4073-72-7Relevant articles and documents
Cationic Iridium Complexes with 3,4,5-Triphenyl-4 H-1,2,4-Triazole Type Cyclometalating Ligands: Synthesis, Characterizations, and Their Use in Light-Emitting Electrochemical Cells
Bai, Rubing,Chen, Mengzhen,He, Lei,Meng, Xianwen
, (2020/08/05)
Cationic iridium complexes that show blue-shifted emission and high phosphorescent efficiency have been pursued for their optoelectronic applications. Five cationic iridium complexes with 3,4,5-triphenyl-4H-1,2,4-triazole (tPhTAZ) type cyclometalating ligands (C^N) and 2,2′-bipyridine or 2-(pyridin-2-yl)-1H-benzo[d]imidazole type ancillary ligands (N^N) have been designed and synthesized. Their structures have been confirmed by X-ray crystallography, and their photophysical and electrochemical properties have been comprehensively characterized. In solution and thin films, the complexes afford efficient yellow to blue-green emission. The highest occupied molecular orbitals (HOMOs) of these complexes are delocalized over the C^N ligand and the iridium ion, and compared with the conventional 2-phenylpyridine (Hppy) ligand, the tPhTAZ ligand largely shifts the emission of the complex toward blue by over 40 nm through stabilizing the HOMO. Moreover, the peripheral phenyl rings in tPhTAZ provide steric hindrance to the complexes, which suppresses phosphorescence concentration-quenching of the complexes, leading to high luminescent efficiencies in neat films. Theoretical calculations have shown that the emission of the complexes originates from either the charge-transfer state (Ir/C^N → N^N) or the C^N/N^N-centered 3π-π? state, depending on the local surrounding of the complex. The complexes exhibit good electrochemical stability with reversible oxidation and reduction processes in solution. Solid-state light emitting electrochemical cells (LECs) using the complexes afford yellow to blue-green emission, with peak current efficiencies of up to 34.7 cd A-1 and maximum brightness of up to 256 cd m-2 at 3.0 V, which are among the highest for LECs based on cationic iridium complexes reported so far, indicating the great potential for the use of tPhTAZ-type C^N ligands in construction of cationic iridium complexes for LEC applications.
A simple and efficient synthesis of 3,4,5-trisubstituted/N-fused 1,2,4-triazoles via ceric ammonium nitrate catalyzed oxidative cyclization of amidrazones with aldehydes using polyethylene glycol as a recyclable reaction medium
Nakka, Mangarao,Tadikonda, Ramu,Rayavarapu, Srinuvasarao,Sarakula, Prasanthi,Vidavalur, Siddaiah
, p. 517 - 525 (2015/02/19)
An environmentally benign protocol is described for the synthesis of 3,4,5-trisubstituted 1,2,4-triazoles and N-fused 1,2,4-triazoles via ceric ammonium nitrate catalyzed oxidative cyclization of amidrazones and aldehydes using polyethylene glycol as recyclable reaction medium. This protocol is effective toward various substrates having different functionalities. The easy recyclability of the reaction medium makes the process economic and potentially viable for commercial applications.
Br?nsted acid-catalyzed simple and efficient synthesis of 1,2,4-triazoles and 1,2,4-oxadiazoles using 2,2,2-trichloroethyl imidates in PEG
Mangarao, Nakka,Mahaboob Basha, Gajula,Ramu, Tadikonda,Srinuvasarao, Rayavarapu,Prasanthi, Sarakula,Siddaiah, Vidavalur
supporting information, p. 177 - 179 (2014/01/06)
A facile and highly efficient synthesis of 3,4,5-trisubstituted 1,2,4-triazoles and 3,5-disubstituted 1,2,4-oxadiazoles from 2,2,2-trichloroethyl imidates using PEG as a solvent and employing PTSA as the catalyst under mild conditions is described.
