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231.
Andreas Jaekel Pascal Lill Stephen Whitelam Barbara Sacc 《Molecules (Basel, Switzerland)》2020,25(23)
Since the pioneering work of Ned Seeman in the early 1980s, the use of the DNA molecule as a construction material experienced a rapid growth and led to the establishment of a new field of science, nowadays called structural DNA nanotechnology. Here, the self-recognition properties of DNA are employed to build micrometer-large molecular objects with nanometer-sized features, thus bridging the nano- to the microscopic world in a programmable fashion. Distinct design strategies and experimental procedures have been developed over the years, enabling the realization of extremely sophisticated structures with a level of control that approaches that of natural macromolecular assemblies. Nevertheless, our understanding of the building process, i.e., what defines the route that goes from the initial mixture of DNA strands to the final intertwined superstructure, is, in some cases, still limited. In this review, we describe the main structural and energetic features of DNA nanoconstructs, from the simple Holliday junction to more complicated DNA architectures, and present the theoretical frameworks that have been formulated until now to explain their self-assembly. Deeper insights into the underlying principles of DNA self-assembly may certainly help us to overcome current experimental challenges and foster the development of original strategies inspired to dissipative and evolutive assembly processes occurring in nature. 相似文献
232.
Cunin F Favier F Pascal JL 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(13):2869-2875
Raman and infrared analysis of the new compounds: ReO3(ClO4), an ivory-white solid, and (ClO2)xReO3(ClO4)1+x (x < or = 1), an orange-red chloryl salt, showed that bridging bidentate [ClO4] and terminal ReO3 groups are present in both complexes. Vibrational data on [ClO4] in ReO3(ClO4) were compared to those obtained experimentally and by DFT calculation on a bridging bidentate [ClO4] in Sb2Cl6(O)(OH)(ClO4). 相似文献
233.
The stability of oil-in-water emulsions prepared using dextran, a natural polysaccharide, hydrophobically substituted with phenoxy groups, was studied. The evolution of the emulsion droplet size was investigated as a function of polymer concentration (Cp=0.2 to 1% w/w in a water phase) and the degree of phenoxy substitution (tau=4.2 to 15.7%). For the highest tau values, emulsions, which presented submicrometer droplets, were stable over more than 4 months at room temperature. The most substituted polymers clearly showed a better efficiency to lower the surface tension at the oil/water interface. DexP did not induce real viscosification of the continuous phase. The linearity of the particle volume variation with time, and the invariability of the volume distribution function, proved that Ostwald ripening was the main destabilization mechanism of the phenoxy dextran emulsions. The nature of the oil dispersed phase drastically affected the behavior of emulsions. While the emulsions prepared with n-dodecane presented a particle growth with time, only few size variations occurred when n-hexadecane was used. Furthermore, small ratios of n-hexadecane in n-dodecane phase reduced the particle growth due to the lower solubility and lower diffusion coefficient in water of n-hexadecane, which acted as a ripening inhibitor. 相似文献
234.
What is the mechanism of oriented crystal growth on rubbed polymer substrates? Topography vs epitaxy
Damman P Coppée S Geskin VM Lazzaroni R 《Journal of the American Chemical Society》2002,124(51):15166-15167
From the oriented growth of p-nitroaniline crystals on various rubbed polymer substrates, the orientation mechanism was found to basically rely upon the formation of intermolecular interactions at the crystal/polymer interface. The observations also show that the surface topography only plays a minor role in the oriented nucleation. 相似文献
235.
Chloride‐Selective Electrodes Based on “Two‐Wall” Aryl‐Extended Calix[4]Pyrroles: Combining Hydrogen Bonds and Anion–π Interactions to Achieve Optimum Performance 下载免费PDF全文
Jad Sabek Dr. Louis Adriaenssens Tomàs Guinovart Dr. Enrique J. Parra Prof. F. Xavier Rius Prof. Pablo Ballester Dr. Pascal Blondeau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):448-454
The performance of chloride‐selective electrodes based on “two‐wall” aryl‐extended calix[4]pyrroles and multiwall carbon nanotubes is presented. The calix[4]pyrrole receptors bear two phenyl groups at opposite meso‐positions. When the meso‐phenyl groups are decorated with strong electron‐withdrawing substituents, attractive anion–π interactions may exist between the receptor’s aromatic walls and the sandwiched anion. These anion–π interactions are shown to significantly affect the selectivity of the electrodes. Calix[4]pyrrole, bearing a p‐nitro withdrawing group on each of the meso‐phenyl rings, afforded sensors that display anti‐Hofmeister behavior against the lipophilic salicylate and nitrate anions. Based on the experimental data, a series of principles that help in predicting the suitability of synthetic receptors for use as anion‐specific ionophores is discussed. Finally, the sensors deliver excellent results in the direct detection of chloride in bodily fluids. 相似文献
236.
