Центральная Научная Библиотека УрО РАН

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   C 91


    Crystal structure of N-(3-hydroxypropyl)-beta-alanine and Bis(N-(3-hydroxypropyl)-beta-alaninato)dicopper(II) [Cu2 (Pro-ala)2] [Electronic resource] / A. V. Pestov, P. A. Slepukhin, L. S. Molochnikov, M. A. Ezhikova, M. I. Kodess, Yu. G. Yatluk // Russian Journal of Inorganic Chemistry (Zhurnal Neorganicheskoi Khimii). - 2010. - Vol. 55, № 2. - P201-208

ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Аннотация: N-(3-Hydroxypropyl)-beta-alanine was synthesized by the reacti on of 3-aminopropanol with acrylic acid. From this ligand and basic copper carbonate, bis(N-(3-hydroxypropyl)-beta-alaninato)dicopper(II) [Cu2 (C6H11NO3)2] was obtained. The structures of the chelating agent and the copper complex were studied by X-ray diffraction. The Cu(II) coordination polyhedron is a distorted square pyramid. Each ligand forms six-membered ?-alaninate and propanolamine chelate rings. The propoxy group functions as a bridge. In the crystal structure, the molecules form intermolecular coordination bonds C=OCu, which are perpendicular to the layers. The EPR signal typical of dimeric copper complexes is not observed due to low occupancy of the excited paramagnetic triplet state. The weak paramagnetic signal from monomeric copper complex allowed recording of the 1H NMR spectrum of [Cu2 (Pro-ala) 2] with characteristic line broadening and contact shift. It follows from the obtained data that on dissolution, the complex dissociates by 40% to give monomeric copper complexes

\\\\Expert2\\nbo\\Russian Journal of Inorganic Chemistry\\2010, v. 55, N 2, с.201.pdf
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   S 54

    Shishmakov, A. B.
    Concise synthesis of silver-containing titania xerogels / A. B. Shishmakov, Yu. V. Mikushina // Russian Journal of Applied Chemistry. - 2021. - Vol. 94, № 7. - P879-883

ББК Г
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Кл.слова (ненормированные):
XEROGEL -- CALCINATION -- TITANIUM DIOXIDE -- SILVER
Аннотация: A concise procedure was developed for the synthesis of silver-containing xerogels Ag(0)/TiO2 [0.23.2 wt % Ag(0)], including the dissolution of AgNO3 in tetrabutoxytitanium, hydrolysis of the solution in acetic acid–water vapors, drying, and calcining the xerogel at 600–800°C. It was found by X-ray diff raction analysis and electron microscopy that the bulk of metallic silver particles (75–90%) in the material calcined at 800°C has a size of 25–45 nm. The fraction of particles (in the form of crystal intergrowths) with a diameter of 95–115 nm rises with an increase in the AgNO3 concentration at the dissolution stage; TiO2 is present in the rutile phase. At a calcination temperature of 600°C, the dominant TiO2 phase (72%) is anatase; in this case the size of silver particles is 5–10 nm.

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    Stimuli-responsive dual cross-linked N-carboxyethylchitosan hydrogels with tunable dissolution rate / S. Bratskaya, A. Skatova, Y. Privar [et al.] // Gels. - 2021. - Vol. 7, № 4. - Ст. 188
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Кл.слова (ненормированные):
HYDROGELS -- CHITOSAN -- SALICYLALDEHYDE
Аннотация: Here, we discuss the applicability of (methylenebis(salicylaldehyde)—MbSA) for the fabrication of the stimuli-responsive N-carboxyethylchitosan (CEC) hydrogels with a tunable dissolution rate under physiological conditions. In comparison with non-covalent salicylimine hydrogels, MbSA cross-linking via covalent bis(‘imine clip’) and non-covalent hydrophobic interactions allowed the fabrication of hydrogels with storage moduli > 1 kPa at ten-fold lower aldehyde/CEC molar ratio with the preservation of pH- and amino-acid responsive behavior. Although MbSA-cross-linked CEC hydrogels were stable at neutral and weakly alkaline pH, their disassembly in cell growth medium (Dulbecco’s modified Eagle’s medium, DMEM) under physiological conditions was feasible due to transimination reaction with amino acids contained in DMEM. Depending on the cross-linking density, the complete dissolution time of the fabricated hydrogels varied from 28 h to 11 days. The cytotoxicity of MbSA cross-linked CEC hydrogels toward a human colon carcinoma cell line (HCT 116) and primary human dermal fibroblasts (HDF) was remarkably lower in comparison with CEC-salicylimine hydrogels. Fast gelation, relatively low cytotoxicity, and tunable stimuli-induced disassembly under physiological conditions make MbSA cross-linked CEC hydrogels promising for drug encapsulation and release, 3D printing, cell culturing, and other biomedical applications.

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    Chitosan cross-linking with acetaldehyde acetals / A. Pestov, Y. Privar, A. Slobodyuk [et al.] // Biomimetics. - 2022. - Vol. 7, № 1. - Ст. 10
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Кл.слова (ненормированные):
CHITOSAN -- ACETALDEHYDE ACETALS -- HYDROGEL
Аннотация: Here we demonstrate the possibility of using acyclic diethylacetal of acetaldehyde (ADA) with low cytotoxicity for the fabrication of hydrogels via Schiff bases formation between chitosan and acetaldehyde generated in situ from acetals in chitosan acetate solution. This approach is more convenient than a direct reaction between chitosan and acetaldehyde due to the better commercial availability and higher boiling point of the acetals. Rheological data confirmed the formation of intermolecular bonds in chitosan solution after the addition of acetaldehyde diethyl acetal at an equimolar NH2: acetal ratio. The chemical structure of the reaction products was determined using elemental analysis and 13C NMR and FT-IR spectroscopy. The formed chitosan-acetylimine underwent further irreversible redox transformations yielding a mechanically stable hydrogel insoluble in a broad pH range. The reported reaction is an example of when an inappropriate selection of acid type for chitosan dissolution prevents hydrogel formation.

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