Supramolecular Science最新文献

Three novel amphiphilic phenylazonaphthalenes, namely, 6-(4-(4-octylphenylazo)naphthoxy)hexanoic acid, 6-(4-(4-dodecylphenylazo)naphthoxy)hexanoic acid, 6-(4-(4-hexadecylphenylazo)naphthoxy)hexanoic acid, were synthesized by diazo coupling, etherification and hydrolysis reactions successively. The kinetic studies of the trans–cis isomerization indicated that about 95% of the trans isomers of these compounds in chloroform solutions were transformed to cis isomers under the irradiation of near-ultraviolet light (380±30 nm) observed from UV–Vis spectra. In the dark condition, the cis isomers could reversibly convert to trans isomers following the first-order kinetics at the rates of 4.9×10^-4, 5.7×10^-4, 7.7×10^-4 S^-1, respectively.

The system of real-time evolution and analysis of films’ parameters has been suggested and developed. Its principle is based on surface plasmon resonance. The results of Ag film left in air have been obtained by this system.

Using a needle-circle electrode configuration, we investigated the relationship between morphologies of polypyrrole (PPy) and polymerization conditions, such as the kinds of electrolyte, solvent and electrode, the concentrations of electrolyte and monomer, the applied voltages, etc. The various morphologies of PPy are classified into seven types. The influence of the substrate was also taken into account. Four types of morphologies of PPy under the mica are shown. We recently obtained organized PPy particles by the induction of the mica substrate. The neuron network-like interconnections of PPy fabricated by controlling the polymerization conditions are shown.

We have synthesized a squarylium dye based on 2,6-di-tert-butylpyrylium (full name given in the text). Its nonlinear optical properties was detected by the hyper-Rayleigh light scattering technique in a chloroform solution, although this type of chromophore has a symmetrical structure and a negligible permanent dipole moment. The internal reference method was employed to determine the first hyperpolarizability β value of the chromophore and further discussion is provided.

In this paper, we alternately deposit transition metal Cd²⁺ neutralized polyelectrolytes and ligands pyridine contained polymer via the formation of complexes, and by sequential reaction with H₂S gas, in situ fabricate CdS nanoparticles/polymer heterostructured film. The driving force for the construction of multilayered films is based on covalent coordination.

Self-aggregation of light active barbituric acid derivatives and their self-assembly with melamine derivatives through hydrogen-bonding, π-aromatic stacking, and other weak interactions were studied by UV–visible absorption and fluorescence spectroscopy. PB₁₂Me has the same fluorescence behavior as PB₁₂ in chloroform though it cannot aggregate through a hydrogen-bond. AB₁₂ and AB₁ lead to different degrees of fluorescence splitting. When barbituric acid molecular components were self-assembled with melamine a similar splitting phenomenon was observed. It was shown that π-aromatic stacking resulted in the exclusive fluorescence changes and H-aggregates were formed in solution.

In the last decade, molecular electronics, as an active frontier of interdisciplinary research areas, has become one of the most rapidly developing fields, and attracted worldwide interests. The fundamental element of molecular electronics is a molecular device or a supramolecular device, which is an organized molecular system constructed mainly by organic molecules or biomolecules that have some specific functions in signal detection, process, storage, and transmission through chemical or physical interactions at molecular or supramolecular levels. A molecular device (MD) can involve chemical information processes, and be relatively easy to realize a large number of links between the molecules. The links can be controlled by the external signals. These are the expected features of molecular computing and directly involve chemical and biological processes. MD may overcome some limitations of the solid-state chips, and can be directly applied to chemical and biological processes. Molecular electronics is a part of bioelectronics. It will play an important and revolutionary role in the next century. This paper intends to review the research activities of molecular electronics in China, particularly in LMBE.

Liquid crystal (LC) alignment techniques based on various kinds of ultrathin organized molecular films are reviewed. The mechanisms of LC alignment on the organized films are discussed. For the homeotropic alignment of LCs the main anchoring mechanism is due to the dipole–dipole interaction between polar groups of an aligning agent and LC molecules while the homogeneous alignment is mainly attributed to the orientation of polymer chains or polymer aggregates. An experimental system for an anchoring transition induced by a conformation change of aligning molecules is introduced. Finally the AFM experimental observations on the rubbed polymer films and its mechanisms are summarized.

Optoelectric properties of a novel liquid crystal zinc tetraphenyltetrabenzoporphyrin (ZnTPTBP) is studied with the aid of surface photovoltaic spectroscopy (SPS) and electric-field-induced SPS. The surface photovoltage response at 550 nm under external field is assigned to the $\text{π–π}{}^{\mathrm{\ast }}$ transmission in the columns of micro π system formed in ZnTPTBP solid film and is thought to be related with the electro-optical memory effect of liquid crystal porphyrin.