89980-97-2Relevant academic research and scientific papers
Effects of the Polyelectrolyte Poly(vinyl sulfate) on the Photosensitized Electron-Transfer Reactions of Tris(2,2'-bipyridine)ruthenium(II) with a Dipolar Zwitterionic Viologen
Sassoon, Richard E.,Aizenshtat, Ze'ev,Rabani, Joseph
, p. 1182 - 1190 (1985)
The photosensitized electron-transfer system containing Ru(bpy)32+ as photosensitizer and N,N'-bis(4-sulfonatotolyl)-4,4'-bipyridyldiylium (BSV) as quencher was investigated in aqueous solutions containing the polyelectrolyte poly(vinyl sulfate) (PVS).This is the first system where acceleration of the forward quenching reaction together with considerable retardation of the reaction regenerating the ground-state species occurs on addition of a charged microenvironment.Both the BSV molecule, possessing a large dipole moment, and the Ru(bpy)32+ cation are concentrated in the polyelectrolyte field and steady-state emission experiments showed that the distribution of BSV in the potential field of PVS may be described by the Poisson-Boltzmann equation.The reaction between BSV and Ru(bpy)32+ results in an electron transfer, yielding BSV-. and Ru(bpy)33+ as products.There is evidence for formation of an outer-sphere complex between BSV-. and Ru(bpy)33+.The yields of electron transfer were hardly affected by the presence of PVS although the rate of the reverse electron-transfer reaction was somewhat reduced.This was attributed to the distribution of charge over the BSV-. radical anion product.The effects of pH, addition of an inert salt, and variation of coverage of the polyelectolyte were also investigated for the system.
A scalable procedure for light-induced benzylic brominations in continuous flow
Cantillo, David,De Frutos, Oscar,Rincon, Juan A.,Mateos, Carlos,Oliver Kappe
supporting information, p. 223 - 229 (2014/01/17)
A continuous-flow protocol for the bromination of benzylic compounds with N-bromosuccinimide (NBS) is presented. The radical reactions were activated with a readily available household compact fluorescent lamp (CFL) using a simple flow reactor design based on transparent fluorinated ethylene polymer (FEP) tubing. All of the reactions were carried out using acetonitrile as the solvent, thus avoiding hazardous chlorinated solvents such as CCl4. For each substrate, only 1.05 equiv of NBS was necessary to fully transform the benzylic starting material into the corresponding bromide. The general character of the procedure was demonstrated by brominating a diverse set of 19 substrates containing different functional groups. Good to excellent isolated yields were obtained in all cases. The novel flow protocol can be readily scaled to multigram quantities by operating the reactor for longer time periods (throughput 30 mmol h-1), which is not easily possible in batch photochemical reactors. The bromination protocol can also be performed with equal efficiency in a larger flow reactor utilizing a more powerful lamp. For the bromination of phenylacetone as a model, a productivity of 180 mmol h -1 for the desired bromide was achieved.
Visible light-induced hole injection into rectifying molecular wires anchored on Co3O4 and SiO2 nanoparticles
Soo, Han Sen,Agiral, Anil,Bachmeier, Andreas,Frei, Heinz
, p. 17104 - 17116 (2013/01/15)
Tight control of charge transport from a visible light sensitizer to a metal oxide nanoparticle catalyst for water oxidation is a critical requirement for developing efficient artificial photosynthetic systems. By utilizing covalently anchored molecular w
Structure-activity relationship studies on N3-substituted willardiine derivatives acting as AMPA or kainate receptor antagonists
Dolman, Nigel P.,More, Julia C. A.,Alt, Andrew,Knauss, Jody L.,Troop, Helen M.,Bleakman, David,Collingridge, Graham L.,Jane, David E.
, p. 2579 - 2592 (2007/10/03)
N3-Substitution of the uracil ring of willardiine with a variety of carboxyalkyl or carboxybenzyl substituents produces AMPA and kainate receptor antagonists. In an attempt to improve the potency and selectivity of these AMPA and kainate receptor antagonists a series of analogues with different terminal acidic groups and interacidic group spacers was synthesized and pharmacologically characterized. (5′)-1-(2-Amino-2-carboxyethyl)-3-(2- carboxythiophene-3-ylmethyl)pyrimidine-2,4-dione (43, UBP304) demonstrated high potency and selectivity toward native GLUK5-containing kainate receptors (KD 0.105 ± 0.007 μM vs kainate on native GLUK5; KD 71.4 ± 8.3 μM vs (S)-5- fluorowillardiine on native AMPA receptors). On recombinant human GLU K5, GLUK5/GLUK6, and GLUK5/GLU K2, KB values of 0.12 ± 0.03, 0.12 ± 0.01, and 0.18 ± 0.02 μM, respectively, were obtained for 43. However, 43 displayed no activity on homomeric GLUK6 or GLUK7 kainate receptors or homomeric GLUA1-4 AMPA receptors (IC50 values > 100 μM). Thus, 43 is a potent and selective GLUK5 receptor antagonist.
Synthesis and characterization of water-soluble phenylene-vinylene-based singlet oxygen sensitizers for two-photon excitation
Nielsen, Christian B.,Johnsen, Mette,Arnbjerg, Jacob,Pittelkow, Michael,McIlroy, Sean P.,Ogilby, Peter R.,Jorgensen, Mikkel
, p. 7065 - 7079 (2007/10/03)
The synthesis and characterization of water-soluble singlet oxygen sensitizers with a phenylene-vinylene motif is presented. The principal motivation for this study was to better understand specific features of a water-soluble molecule that influence the photosensitized production of singlet oxygen upon nonlinear, two-photon excitation of that molecule. To achieve water solubility, sensitizers were synthesized with ionic as well as nonionic substituents. In the ionic approach, salts of N-methylated pyridine, benzothiazole, and 1-methyl-piperazine moieties were used, as were aryl-substituted sulfonic acid moieties. In the nonionic approach, aryl-substituted triethylene glycol moieties were used. Selected photophysical properties of the compounds synthesized were determined, including singlet oxygen quantum yields. Of the molecules examined, the most efficient singlet oxygen sensitizers had triethylene glycol units as the functional group that imparted water solubility. Molecules containing the ionic moieties did not make singlet oxygen in appreciable yield nor did they efficiently fluoresce. Rather, for these latter molecules, rapid charge-transfer-mediated nonradiative processes appear to dominate excited state deactivation.
