Thiophene-containing monomers for the synthesis of new polythiopheneferrocenes

Russian Chemical Bulletin - Synthesis of arylenebis(2-aminothiophene-3-carbonitriles) by the Gewald reaction was developed. The structures of the synthesized monomers were established by IR and NMR...     

Investigation of the formation of poly(ethylene terephthalate) with model molecules. III. Metal-catalyzed esterification and alcoholysis reactions: Influence of the structure of the reactants and of the nature of the reaction medium

With a reaction conducted on model molecules with low amounts of catalysts and at low temperatures (170–225°C), it was shown that esterification is mainly catalyzed by the carboxylic acid groups and by the titanium derivatives; the activity of the other metals can only be seen when the concentration in carboxylic acid groups is low. In the alcoholysis reaction, the activity of Zn, Mn, and (much less) Ti, decreases when the percentage of ester in the reaction medium decreases, whereas it is the opposite with Sb. Moreover, Zn, Mn, and Co are sensitive to trace amounts of carboxylic groups (their activity decreases), whereas Ti is much less affected.     

Syntheses and properties of novel non-ionic fluorinated multichains “star-like” surfactants

A series of star-like nonionic surfactants (with two hydrophobic and two hydrophilic chains) with different lengths of hydrophilic and hydrophobic arms were synthesised on the basis of pyromellitic acid dianhydride. The hydrophilic arms were formed by polyoxyethylene and hydrophobic ones either by perfluoro- or by alkyl chains. The adsorption monolayers (Gibbs monolayers) were studied by surface pressure (π) measurements as a function of time for different surfactant concentrations. For the spread monolayers (Langmuir monolayers), the measurements of the surface pressure (π) versus the molecular area (A) as well as the relaxation measurements of the area (A) as a function of time at constant surface pressure were performed. The comparison between the characteristic parameters of two types of monolayers was made in order to understand the effect of the preparation conditions on the structure of these monolayers.It was found that decreasing the fluoroalkyl chain length induced a systematical decrease in the stability of Langmuir monolayers, which is manifested as the Marangoni-Gibbs viscoelasticity of the monolayers. For the surfactants, which have a large number of oxyethylene groups, adsorption at the air/water interface from the bulk solution required extremely long times to reach equilibrium due to the diffusion from the solution and to the conformational rearrangements at the interface. The observation of a hysteresis in the compression/decompression curves for these compounds is explained by the presence of the residual organic solvent molecules absorbed by oxyethylenic chains. A novel model describing the kinetics of desorption or rearrangement of molecules during the lateral compression was suggested, allowing the estimation of both characteristic time of this process and areas per molecule at the equilibrium from the relaxation curves A(t).     

Study of intermolecular interactions in a system for equilibrium catalytic transesterification of esters. 1. Reaction of boron,titanium, and arsenic butoxides with esters according to IR fourier spectroscopic data

IR spectroscopy was used to study solutions of esters of PhCOOR (R=Me, Bu, C₇H₁₅, (CH₂)₂OBu) in B(OBu)₃, Ti(OBu)₄, and As(OBu)₃ and in mixtures of the latter with CCl₄ and hexane. It is shown that weak complexes form between the ester molecules and B(OBu)₃ and Ti(OBu)₄, As(OBu)₃ behaves with respect to the esters as a nonpolar solvent. Intermolecular interaction of the esters with butoxides occurs at the alkoxide oxygen in the ester. A mechanism of the exchange of the alkoxyl radical in the reaction of Ti(OBu)₄ with PhCOOMe is proposed on the basis of kinetic measurements.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1991–1995, September, 1990.     

New preparative Grignard synthesis of (m-carboranylmethyl)siloxanes from chlorodimethylsiloxanes

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Preparation and properties of fibrous sorbents with grafted nanosized organosiloxane coatings containing complexing aminomethylenephosphonic ligands

We have modified fibrous sorbents with the organosiloxane coating containing aminomethylenephosphonic ligands at silicon atoms. The so prepared materials efficiently absorb ions of some transition metals from solutions in aqueous hydrochloric acid.     

Synthesis and photophysical properties of polyphenylquinoxalines with thiophene and benzothiophene units in side chains

New bis(α-diketones) with thiophene and benzothiophene moieties were synthesized. A series of new polyphenylquinoxalines containing these moieties in side chains was prepared via polycondensation of these diketones with different aromatic tetramines. The polymers are soluble in a variety of organic solvents, and their solutions form transparent films having a tensile strength of σ = 80–100 MPa and an elongation at break of ? = 5–12%. The polymers exhibit fluorescence in solution in trifluoroacetic acid and in films with a maximum at 430–570 and 460–480 nm. The 10% mass loss temperature in air ranges within 440–490°C.