Search results for "cyanate"
showing 10 items of 210 documents
Pseudohalide derivatives of manganese(II) and copper(II) complexes with mepirizole, a biologically active pyrimidyl-pyrazole ligand
1989
Abstract The synthesis and characterization of thiocyanate and azide derivatives of mepirizole(4-methoxy-2-(5-methoxy-3-methyl-pyrazol-1-yl)-6-methylpyrimidine, hereinafter L) with manganese(II) and copper(II) is reported. The compounds were characterized by IR, electronic and EPR spectra and analytical data. Spectroscopic results suggest the existence of dimeric neutral entities [L2Cu2(μ-X)2(X)2] (X = NCS or N3) with unsymmetrical end-to-end bridges and five-coordination geometry around the copper(II) ion. Magnetic susceptibility data show that in the azide derivative the copper atoms are antiferromagnetically coupled (J = −18 cm−1), but no magnetic exchange interaction could be detected i…
A study of electron transfer in Ru(dcbpy)2(NCS)2 sensitized nanocrystalline TiO2 and SnO2 films induced by red-wing excitation.
2008
Excited state dynamics and electron transfer from the Ru(dcbpy)2(NCS)2 (RuN3) sensitizer to semiconductor nanoparticles were studied using time-resolved femtosecond absorption spectroscopy. We found that excitation of the red wing of the absorption spectrum of the sensitizer populates the (3)MLCT state directly, both in solution and attached on semiconductor nanoparticle films. Electron injection is slowed down and becomes gradually less efficient as excitation moves towards red from the absorption maximum at 535 nm. At 675 nm the injection is non-exponential and characterized by 5, 30 and 180 ps time constants. The non-exponential electron injection observed is assigned to injection from a…
Fluctuation Methods To Study Protein Aggregation in Live Cells: Concanavalin A Oligomers Formation
2011
Prefibrillar oligomers of proteins are suspected to be the primary pathogenic agents in several neurodegenerative diseases. A key approach for elucidating the pathogenic mechanisms is to probe the existence of oligomers directly in living cells. In this work, we were able to monitor the process of aggregation of Concanavalin A in live cells. We used number and brightness analysis, two-color cross number and brightness analysis, and Raster image correlation spectroscopy to obtain the number of molecules, aggregation state, and diffusion coefficient as a function of time and cell location. We observed that binding of Concanavalin A to the membrane and the formation of small aggregates paralle…
Isobaric vapor-liquid equilibria for extractive distillation of 1-propanol + water mixture using thiocyanate-based ionic liquids
2017
Abstract This paper presents vapor-liquid equilibrium (VLE) data at 101.3 kPa for the ternary systems 1-propanol + water + 1-ethyl-3-methylimidazolium thiocyanate [emim][SCN] and 1-propanol + water + 1-butyl-3-methylimidazolium thiocyanate [bmim][SCN] and their constituents binary systems. The experimental data obtained were correlated using the NRTL, eNRTL and UNIQUAC models. It was found that the addition of these ionic liquids enhance the relative volatility of 1-propanol to water, and the separation ability follows the order of [emim][SCN] > [bmim][SCN]. The results obtained were compared with the VLE data of the system containing this azeotropic mixtures with different imidazolium-base…
Cell adhesion on UV-crosslinked polyurethane gels with adjustable mechanical strength and thermoresponsiveness
2021
Temperature-responsive polyurethane (PU) hydrogels represent a versatile material platform for modern tissue engineering and biomedical applications. However, besides intrinsic advantages such as high mechanical strength and a hydrolysable backbone composition, plain PU materials are generally lacking bio-adhesive properties. To overcome this shortcoming, the authors focus on the synthesis of thermoresponsive PU hydrogels with variable mechanical and cell adhesive properties obtained from linear precursor PUs based on poly(ethylene glycol)s (pEG) with different molar masses, isophorone diisocyanate, and a dimerizable dimethylmaleimide (DMMI)-diol. The cloud point temperatures of the dilute,…
