4479-74-7Relevant articles and documents
Specific chiral sensing of amino acids using induced circularly polarized luminescence of bis(diimine)dicarboxylic acid europium(III) complexes
Okutani, Kazuhiro,Nozaki, Koichi,Iwamura, Munetaka
, p. 5527 - 5537 (2014)
The circularly polarized luminescence (CPL) from [Eu(pda)2] - (pda = 1,10-phenanthroline-2,9-dicarboxylic acid) and [Eu(bda) 2]- (bda = 2,2-bipyridine-6,6-dicarboxylic acid) in aqueous solutions containing various amino acids was investigated. The europium(III) complexes exhibited bright-red luminescence assignable to the f-f transition of the EuIII ion when irradiated with UV light. Although the luminescence was not circularly polarized in the solid state or in aqueous solutions, in accordance with the achiral crystal structure, the complexes exhibited detectable induced CPL (iCPL) in aqueous solutions containing chiral amino acids. In the presence of l-pyrrolidonecarboxylic acid, both [Eu(pda) 2]- and [Eu(bda)2]- showed similar iCPL intensity (glum ～ 0.03 for the 5D0 → 7F1 transition at 1 mol·dm-3 of the amino acid). On the other hand, in the presence of l-histidine or l-arginine, [Eu(pda)2]- exhibited intense CPL (g lum ～ 0.08 for the 5D0 → 7F1 transition at 0.10 mol·dm-3 of the amino acid), whereas quite weak CPL was observed for [Eu(bda)2] - under the same conditions (glum 2]- was found to be a good chiral CPL probe with high sensitivity (about 10-2 mol·dm-3) and high selectivity for l-histidine at pH 3 and for l-arginine at pH 7. The mechanism of iCPL was evaluated by analysis of the fine structures in the luminescence spectra and the amino acid concentration dependence of glum. For the [Eu(pda)2]--histidine/arginine systems, the europium(III) complexes possess coordination structures similar to that in the crystal with slight distortion to form a chiral structure due to specific interaction with two zwitterionic amino acids. This mechanism was in stark contrast to that of the europium(III) complex-pyrrolidonecarboxylic acid system in which one amino acid coordinates to the EuIII ion to yield an achiral coordination structure.
Highly efficient G-quadruplex recognition by bisquinolinium compounds
De Cian, Anne,DeLemos, Elsa,Mergny, Jean-Louis,Teulade-Fichou, Marie-Paule,Monchaud, David
, p. 1856 - 1857 (2007)
Syntheses and telomeric G-quadruplex-DNA binding properties of novel bisquinolinium compounds are reported. This series exhibits remarkable efficiency both in terms of stabilization and selectivity, thus combining the performances of the most potent quadruplex binders reported so far. These bisquinolinium compounds then represent an ideal tradeoff between rapid synthetic access and efficient target recognition. The study also highlights important structural parameters that lead to the design of highly selective G-quadruplex binders. Copyright
Self-assembled bilayers as an anchoring strategy: Catalysts, chromophores, and chromophore-catalyst assemblies
Wang, Lei,Polyansky, Dmitry E.,Concepcion, Javier J.
supporting information, p. 8020 - 8027 (2019/06/13)
Anchoring strategies for immobilization of molecular catalysts, chromophores, and chromophorecatalyst assemblies on electrode surfaces play an important role in solar energy conversion devices such as dyesensitized solar cells and dye-sensitized photoelectrosynthesis cells. They are also important in interfacial studies with surface-bound molecules including electron-transfer dynamics and mechanistic studies related to small molecule activation catalysis. Significant progress has been made in this area, but many challenges remain in terms of stability, synthetic complexity, and versatility. We report here a new anchoring strategy based on selfassembled bilayers. This strategy takes advantage of noncovalent interactions between long alkyl chains chemically bound to a metal-oxide electrode surface and long alkyl chains on the molecule being anchored. The new methodology is applicable to the heterogenization of both catalysts and chromophores as well as to the in situ "synthesis" of chromophore-catalyst assemblies on the electrode surface.
X-ray crystallography and electrochemistry reveal electronic and steric effects of phosphine and phosphite ligands in complexes RuII(κ4-bda)(PR3)2 and RuII(κ3-bda)(PR3)3 (bda?=?2,2′-bipyridine-6,6′-dicarboxylato)
Yazdani, Sima,Silva, Braden E.,Cao, Thomas C.,Rheingold, Arnold L.,Grotjahn, Douglas B.
, p. 63 - 70 (2019/01/24)
We have examined coordination of PR3 = triphenylphosphine, triethylphosphine, triisopropyl phosphite, trimethyl phosphite, and 1,3,5-triaza-7-phosphaadamantane (PTA) to the fragment RuII(bda) to better understand how different phosphine and phosphite ligands influence the electronic and structural properties of the RuII complexes. PTA and P(OMe)3 afforded complexes with three phosphorus ligands bound to Ru, with the bda being tridentate (κ3-N,N,O) in complexes 4 and 5; for the other three phosphorus ligands, even in the presence of >2 equiv, only RuII(κ4-bda)(PR3)2 species 1–3 were seen. Both experimental and computational methods were used to study the complexes. Steric effects are the main factor determining whether bis- or tris(PR3) complexes are formed. Cyclic voltammetry studies of the complexes revealed an increase in RuIII/II potential upon having another phosphorus ligand in the equatorial position. Computational studies predict that the additional phosphine ligand in the equatorial plane of 4 engages in significant orbital mixing with the ruthenium center that results in lower energy bonding as compared to the axial phosphine ligands. This work provides the first evaluation of phosphorus ligand steric and electronic effects on the RuII(bda) fragment.
