49669-13-8Relevant articles and documents
New nucleobase analogs for the extension of the triple helix recognition code
Lengeler,Weisz
, p. 1657 - 1658 (1999)
Molecular modeling was used to design novel nucleobases for the specific recognition of Watson-Crick base pairs within a triple helix. The synthesis for one of the nucleoside analogs is described in detail. Preliminary NMR measurements on the monomeric nucleobases in apolar solvents indicate preferred association modes and affinities towards a guanosine-cytidine Watson-Crick base pair.
A convenient preparative method for anionic tris(substituted pyrazolyl)methane ligands
Charbonnière, Lo?c J.,Ziessel, Raymond
, p. 6305 - 6307 (2003)
The synthesis of tris[3-(6-carboxypyridin-2-yl)pyrazol-1-yl]methane is described in a linear multi-step protocol. The pyridyl-pyrazolyl arms are first constructed before being condensed with chloroform. Careful study of the condensation reaction shows the presence of an isomeric form of the tris(pyrazolyl)methane derivative in which one of the pyrazolyl substituents is linked through the nitrogen atom at the 2 position of the pyrazol. After acid-catalysed isomerisation to the desired isomer, the intermediate compound was subjected to a carboalkoxylation reaction and a subsequent hydrolysis. These are some rare examples of reactions directly occurring on the tris(pyrazolyl)methane platforms.
A family of immobilizable chiral bis(pinenebipyridine) ligands
P?llnitz, Alpár,Skupienski, Radek,Stoeckli-Evans, Helen,Crochet, Aurélien,Silvestru, Anca,Fromm, Katharina M.,Mamula, Olimpia
, p. 2555 - 2558 (2013)
New enantiopure ligands containing two (-)-5,6-pinenebipyridine units connected by a bridge situated in position 6′ of the bipyridines have been prepared. The chemically addressable groups of the bridging (hydroxyl or keto) can be covalently bound to various supports in order to heterogenize the ligand. Georg Thieme Verlag Stuttgart · New York.
Iridium(III) Complexes Bearing a Formal Tetradentate Coordination Chelate: Structural Properties and Phosphorescence Fine-Tuned by Ancillaries
Yuan, Yi,Gnanasekaran, Premkumar,Chen, Yu-Wen,Lee, Gene-Hsiang,Ni, Shao-Fei,Lee, Chun-Sing,Chi, Yun
supporting information, p. 523 - 532 (2019/12/30)
Synthesis of the multidentate coordinated chelate N3C-H2, composed of a linked functional pyridyl pyrazole fragment plus a peripheral phenyl and pyridyl unit, was obtained using a multistep protocol. Preparation of Ir(III) metal complexes bearing a N3C chelate in the tridentate (κ3), tetradentate (κ4), and pentadentate (κ5) modes was executed en route from two nonemissive dimer intermediates [Ir(κ3-N3CH)Cl2]2 (1) and [Ir(κ4-N3C)Cl]2 (2). Next, a series of mononuclear Ir(III) complexes with the formulas [Ir(κ4-N3C)Cl(py)] (3), [Ir(κ4-N3C)Cl(dmap)] (4), [Ir(κ4-N3C)Cl(mpzH)] (5), and [Ir(κ4-N3C)Cl(dmpzH)] (6), as well as diiridium complexes [Ir2(κ5-N3C)(mpz)2(CO)(H)2] (7) and [Ir2(κ5-N3C)(dmpz)2(CO)(H)2] (8), were obtained upon treatment of dimer 2 with pyridine (py), 4-dimethylaminopyridine (dmap), 4-methylpyrazole (mpzH), and 3,5-dimethylpyrazole (dmpzH), respectively. These Ir(III) metal complexes were identified using spectroscopic methods and by X-ray crystallographic analysis of representative derivatives 3, 5, and 7. Their photophysical and electrochemical properties were investigated and confirmed by the theoretical simulations. Notably, green-emitting organic light-emitting diode (OLED) on the basis of Ir(III) complex 7 gives a maximum external quantum efficiency up to 25.1%. This result sheds light on the enormous potential of this tetradentate coordinated chelate in the development of highly efficient iridium complexes for OLED applications.
Realization of Highly Efficient Red Phosphorescence from Bis-Tridentate Iridium(III) Phosphors
Gnanasekaran, Premkumar,Yuan, Yi,Lee, Chun-Sing,Zhou, Xiuwen,Jen, Alex K.-Y.,Chi, Yun
supporting information, p. 10944 - 10954 (2019/09/09)
Bis-tridentate Ir(III) metal complexes bring forth interesting photophysical properties, among which the orthogonal arranged, planar tridentate chelates could increase the emission efficiency due to the greater rigidity and, in the meantime, allow strong interligand stacking that could deteriorate the emission efficiency. We bypassed this hurdle by design of five bis-tridentate Ir(III) complexes (1-5), to which both of their monoanionic ancillary and dianionic chromophoric chelate were functionalized derivative of 2-pyrazolyl-6-phenylpyridine, i.e. pzpyphH2 parent chelate. Hence, addition of phenyl substituent to the pyrazolyl fragment of pzpyphH2 gave rise to the precursors of monoanionic chelate (A1H-A3H), on which the additional tert-butyl and/or methoxy groups were introduced at the selected positions for tuning their steric and electronic properties, while precursors of dianionic chelates was judiciously prepared with an isoquniolinyl central unit on pziqphH2 in giving the red-shifted emission (cf. L1H2 and L2H2). Factors affected their photophysical properties were discussed by theoretical methods based on DFT and TD-DFT calculation, confirming that the T1 excited state of all investigated Ir(III) complexes shows a mixed metal-to-ligand charge transfer (MLCT), intraligand charge transfer (ILCT), ligand-to-ligand charge transfer (LLCT), and ligand-centered (LC) transition character. In contrast, the poor quantum yield of 3 is due to the facilitation of the nonradiative decay in comparison to the radiative process. As for potential OLED applications, Ir(III) complex 2 gives superior performance with max. efficiencies of 28.17%, 41.25 cd·A-1 and 37.03 lm·W-1, CIEx,y = 0.63, 0.37 at 50 mA cm-2, and small efficiency roll-off.
