Three new bis-cyclometalated iridium(III) complexes, of general formula [Ir(2-phenylpyridine)2(L)]+, are reported. The compounds contain a dipyridine-type ligand (L) derived from di-2-pyridylketone(dipyridin-2-ylmethanol, 2,2¢-(hydrazonomethylene)dipyridine and 3-hydroxy-3,3-di(pyridine-2-yl)propanenitrile) and were synthesized through two different reaction pathways. The alternative synthetic pathway herein proposed, namely the direct reactions on the complex [Ir(2-phenylpyridine)2(2,2¢-dipyridylketone)]+, overcame the inconveniences encountered with the standard reaction between the dimeric precursor [Ir(2-phenylpyridine)2(m-Cl)]2 and the ancillary ligands (L). The photophysical characterization of the iridium complexes reveals that modifications on the ancillary ligand introduce large changes in the photophysical behaviour of the complexes. High emission quantum yield is associated with the presence of a saturated carbon between the two pyridyl moieties: [Ir(2-phenylpyridine)2(2,2¢-dipyridylketone)]+ and [Ir(2-phenylpyridine)2(2,2¢-(hydrazonomethylene)dipyridine)]+ are extremely low emissive, while [Ir(2-phenylpyridine)2(dipyridin-2-ylmethanol)]+ and [Ir(2-phenylpyridine)2(3-hydroxy-3,3-di(pyridine-2-yl)propanenitrile)]+ are good photoemitters. DFT and TD-DFT calculations confirmed the mixed LC/MLCT character of the excited states involved in the absorption and emission processes and highlighted the role of the p-conjugation between the two subunits of the ancillary ligand in determining the nature of the LUMO.

Dipyridylketone as a versatile ligand precursor for new cationic heteroleptic cyclometalated iridium complexes

VOLPI, GIORGIO;GARINO, Claudio;GOBETTO, Roberto;NERVI, Carlo
2012-01-01

Abstract

Three new bis-cyclometalated iridium(III) complexes, of general formula [Ir(2-phenylpyridine)2(L)]+, are reported. The compounds contain a dipyridine-type ligand (L) derived from di-2-pyridylketone(dipyridin-2-ylmethanol, 2,2¢-(hydrazonomethylene)dipyridine and 3-hydroxy-3,3-di(pyridine-2-yl)propanenitrile) and were synthesized through two different reaction pathways. The alternative synthetic pathway herein proposed, namely the direct reactions on the complex [Ir(2-phenylpyridine)2(2,2¢-dipyridylketone)]+, overcame the inconveniences encountered with the standard reaction between the dimeric precursor [Ir(2-phenylpyridine)2(m-Cl)]2 and the ancillary ligands (L). The photophysical characterization of the iridium complexes reveals that modifications on the ancillary ligand introduce large changes in the photophysical behaviour of the complexes. High emission quantum yield is associated with the presence of a saturated carbon between the two pyridyl moieties: [Ir(2-phenylpyridine)2(2,2¢-dipyridylketone)]+ and [Ir(2-phenylpyridine)2(2,2¢-(hydrazonomethylene)dipyridine)]+ are extremely low emissive, while [Ir(2-phenylpyridine)2(dipyridin-2-ylmethanol)]+ and [Ir(2-phenylpyridine)2(3-hydroxy-3,3-di(pyridine-2-yl)propanenitrile)]+ are good photoemitters. DFT and TD-DFT calculations confirmed the mixed LC/MLCT character of the excited states involved in the absorption and emission processes and highlighted the role of the p-conjugation between the two subunits of the ancillary ligand in determining the nature of the LUMO.
2012
41
1065
1073
Giorgio Volpi; Claudio Garino; Emanuele Breuza; Roberto Gobetto; Carlo Nervi
File in questo prodotto:
File Dimensione Formato  
Ir Dalton_1.pdf

Accesso riservato

Tipo di file: PDF EDITORIALE
Dimensione 653.38 kB
Formato Adobe PDF
653.38 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
Ir_Dipyridylketone.docx

Open Access dal 23/01/2013

Tipo di file: POSTPRINT (VERSIONE FINALE DELL’AUTORE)
Dimensione 536.63 kB
Formato Microsoft Word XML
536.63 kB Microsoft Word XML Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/96563
Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 13
  • ???jsp.display-item.citation.isi??? 14
social impact