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71.
Focante F Camurati I Resconi L Guidotti S Beringhelli T D'Alfonso G Donghi D Maggioni D Mercandelli P Sironi A 《Inorganic chemistry》2006,45(4):1683-1692
Reaction between 7-azaindole and B(C6F5)3 quantitatively yields 7-(C6F5)3B-7-azaindole (4), in which B(C6F5)3 coordinates to the pyridine nitrogen of 7-azaindole, leaving the pyrrole ring unreacted even in the presence of a second equivalent of B(C6F5)3. Reaction of 7-azaindole with H2O-B(C6F5)3 initially produces [7-azaindolium]+[HOB(C6F5)3]- (5) which slowly converts to 4 releasing a H2O molecule. Pyridine removes the borane from the known complexes (C6F5)3B-pyrrole (1) and (C6F5)3B-indole (2), with formation of free pyrrole or indole, giving the more stable adduct (C6F5)3B-pyridine (3). The competition between pyridine and 7-azaindole for the coordination with B(C6F5)3 again yields 3. The molecular structures of compounds 4 and 5 have been determined both in the solid state and in solution and compared to the structures of other (C6F5)3B-N-heterocycle complexes. Two dynamic processes have been found in compound 4. Their activation parameters (DeltaH = 66 (3) kJ/mol, DeltaS = -18 (10) J/mol K and DeltaH = 76 (5) kJ/mol, DeltaS = -5 (18) J/mol K) are comparable with those of other (C6F5)3B-based adducts. The nature of the intramolecular interactions that result in such energetic barriers is discussed. 相似文献
72.
Youssry M Coppola L Nicotera I Ar G Schmidt C 《Journal of colloid and interface science》2011,358(2):506-512
The influence of shear flow on bilayer structures (vesicle and planar lamellar phases, L(α)), formed in DDAB/lecithin ternary systems, is studied by means of conventional rheology, Rheo NMR, and optical microscopy. The vesicles in the diluted (Lam(1)) phase are polydisperse multilamellae which turn into smaller monodisperse vesicles under shear. The concentrated (Lam(2)) phase is formed by non-oriented lamellae that do not surprisingly exhibit any pronounced shear-induced alignment prior to the transition into giant multilamellar vesicles. The biphasic region (Lam(1)+Lam(2)) shows a mosaic texture with a powder pattern indicating the prevalence of lamellae that transform into onions under shear. 相似文献
73.
74.
The palladium-catalyzed electrocarbonylation of heteroaromatic iodides, performed in the presence of formic acid under one atmosphere of carbon monoxide, affords heteroaromatic aldehydes in moderate to good yields. It has been developed a new application of palladium-catalyzed formylation using carbon monoxide, formic acid and tertiary amines as ligands under electrochemical reducing conditions. 相似文献
75.
Yevheniia Velihina Thomas Scattolin Denys Bondar Stepan Pil'o Nataliya Obernikhina Olesksiy Kachkovskyi Ivan Semenyuta Isabella Caligiuri Flavio Rizzolio Volodymyr Brovarets Yevgen Karpichev Steven P. Nolan 《Helvetica chimica acta》2020,103(12):e2000169
New potential bioactive oxazolopyrimidines have been synthesized using two main approaches: the pyrimidine ring annulation on a functionalized oxazole and the benzoyl bromide trimerization followed by rearrangement and formation of the oxazolo[5,4-d]pyrimidine scaffold. The docking analyzes have shown that 7-piperazine substituted oxazolo[4,5-d]pyrimidines 8a – 8c could be potential VEGFR2 inhibitors with high free energy of ligand–protein complex formation (ΔG: −10.1, −9.6, −9.8 kcal/mol, respectively). In vitro antitumor assays confirmed theoretical predictions that oxazolo[4,5-d]pyrimidines 8a – 8c containing positively charged piperazine moiety should demonstrate significantly higher cytotoxic effects. 4-[5-(4-Chlorophenyl)-2-phenyl[1,3]oxazolo[4,5-d]pyrimidin-7-yl]piperazin-1-ium trifluoroacetate ( 8c ) exhibited a slightly higher antiproliferative effect (IC50=0.21 μm ) than doxorubicin (IC50=0.36 μm ) on MDA-MB-231 cell line and has relatively good results on OVCAR-3 (IC50=1.7 μm ) and HCT-116 (IC50=0.24 μm ) cells. 相似文献
76.
We illustrate recent developments of dynamical meteorology and climate studies that have been approached by means of stochastic differential equations. In particular, we present stochastic dynamics reasoning in climate theory, wave excitation and dynamic initialization of meteorological fields. A few possible future developments are also indicated. 相似文献
77.
Isabella Miglioli Luca Muccioli Silvia Orlandi Matteo Ricci Roberto Berardi Claudio Zannoni 《Theoretical chemistry accounts》2007,118(1):203-210
We set up a model for discotic liquid crystal dimers and study, by means of Monte Carlo simulations, their phase behaviour
and self–assembling properties, in comparison with the simpler monomeric case. Each discotic dimer is described by two oblate
Gay–Berne ellipsoids connected by a flexible spacer, modelled by a harmonic “spring” of three different lengths. We find that
dimerization in general yields produces a significant change on the phase behaviour, with an increase of the columnar–nematic
transition temperature, a widening of the nematic region and the apparent suppression of the crystalline phase in favour of
the columnar phase up to very low temperatures. Longer spacers prove to ease the formation of columns and to increase the
orientational order.
Contribution to the Fernando Bernardi memorial issue. 相似文献
78.
Isabella Villota Paulo C. Calvo Oscar I. Campo Faruk Fonthal 《Molecules (Basel, Switzerland)》2022,27(19)
This article presents microneedles analyses where the design parameters studied included length and inner and outer diameter ranges. A mathematical model was also used to generalize outer and inner diameter ratios in the obtained ranges. Following this, the range of inner and outer diameters was completed by mechanical simulations, ranging from 30 μm to 134 μm as the inner diameter range and 208 μm to 250 μm as the outer diameter range. With these ranges, a mathematical model was made using fourth-order polynomial regressions with a correlation of 0.9993, ensuring a safety factor of four in which von Misses forces of the microneedle are around 17.931 MPa; the ANSYS software was used to analyze the mechanical behavior of the microneedles. In addition, the microneedle concept was made by 3D printing using a bio-compatible resin of class 1. The features presented by the microneedle designed in this study make it a promising option for implementation in a transdermal drug-delivery device. 相似文献
79.
80.
Jan Franz Franco A. Gianturco Isabella Baccarelli 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2014,68(7):1-9
Quantum scattering calculations are presented for the interaction of low energy positrons with the uracil molecule, an important component of biological systems. The rotational elastic and inelastic cross sections and vibrational inelastic cross sections are reported and compared with existing experiments, indicating a general trend of the cross sections different from the experimental findings and in line with what should be expected from the behavior of the total cross sections in similar polar targets. Some specific considerations can be drawn on the reliability of existing experiments, as to their size vis-à-vis to the computed integral cross sections over the same range of energies. 相似文献