Search results for "Ologen"
showing 10 items of 31 documents
Flexible vs Rigid Networks of Two Isoreticular Viologen-Carboxylate based PCPs: the Ligand Size Effect
2018
International audience
Probing the Folding of Peptide–Polymer Conjugates Using the π-Dimerization of Viologen End-Groups
2020
The synthesis of a foldable viologen-functionalized peptide–polymer conjugate is presented. The ABA-type triblock conjugate with a PEG polymer was capped with a FHFHF pentapeptide sequence and further modified with a viologen building block at both chain ends. The pH-responsive peptide domains fold into an intermediate structure inducing close proximity of the viologen units, which upon a reduction step form π-dimers of the radical cation. Overall the intramolecular folding and intermolecular self-assembly process leads to the formation of supramolecular nanorods. Mixing of viologen-peptide–polymer conjugates with unfunctionalized conjugates leads to crosslinking of the nanorods and hydroge…
Sicurezza ed Efficacia dell’inserto Ologen™ nella chirurgia del glaucoma: risultati preliminari di uno studio prospettico di fase II
2009
The Recognition of Viologen Derivatives in Water by N-Alkyl Ammonium Resorcinarene Chlorides
2017
Three water-soluble N-alkyl ammonium resorcinarene chlorides decorated with terminal hydroxyl groups at the lower rims were synthesized and characterized. The receptors were decorated at the upper rim with either terminal hydroxyl, rigid cyclohexyl, or flexible benzyl groups. The binding affinities of these receptors toward three viologen derivatives, two of which possess an acetylmethyl group attached to one of the pyridine nitrogens, in water were investigated via 1H NMR spectroscopy, fluorescence spectroscopy, and isothermal titration calorimetry (ITC). ITC quantification of the binding process gave association constants of up to 103 M-1. Analyses reveal a spontaneous binding process whi…
Ionic liquid crystals based on viologen dimers: tuning the mesomorphism by varying the conformational freedom of the ionic layer
2016
ABSTRACTWe investigated the liquid crystal behaviour of newly synthesised bistriflimide salts of symmetric viologen dimers. A smectic A phase was observed for intermediate spacer lengths and for relatively long lateral alkyl chains. The systems were characterised by thermal analysis, polarised optical microscopy, X-ray scattering and solid-state NMR. An intermediate ordered smectic phase was also exhibited by the compounds (except for systems with very short lateral chains) consisting of molten layers of alkyl chains and partially ordered ionic layers. These results, relating to the mesomorphic behaviour of viologen salts, are qualitatively compared to those of the more common imidazolium s…
A robust viologen and Mn-based porous coordination polymer with two types of Lewis acid sites providing high affinity for H 2 O, CO 2 and NH 3
2017
A novel porous coordination polymer [Mn(pc3)(H2O)2]·xH2O (3 < x < 4) is synthesized in water at pH = 7 using the anionic viologen-carboxylate ligand 4,4′-bipyridinium,1,1′-bis-(2,4-dicarboxyphenyl) (pc32−). Dehydration of the material results in the formation of open pores containing two types of accessible Lewis acid sites: exposed Mn2+ cations and N+ atoms of viologen units. Due to this property the PCP shows high affinity and capacity in the adsorption of H2O, CO2 and NH3. Despite the presence of strong adsorption sites this material is stable in liquid water and in gaseous NH3.
Structure and properties of zwitterionic polysoaps: functionalization by redox-switchable moieties
2007
Redoxactive monomeric and polymeric surfactants containing viologen and N-alkylated nicotinic acid moieties were synthesized. These systems are potentially able to trigger reversible changes of self-organization by creation or removal of a charge via a redox reaction. Hence, they are investigated with respect to solubility, aggregation behavior, and their electrochemical properties in water. — All monomers, but only the viologen polymers are water-soluble and drastically decrease the surface tension of water. Critical micelle concentrations are observed for the monomers only. — The chemical reversibility of the redox reactions of the compounds in water was investigated using cyclic voltamme…
Evoluzione degli adiuvanti nella trabeculectomia: risultati di uno studio randomizzato su un inserto di collagene biodegradabile versus mitomicina C.
2011
Photoinduced Electron Transfer Reactions in a Porphyrin−Viologen Complex: Observation of S2 to S1 Relaxation and Electron Transfer from the S2 State
1999
Photoinduced Energy Transfer Reactions in a Porphyrin-Viologen Complex: Observation of S2 to S1 Relaxation and Electron Transfer from the S2 state
Viologen-based ionic liquid crystals: induction of a smectic A phase by dimerisation.
2014
The stability of thermotropic ionic liquid crystals is essentially due to micro-phase segregation between the ionic heads and the long alkyl chains. Here we show, using newly synthesized viologen dimers, that the structure of the central core is another key parameter to play with in order to tune the mesomorphic behaviour. © 2014 the Owner Societies.