(III)–ruthenium(II) complexes with the generalized formula [Ir((R2)2-ppy)2(CN)(μ-CN)Ru(bpy)(tpy-R1)]PF6 (ppy = 2-phenylpyridine, bpy = 2,2′-bipyridine, and tpy = 2,2′:6′,2″-terpyridine). The structural, spectroscopic, and electrochemical properties were analyzed in the context of variation of the electron-withdrawing (e.g., −F, −Br, −CHO) and -donating (e.g., −Me) and extended π-conjugated groups at several positions. In total, ten dinuclear complexes and the appropriate model complexes have been prepared. The iridium(III)-based emission is almost fully quenched in these complexes, and only the ruthenium(II)-based emission is observed, which indicates an efficient energy transfer toward the Ru center. Upon oxidation of the Ru center, the fluorinated complexes 2 exhibit a broad intervalence charge-transfer transition in the near-infrared region. The complexes are assigned to a weakly coupled class II system according to the Robin–Day classification. The electronic structure was evaluated by density functional theory (DFT) and time-dependent DFT calculations to corroborate the experimental data.

Research areas:

• Supramolecular Chemistry

Year:

2016

Type of Publication:

Article

Journal:

Inorganic Chemistry

Volume:

55

Pages:

5152 - 5167

DOI:

10.1021/acs.inorgchem.5b02919