- Substituents engineered deep-red to near-infrared phosphorescence from tris-heteroleptic iridium(iii) complexes for solution processable red-NIR organic light-emitting diodes
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Research on near-infrared- (NIR-) emitting materials and devices has been propelled by fundamental and practical application demands surrounding information-secured devices and night-vision displays to phototherapy and civilian medical diagnostics. However, the development of stable, highly efficient, low-cost NIR-emitting luminophores is still a formidable challenge owing to the vulnerability of the small emissive bandgap toward several nonradiative decay pathways, including the overlapping of ground- and excited-state vibrational energies and high-frequency oscillators. Suitable structural designs are mandatory for producing an intense NIR emission. Herein, we developed a series of deep-red to NIR emissive iridium(iii) complexes (Ir1-Ir4) to explore the effects of electron-donating and electron-withdrawing substituents anchored on the quinoline moiety of (benzo[b]thiophen-2-yl)quinoline cyclometalating ligands. These substituents help engineer the emission bandgap systematically from the deep-red to the NIR region while altering the emission efficiencies drastically. Single-crystal X-ray structures authenticated the exact coordination geometry and intermolecular interactions in these new compounds. We also performed an in-depth and comparative photophysical study in the solution, neat powder, doped polymer film, and freeze matrix at 77 K states to investigate the effects of substitution on the excited-state properties. These studies were conducted in conjunction with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. Most importantly, the -CH3 substituted Ir1, unsubstituted Ir2, and -CF3 substituted complex (Ir4) were promising novel compounds with bright phosphorescence quantum efficiency in doped polymer films. Using these novel molecules, deep-red to NIR emissive organic light-emitting diodes (OLEDs) were fabricated using a solution-processable method. The unoptimized device exhibited maximum external quantum efficiency (EQE) values of 2.05% and 2.11% for Ir1 and Ir2, respectively.
- Kim, Hae Un,Sohn, Sunyoung,Choi, Wanuk,Kim, Minjun,Ryu, Seung Un,Park, Taiho,Jung, Sungjune,Bejoymohandas
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p. 10640 - 10658
(2018/10/24)
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- Construction and functionalization of fused pyridine ring leading to novel compounds as potential antitubercular agents
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A series of fused and functionalized pyridine derivatives were designed, synthesized and tested for their potential antitubercular properties. All these novel compounds were prepared by using multistep methods involving the construction of pyridine ring as a key synthetic step. Some of these compounds were found to be interesting when tested for their antitubercular properties in vitro and one of them appeared as an attractive and potential antitubercular agent.
- Dulla, Balakrishna,Wan, Baojie,Franzblau, Scott G.,Kapavarapu, Ravikumar,Reiser, Oliver,Iqbal, Javed,Pal, Manojit
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p. 4629 - 4635
(2012/07/31)
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- Further studies on the interaction of the 5-hydroxytryptamine3 (5-HT3) receptor with arylpiperazine ligands. Development of a new 5-HT3 receptor ligand showing potent acetylcholinesterase inhibitory properties
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Novel arylpiperazine derivatives bearing lipophilic probes were designed, synthesized, and evaluated for their potential ability to interact with the 5-hydroxytryptamine3 (5-HT3) receptor. Most of the new compounds show subnanomolar 5-HT3 receptor affinity. Ester 6bc showing a picomolar Ki value is one of the most potent 5-HT 3 receptor ligands so far synthesized. The structure-affinity relationship study suggests the existence of a certain degree of conformational freedom of the amino acid residues interacting with the substituents in positions 3 and 4 of the quipazine quinoline nucleus. Thus, the tacrine-related heterobivalent ligand 60 was designed in an attempt to capitalize on the evidence of such a steric tolerance. Compound 6o shows a nanomolar potency for both the 5-HT3 receptor and the human AChE and represents the first example of a rationally designed high-affinity 5-HT3 receptor ligand showing nanomolar AChE inhibitory activity. Finally, the computational analysis performed on compound 6o allowed the rationalization of the structure-energy determinants for AChE versus BuChE selectivity and revealed the existence of a subsite at the boundary of the 5-HT3 receptor extracellular domain, which could represent a "peripheral" site similar to that evidenced in the AChE gorge.
- Cappelli, Andrea,Gallelli, Andrea,Manini, Monica,Anzini, Maurizio,Mennuni, Laura,Makovec, Francesco,Menziani, M. Cristina,Alcaro, Stefano,Ortuso, Francesco,Vomero, Salvatore
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p. 3564 - 3575
(2007/10/03)
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