4-(2-Adamantyl)thiosemicarbazone
1984
Aus der Umsetzung von 4-(2-Adamantyl)thiosemicarbazid (1) mit den Carbonylverbindungen 2a-d gehen die 4-(2-Adamantyl)thiosemicarbazone 3a-d hervor. Die Startkomponente 1 ist aus 2-Aminoadamantan (4) uber das (2-Adamantyl)-isothiocyanat (5) zuganglich. Verbindung 5 und Vertreter des Strukturtyps 3 vermogen antivirale, antimykotische und antipyretische Wirkung auszuuben. Antiviral Agents, XXIV: 4-(2-Adamantyl)thiosemicarbazones Reactions of 4-(2-adamantyl)thiosemicarbazide (1) with the carbonyl compounds 2a-d yield the 4-(2-adamantyl)thiosemicarbazones 3a-d. The starting material 1 is accessible from 2-aminoadamantane (4) via 2-adamantyl isothiocyanate (5). Compound 5 and representatives of t…
Regio- and stereoselective synthesis of constrained enantiomeric β-amino acid derivatives
2008
Abstract Chlorosulfonyl isocyanate addition to (−)- and (+)-apopinene furnished monoterpene-fused β-lactams in highly regio- and stereospecific reactions. β-Lactams 5 and 13 exhibited reactivities similar to those of the cycloalkane-fused analogs and were easily converted to the β-amino acid and its protected derivatives. The base-catalyzed isomerization of the cis -amino ester afforded the corresponding trans -amino acid enantiomers in excellent yields. The complete isomerization is explained by the stability difference, which was estimated by ab initio calculations between the cis- and trans -diastereomers.
Structural and magnetic studies of tetranuclear heterometallic M/Cr (M = Co, Mn) complexes self-assembled from zerovalent cobalt or manganese, Reinec…
2010
Abstract Four novel heterometallic complexes [Co2Cr2(NCS)4(HDea)2(Dea)2]·4dmf (1), [Co2Cr2(NCS)4(HDea)2(Dea)2]·4dmso (2), [Mn2Cr2(NCS)4(HDea)2(Dea)2(dmf)2]·2dmf (3) and [Mn2Cr2(NCS)4(HDea)2(Dea)2(dmso)2]·4dmso (4) have been prepared using zerovalent cobalt (1, 2) or manganese (3, 4), Reineckes salt, ammonium thiocyanate and a non-aqueous solution of diethanolamine (H2Dea) in air. The single X-ray analysis reveals that all compounds have similar centrosymmetric crystal structures based on a tetranuclear {M2Cr2(μ3-O)2(μ-O)4} (M = Co, Mn) core. Variable-temperature magnetic susceptibility measurements of 1, 2 and 4 show antiferromagnetic coupling between the magnetic centers, while 3 exhibits …
Covalently attached polymer mono- and multilayers on silanized glass substrates
1996
Abstract Applying grazing incidence FTIR and ellipsometry, the reaction of poly [(1-methyl-vinyl isocyanate)-alt-(maleic anhydride)](IAP) with amino-silanized glass and silicon oxide surfaces has been investigated. A reactive surface containing isocyanate and anhydride groups was formed after the adsorption of the polymer. The layer could be further functionalized using 2-aminoethanol. Multilayers could be built up by adsorbing a second layer of IAP onto an already reacted first layer of IAP.
Transparent thermoplastic polyurethanes based on aliphatic diisocyanates and polycarbonate diol
2016
Segmented thermoplastic polyurethanes (PUs) were synthetized using polycarbonate diol as soft segment with a molar mass of 500 and as a hard segment 1,5-pentanediol with a combination of isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI). Differential scanning calorimetry, differential mechanical analysis, Fourier transform infrared-attenuated total reflection spectroscopy, haze, transmittance, hardness, tensile properties and retention of tensile properties tests were employed to characterize the different PUs. The results of this study show that IPDI/HDI relation has a significant impact on the phase mixing, crystallinity and therefore on the PU’s properties. The variati…