The role of substituents on functionalized 1,10-phenanthroline in controlling the emission properties of cationic iridium(III) complexes of interest for electroluminescent devices.
The photophysical and electrochemical properties of the novel complexes [Ir(ppy)(2)(5-X-1,10-phen)][PF(6)] (ppy = 2-phenylpyridine, phen = phenanthroline, X = NMe(2), NO(2)), [Ir(pq)(2)(5-X-1,10-phen)][PF(6)] (pq = 2-phenylquinoline, X = H, Me, NMe(2), NO(2)), [Ir(ppy)2(4-Me,7-Me-1,10-phen)][PF(6)], [Ir(ppy)2(5-Me,6-Me-1,10-phen)][PF(6)], [Ir(ppy)(2)(2-Me,9-Me-1,10-phen)][PF(6)], and [Ir(pq)2(4-Ph,7-Ph-1,10-phen)][PF(6)] have been investigated and compared with those of the known reference complexes [Ir(ppy)(2)(4-Me or 5-H or 5-Me-1,10-phen)][PF(6)] and [Ir(ppy)(2)(4-Ph,7-Ph-1,10-phen)][PF(6)], showing how the nature and number of the phenanthroline substituents tune the color of the emission, its quantum yield, and the emission lifetime. It turns out that the quantum yield is strongly dependent on the nonradiative decay. The geometry, ground state, electronic structure, and excited electronic states of the investigated complexes have been calculated on the basis of density functional theory (DFT) and time-dependent DFT approaches, thus substantiating the electrochemical measurements and providing insight into the electronic origin of the absorption spectra and of the lowest excited states involved in the light emission process. These results provide useful guidelines for further tailoring of the photophysical properties of ionic Ir(III) complexes.
Dragonetti
Claudia
C
Dipartimento di Chimica Inorganica, Metallorganica e Analitica, Dipartimento di Chimica Fisica ed Elettrochimica, Centro di Eccellenza CIMAINA dell'Università di Milano, Istituto di Scienze e Tecnologie Molecolari, Milano, Italy.
Falciola
Luigi
L
Mussini
Patrizia
P
Righetto
Stefania
S
Roberto
Dominique
D
Ugo
Renato
R
Valore
Adriana
A
De Angelis
Filippo
F
Fantacci
Simona
S
Sgamellotti
Antonio
A
Ramon
Miguel
M
Muccini
Michele
M