Investigation of the distribution of the negative charge in anionic cyanine dyes by means of lanthanide shift reagents

It was established by PMR with lanthanide shift reagents that the charge in anionic cyanine dyes with a linear chromophore is concentrated at the ends of the polymethine chain, while in compounds containing a vinylene group in the chromophore it is concentrated in the region of the five-membered ring. The results are compared with the data from¹³C NMR spectroscopy and relaxation measurements in the presence of Gd(fod)₃. The validity of the conclusions is also considered.Kiev University. Institute of Organic Chemistry, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Teoreticheskaya i Éksperimental'naya, Vol. 27, No. 2, pp. 197–201, March–April, 1991. Original article submitted December 20, 1989.     

Investigation of substituted 2- and 3-thiolene 1,1-dioxides by PMR spectroscopy with the aid of a lanthanide shift reagent

The reaction of lanthanide shift reagent Eu(FOD)₃ with 3-phenyl- and 3- and 4-chloro-2-thiolene 1,1-dioxides and with 3-phenyl-3-thiolene 1,1-dioxide was investigated by PMR spectroscopy. The geometrical structure of the adduct of the lanthanide shift reagent with 4-chloro-2-thiolene 1,1-dioxide was found.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 314–317, March, 1984.     

Diels–Alder Reaction as an Indicator of Internal and External Factors Influencing the Rate and Equilibrium: Kinetics,Thermochemistry, Catalysis,and High Pressure. A Review

Doklady Chemistry - The Diels–Alder reaction (DAR), in addition to its enormous synthetic potential, is the most reliable testing ground for quantitative research of the influence of various...     

Effect of Distributed Suction on the Development of Disturbances on the Wing Profile

Doklady Physics - The results of experimental investigations of the effect of distributed suction through a perforated section of a symmetric wing profile on the spatial development of disturbances...     

Atomic-force microscopy of submicron films of electroactive polymer

Atomic-force microscopy is used to study the supramolecular structure of submicron films of electroactive thermally stable polymer (polydiphenylenephthalide (PDP)). It has been demonstrated that PDP films produced using centrifuging are solid homogeneous films with thicknesses down to several nanometers, which correspond to two or three monomolecular layers. The film volume is structurized at thicknesses greater than 100 nm. The study of the rheological properties of solutions used for film production yields a crossover point that separates the domains of strongly diluted and semidiluted solutions. A transition from the globular structure to the associate structure is observed in films that are produced using solutions with a boundary concentration. A model of the formation of polymer film that involves the presence of associates in the original solution is discussed.     

Supramolecular structure of electroactive polymer thin films

This paper presents the results of an experimental investigation of the supramolecular structure of polydiphenylenephthalide thin films that exhibit effects of resistive switching. The supramolecular structure of the polymer has been investigated using small-angle neutron scattering in conjunction with atomic force microscopy. It has been found that the internal structure of polymer films consists of structural elements in the form of spheroids. The sizes of the structural elements, which were obtained from the neutron scattering data and analysis of the atomic force microscopy images, correlate well with each other. A model of the formation of polymer layers has been proposed. The observed structural elements in polymer films are formed due to the association of macromolecules in the initial polymer solution.     

Emission properties of a silicon-polymer-vacuum planar structure

Self-sustained electron emission from a silicon-polymer planar structure is studied experimentally. It is found that emission can be initiated by a short-term action (e.g., a vacuum microdischarge). The I–V characteristics and time dependence of the emission current are recorded. It is shown that the value and stability of the emission current depend on the thickness of the polymer film. A model explaining the origin of and conditions for self-sustained electron emission is proposed. It is based on today’s concepts of electron emission from insulating layers (Malter effect) with regard to the structure and properties of polymer films.     

A macrocyclic bis-cyanine dye

The bis-indocarbocyanine 1, the first dye of a “sandwich” type with parallel polymethine chains bonded by two ethylene links, is described. Its structure is proved with the help of visible spectra based upon the theory of chromophore interaction.     

In memory of Sergei A. Kornilov

Orbituary

In memory of Sergei A. Kornilov