Effect of free rotation in polypyridinic ligands of Ru(ii) complexes applied in light-emitting electrochemical cells

Paulina Dreyse, Bárbara Loeb, Marco Soto-Arriaza, Daniel Tordera, Enrique Ortí, Juan J. Serrano-Pérez, Henk J. Bolink

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

In the present work we report the synthesis and the electrochemical, photoluminescent and electroluminescent properties of two new Ru(ii) complexes described by the general formula [Ru(phen)2X]2+, where phen is 1,10-phenanthroline. The X ligand consists of a 2,2′-bipyridine (bpy) unit substituted with two phenyl rings connected to the bpy core through a saturated (Lhydro = 4,4′-diphenylethyl-2,2′-bipyridine) or a conjugated (LH = 4,4′-bis(α-styrene)-2,2′-bipyridine) carbon-carbon bridge. The photoluminescent spectra indicate that, both in solution and solid state, the complex bearing the aliphatic substitution bridges exhibits a higher quantum yield and a longer excited state lifetime than the fully conjugated complex. The new complexes were used in light-emitting electrochemical cells (LECs) showing red emission for the complex with the Lhydro ligand and no light emission for the complex incorporating the LH ligand. This and the photophysical properties make it plausible that for these complexes the degree of freedom increases with aliphatic substitution. As a consequence, the negative effect of the auto-quenching processes taking place in solid LEC devices due to the close molecular packing is limited. When compared with the archetype [Ru(phen)3]2+complex, the complex with aliphatic substitution shows better performance in the device supporting the beneficial effect of the bulky substitution. © 2013 The Royal Society of Chemistry.
Original languageEnglish
Pages (from-to)15502-15513
Number of pages12
JournalDalton Transactions
DOIs
Publication statusPublished - 21 Nov 2013
Externally publishedYes

Fingerprint Dive into the research topics of 'Effect of free rotation in polypyridinic ligands of Ru(ii) complexes applied in light-emitting electrochemical cells'. Together they form a unique fingerprint.

  • Cite this

    Dreyse, P., Loeb, B., Soto-Arriaza, M., Tordera, D., Ortí, E., Serrano-Pérez, J. J., & Bolink, H. J. (2013). Effect of free rotation in polypyridinic ligands of Ru(ii) complexes applied in light-emitting electrochemical cells. Dalton Transactions, 15502-15513. https://doi.org/10.1039/c3dt52067f