Unprecedented Ir(III) cationic complexes based on tridentate tetrazolate ligands: synthesis, photophysics and encapsulation in SiO2 nanoparticles
Metadatos
Afficher la notice complèteAuteur
Troya, José; Quesada Moreno, María del Mar; Jiménez Gallego, Juan Ramón; Herrera Martínez, Juan ManuelEditorial
Royal Society of Chemistry
Date
2023-01-24Referencia bibliográfica
New J. Chem., 2023, 47, 4577. DOI: [10.1039/d2nj06037j]
Patrocinador
MCIN/AEI PGC2018-102052-B-C21 A-FQM-172-UGR18 B.FQM.328.UGR20; Junta de Andalucia FJC2018-035709-I DOC_01282; FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades IJC2020-044040-I FQM-195; University of GranadaRésumé
The first examples of luminescence Ir(III) complexes derived from a tridentate tetrazole ligand, 2-(tetrazole-
5-yl)-1,10-phenanthroline (Hphenttz), are reported here. Two cationic complexes, heteroleptic [Ir(tpy)
(phenttz)]2+ (1) (tpy = 2,20:60,200-terpyridine) and homoleptic [Ir(phenttz)2]+(2), have been synthesized and fully
characterized from a chemical, structural and photophysical point of view. Both complexes exhibit green
luminescence with a prevalent 3LC (Ligand-Centered) character, which is evidenced by their structured
emission profiles and low kr values (of about 103 s 1), and supported by density functional theory (DFT) and
time-dependent density functional theory (TD-DFT) calculations. In air-equilibrated solutions, 1 and 2 show
emission lifetimes (respective values of 1.6 ms and 1.2 ms) comparable to that of the reference complex
[Ir(tpy)2]3+ (1.0 ms) and quantum yields slightly lower (1.5% (1), 1.3% (2)) than that obtained for [Ir(tpy)2]3+
(2.5%). Under an oxygen-free atmosphere, the emission lifetimes and quantum yields (t/F) of the complexes
increase significantly up to 5 ms/4.2% (1) and 3 ms/3.3% (2). 1 has been embedded within amorphous silica
nanoparticles leading to the hybrid material 1@SiO2. This material shows enhanced photochemical stability
and higher luminescence efficiency compared to the free complex, which demonstrates that silica hampers
the diffusion of O2, restrains the mobility of the complex and stimulates the radiative decay of the
excited state.