Search results for "donor"
showing 10 items of 436 documents
Controlled Self-Assembly of Electron Donor Nanotubes
2009
We employ a combination of urea-urea hydrogen bonds and pi-pi stacking interactions to obtain soluble self-assembled nanotubes decorated with electron-donor TTF derivatives on the periphery. We have investigated the structure and stability of the nanotubes with a combination of experiments and high-level DFT calculations. We also demonstrate that the association process can be controlled by changes in the hydrogen-bonding ability of the solvent and electrochemically.
Recurrence of hepatocellular carcinoma after liver transplantation: an update.
2015
Liver transplantation is the only curative alternative for selected patients with hepatocellular carcinoma (HCC) who are not eligible for resection and/or with decompensated cirrhosis. According to Milan criteria the 5-year survival rate is 70–85%, with a recurrence-free survival of 75%. However, HCC recurrence rate after liver transplantation remains a significant problem in the clinical practice. The prognosis in patients with HCC recurrence is poor. The treatment of choice for HCC recurrence is surgery, but it seems that a systemic treatment based on combination of an mTOR inhibitor with sorafenib can be used. Data on safety and efficacy are limited, clinical monitoring is necessary. Th…
Oligo(2,5-thienyleneethynylene)s with Terminal Donor-Acceptor Substitution
2006
Five oligo(2,5-thienyleneethynylene) series (OTE, n = 1–5), namely the push-pull substituted compounds 1b-5b and 1c-5c, the purely donor substituted compounds 1a-5a and two precursor series with protected and deprotected ethynyl end-groups, respectively, were obtained by a convergent synthetic strategy. The extension of the conjugated chromophores in the donor-acceptor OTE (DAOTE) series is superimposed by an intramolecular charge transfer (ICT), which decreases with an increasing number, n, of repeat units. The overall effect is studied by the convergence of the UV/Vis absorption maxima λmax (n) → λ∞ for n → ∞.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Mono-, di- and tri-nuclear Ni(II) complexes of N-, O-donor ligands: structural diversity and reactivity
2002
A series of mono-, di- and tri-nuclear Ni(II) complexes of N, O-donating molecules possessing ---H2C---NH--- and ---HC=N--- moieties have been synthesized and characterized and the structures have been determined by single crystal X-ray diffraction. All these exhibited interesting molecular packing in their crystal lattices. Di-nuclear complexes were found to be cleaved in pyridine to result in mononuclear ones with additional coordinations being provided by pyridine. Di-nuclear complexes were found to form urea adducts as demonstrated based on absorption and vibrational studies.
Long-range substituent and temperature effect on prototropic tautomerism in 2-(acylmethyl)quinolines
2001
Tautomeric equilibria between 2-(cinnamoylmethyl)quinoline, (Z)-1,2-dihydro-2-(cinnamoylmethylene)quinoline and (Z)-4-phenyl-1-(2-quinolyl)-1,3-butadien-2-ol were studied by 1H, 13C and 15N NMR methods. The —CHCH— fragment conjugated with phenyl and a strong electron donor p-(1-pyrrolidine) substituent were found to favour the enolimine tautomer. This undergoes fast exchange (on the NMR time-scale) with the enaminone form. The amount of the latter tautomer was found to increase at low temperatures. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of the first imidazolyl-triphosphines containing a Triphos unit
2007
Abstract Since biphasic liquid–liquid continuous-flow catalytic processes often require the use of cationic phosphine ligands for the metal sequestration in the polar phase, we have prepared the first imidazolyl triphosphines, named Triphosim and Triphosmim. These ligands contain the Triphos unit [-P(CH2CH2PPh2)] which is linked to the imidazole fragment and have been obtained in three steps from imidazole (or 2-methylimidazole), diethylvinylphosphonate and diphenylvinylphosphine with global yields of 42–48%. The Triphosim ligand adopts a tridentate P-coordination mode in a palladium dichloride complex and the reaction of the dangling imidazole function with alkyl halides leads to a new kin…
Icosahedral carboranes as scaffolds for congested regioselective polyaryl compounds: the distinct distance tuning of C–C and its antipodal B–B
2019
Four-fold aryl substituted o-carborane derivatives with defined patterns of substitution at the antipodal region of the cluster carbon atoms have been achieved. It is proven that this region is congested but lacks steric hindrance. Also, the two antipodal sites Cc–Cc and B9–B12 are affected very distinctly by electron donor substituents.
α-d-Glucopyranose Adsorption on a Pd30 Cluster Supported on Boron Nitride Nanotube
2016
Boron nitride nanotube (BNNT) as an innovative support for carbohydrate transformation processes was evaluated, using density functional theory. The α-d-glucopyranose adsorption on a Pd30 cluster, supported on BNNT, was used to check both the local activity of topologically different metallic sites and the effects of the proximity of the BNNT surface to the same metallic sites. Detailed geometrical and electronic analyses performed on Pd30/BNNT and α-d-glucopyranose/Pd30/BNNT systems were discussed. It was observed that the deposition of the Pd30 cluster onto the BNNT support gives rise to an electronic rearrangement, determining a charge transfer from the support to the adsorbed metal clus…
Vacancy Defects in Ga2O3: First-Principles Calculations of Electronic Structure
2021
This research was funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP08856540) as well as by the Latvian research council via the Latvian National Research Program under the topic ?High-Energy Physics and Accelerator Technologies?, Agreement No: VPP-IZM-CERN-2020/1-0002 for A.I. Popov. In addition, J. Purans is grateful to the ERAF project 1.1.1.1/20/A/057 while A. Platonenko was supported by Latvian Research Council No. LZP-2018/1-0214. The authors thank A. Lushchik and M. Lushchik for many useful discussions. The research was (partly) performed in the Institute of Solid State Physics, University of Latvia ISSP UL. ISSP UL as…
Effect of transition metals and homogeneous hydrogen producers in the hydrothermal liquefaction of sewage sludge
2022
Hydrothermal liquefaction (HTL) of sewage sludge (SS) was performed in the presence of metallic Zn, Fe and Ni to investigate their effect on the performances of the process in terms of product yields and quality. Experiments were performed in subcritical water at 350 ◦C for 10 min using each metal individually and in the presence of homogenous hydrogen producers like formic acid (FA) and KOH. Interesting results were obtained with Zn that when used alone or in the presence of KOH, increased the cumulative biocrude (BC) yields and resulted in energy recoveries (ER) higher than 100% with respect to initial energy content of the biomass, thus indicating that HTL of SS is globally endothermic. …