Dipl.‐Chem. Christian Schöttle Dr. Pascal Bockstaller Dr. Radian Popescu Prof. Dr. Dagmar Gerthsen Prof. Dr. Claus Feldmann 《Angewandte Chemie (International ed. in English)》2015,54(34):9866-9870
Mo0, W0, Fe0, Ru0, Re0, and Zn0 nanoparticles—essentially base metals—are prepared as a general strategy by a sodium naphthalenide ([NaNaph])‐driven reduction of simple metal chlorides in ethers (1,2‐dimethoxyethane (DME), tetrahydrofuran (THF)). All the nanoparticles have diameters ≤10 nm, and they can be obtained either as powder samples or long‐term stable suspensions. Direct follow‐up reactions (e.g., Mo0+S8, FeCl3+AsCl3, ReCl5+MoCl5), moreover, allow the preparation of MoS2, FeAs2, or Re4Mo nanoparticles of similar size as the pristine metals (≤10 nm). 相似文献
237.
Morvan J Saluden M Agasse V Barbot F Cardinael P Bouillon JP Decock G 《Analytical and bioanalytical chemistry》2006,384(6):1409-1415
Bachus et al. [1] recently described a new derivatisation method using 2-furoyl chloride for the characterisation of mixtures of polyethoxylated
alcohols and their corresponding sulfates. This paper deals with the control of the derivatisation steps; hydrolysis and extraction
conditions were optimised. The method is extended to the characterisation of alkyl sulfosuccinates, alkyl sulfoacetates and
alkyl phosphates and to the analysis of residual polyethoxylated alcohols in surfactants. Extraction of non-ionic compounds
using solid-phase extraction cartridges was performed before derivatisation. Residual amounts of alcohol were determined in
five commercial anionic surfactants. Moreover, direct derivatisation without preliminary SPE in the same anionic surfactants
proved to be efficient for dry samples. 相似文献
238.
A new linker cis-5-aminopent-3-enoic acid (cis-Apa) was prepared for the synthesis of cyclic pseudopeptides by cyclization-cleavage by using ring-closing methatesis (RCM). We developed a new synthetic pathway for the preparation of the cis-Apa linker that was tested in the cyclization-cleavage process of different RGD peptide sequences. Different macrocyclic peptidomimetics were prepared by using this integrated microwave-assisted method, showing that the readily available cis-Apa amino acid is well adapted as a linker in the cyclization-cleavage process. 相似文献
239.
Bisson J Poupard P Pawlus AD Pons A Darriet P Mérillon JM Waffo-Téguo P 《Journal of chromatography. A》2011,1218(36):6079-6084
The phytochemical study of the root extract of the stilbenoid-rich Vitis riparia × Vitis berlandieri grapevine was carried out by centrifugal partition chromatography (CPC). For this reason, we developed a new elution mode we named back-step, which allowed us to obtain cleaner fractions and a more efficient separation process when used in conjunction with a classical elution approach. Three hydroxystilbenes: (E)-resveratrol, (E)-?-viniferin and (E)-vitisin C, with greater than 90% purity were thus obtained through such process, with minimal sample handling and purification steps. Online coupling of CPC to ESI mass spectrometry was used for optimization of the separation parameters and to facilitate the characterization of the stilbenoids. This study details the first phytochemical investigation of stilbenoids from the hybrid species together with a new elution mode able to widen the range of ARIZONA biphasic systems. 相似文献
240.
Michael H��lsen Michael Dolg Pascal Link Uwe Ruschewitz 《Theoretical chemistry accounts》2011,129(3-5):367-379
Improved energy-optimized (6s5p4d) and (7s6p5d) primitive valence basis sets have been derived for energy-consistent scalar-relativistic 4f-in-core pseudopotentials of the Stuttgart-Cologne variety modeling divalent lanthanides with a $4\hbox{f}^{n+1}$ occupation (n = 0?C13 for La?CYb). Segmented contracted basis sets covering the range of polarized double-, triple-, and quadruple-zeta quality, augmented by 2f1g correlation sets, were created for use in molecular calculations. The basis sets contain smaller (4s4p3d) and (5s5p4d) primitive subsets, which are designed in particular for solid state calculations of crystals containing divalent lanthanide ions. Hartree?CFock, density functional theory and coupled cluster results obtained with the new basis sets for lanthanide atomic ionization potentials as well as of geometry optimizations of various test molecules, i.e. selected lanthanide mono- and dihydrides, mono- and difluorides, and monooxides, show a satisfactory agreement with experimental data as well as with corresponding scalar-relativistic all-electron results. Core-polarization potentials are found to improve the results, especially for the atomic first and second ionization potentials. 相似文献