Synthesis,crystal structure and spectral characteristics of highly fluorescent chalcone-based coumarin in solution and in polymer matrix

A new coumarin chalcone 3-((2E)-3-(2-hydroxyphenyl) prop-2-enoyl)-4-hydroxy-2(H)-chromen-2-one was synthesized using the Claisen Schmidt reaction by the condensation of 3-acetyl-4-hydroxycoumarin and 2-hydroxybenzaldehyde using a mild organic base. This novel compound was characterized by ¹H NMR, FT-IR and UV–vis spectroscopy. Single crystal X-ray diffraction investigation at low temperature (T=120 K) shows that this compound exhibits an intramolecular O3–H…O hydrogen bond, the coumarin ring and the phenyl group are nearly coplanar and the crystal packing is stabilized by intermolecular O3–H…O contacts and π–π stacking interactions. This ortho-hydroxyphenyl-4-hydroxycoumarin chalcone exhibits a strong blue-green emission under visible light excitation at 470 nm. The fluorescence behaviors of this compound doped in poly(methyl methacrylate) (PMMA) were investigated.     

On partitions of {1,…,2m + 1}\{k} into differences d,…,d + m − 1: Extended Langford sequences of large defect

It is shown that for m = 2d ? 1, 2d, 2d + 1, and d ≥ 1, the set {1, 2,…, 2m + 2}, ? {2,k} can be partitioned into differences d,d + 1,…,d + m ? 1 whenever (m,k) ≡ (0,0), (1,d + 1), (2, 1), (3,d) (mod (4,2)) and (d,m,k) ≠ (1,1,3), (2,3,7) (where (x,y) ≡ (u,ν) mod (m,n) iff x ≡ u (mod m) and y ≡ ν (mod n)). It is also shown that if m ≥ 2d ? 1 and m ? [2d + 2, 8d ? 5], then the set {1, 2, …, 2m + 1} ? {k} can be partitioned into differences d,d + 1,…,d + m ? 1 whenever (m,k) ≡ (0, 1), (1,d), (2,0), (3,d + 1) mod (4,2). Finally, for d = 4 we obtain a complete result for when {1,…,2m + 1} ? {k} can be partitioned into differences 4,5,…,m + 3. © 2004 Wiley Periodicals, Inc.     

Surface modification of oxidized cellulose haemostat by argon plasma treatment

In this paper we focused on cold plasma treatment of oxidized cellulose haemostat. Oxidized cellulose was modified in inert argon plasma. The changes of surface composition were examined by XPS and FTIR. Surface morphology of fibres was studied by SEM. Gravimetry was used to study ablation and water absorption. Antibacterial effect of pristine and plasma treated samples was examined by growth of Escherichia coli and Staphylococcus epidermidis. Behaviour of pristine and plasma treated samples in water, physiological saline solution and phosphate buffered saline was observed by changes in the pH of their solutions. Modification of oxidized cellulose by inert argon plasma caused significant changes in the chemical composition of its surface layers as well as changes in morphology of those layers while maintaining or improving the antibacterial properties. We found out that modification by inert argon plasma improves the properties necessary for haemostatic function of oxidized cellulose.     

II Siberian Seminar on Molecular Electronics

II Siberian Seminar on Molecular Electronics     

The incommensurate modulation in the Bi2Sr2−xCaxCuO6 superconductor, and its relation to the modulation in Bi2Sr2−xCaxCu2O8

The modulation of the (221) superconducting Bi₂Sr_2−xCa_xCuO₆ phase has been analyzed by X-ray diffraction, using four-dimensional symmetry theory. The pseudo-orthorhombic diffraction pattern is a superposition of two twin related components, such that the main reflections with hkl and hk m superimpose, but the satellite hklm and hk m do not. The latter feature allows separation of the twin intensities. The modulation analysis in superspace group P:Aa:1 shows displacements similar to those observed in the 2212 compound [Y. Gao et al., Science 241 (1988) 954] but with generally larger displacements. In particular, the c-axis displacement amplitude of the Cu atoms is increased to almost 0.5 Å. This and the obliqueness of the q vector (q=0.214a^*+0.61c^*) indicate the absence of a restraining influence exerted by the CuO₂/Sr(Ca)/CuO₂ double layers in the multi-Cu layer phases.     

Tuning of PEDOT:PSS Properties Through Covalent Surface Modification

Conductive polymer (poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS) is an attractive platform for the design of flexible electronic, optoelectronic, and (bio)sensor devices. Practical application of PEDOT:PSS often requires an incorporation of specific molecules or moieties for tailoring of its physical–chemical properties. In this article, a method for covalent modification of PEDOT:PSS using arenediazonium tosylates was proposed. The procedure includes two steps: chemisorption of diazo‐cations on the PEDOT:PSS surface followed by thermal decomposition of the diazonium salt and the covalent bond formation. Structural and surface properties of the samples were evaluated by XPS, SEM‐EDX, AFM, goniometry, and a range of electric and optical measurements. The developed modification procedure enables tuning of the PEDOT:PSS surface properties such as conductivity and optical absorption. The possibility to introduce various organic functional groups (from hydrophilic to hydrophobic) and to create new groups for further functionalization makes the developed procedure multipurpose. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 378–387     

Gluing Langmuir-Blodgett monolayers onto hydrocarbon surfaces

This paper describes a new approach for modifying hydrophobic surfaces that is based on the use of ionically cross-linked (i.e., "glued") Langmuir-Blodgett monolayers. Specifically, this work shows how monolayers of 5,11,17,23,29,35-hexa(trimethylammonium methyl)-37,38,39,40,41,42-hexakis-n-hexadecyloxy-calix[6]arene (1a), which have been ionically cross-linked with poly(4-styrene-sulfonate) (PSS, MW 30,000-50,000), can be deposited onto silylated silicon wafers with their polar headgroups extending outward into air. This work also demonstrates the feasibility of using glued monolayers of 1a as "anchors" for attaching alternating layers of poly(diallyldimethylammonium) [PDADMA] and PSS ions onto these same hydrocarbon surfaces.     

Cubic octanuclear aluminum fluoride phosphonate

A crystalline complex [Al8F12{(CH3)2C(NH3)PO3}12] (1) was isolated from the supernatant of the hydrothermal reaction of gibbsite Al(OH)3 with 1-amino-1-methyl-ethylphosphonic acid (AIPA) and the HF mineralizer. The single-crystal X-ray diffraction analysis revealed a highly symmetrical cubic Al8F12 core with aluminum atoms at the corners, bridging fluorides spanning all edges, and 12 bidentate bridging phosphonate ligands completing the octahedral coordination sphere of aluminum centers. The stability of the complex in solution was established by electrospray mass spectrometry and the high molecular symmetry (Th) was reflected in the appearance of single resonances in the 1H, 19F, and 31P NMR spectra.     

Lateral Vortex Dynamics behind Ahmed body

The flow-field in the wake of Ahmed body was studied experimentally. The study is oriented on unsteady behavior of the lateral vortex pair arising in the wake as well as on the wake itself. The time-mean characteristics of the wake flow are presented. The dynamical behavior of the longitudinal vortex pair is studied in details. The Stereo Time-Resolved PIV method was applied in the wake plane perpendicular to the mean flow. Two variants of Ahmed Body with slat angle 25 and 35 degrees are investigated respectively. Comparison shows considerable differences in the vortex pair topology and dynamics of the cases in question. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Smooth extension of norms and complementability of subspaces

Research supported in part by NSERC (Canada), Grant A7926.