Novel vic-dioxime ligand containing calix[4]pyrrole moiety: synthesis,characterization, anion binding studies and complexation with Ni(II)

A new vic-dioxime functionalized calix[4]pyrrole was synthesized from anti-chloroglyoxime and 4-aminophenyl-calix[4]pyrrole at room temperature. The Ni(II) complex has been prepared by reacting the ligand with NiCl₂·6H₂O in ethanol. These receptors were characterized by elemental analyses, ¹H and ¹³C NMR spectra, IR and mass spectra. Electrochemical properties of the ligand, and its Ni(II) complex were investigated in CH₂Cl₂ solution by cyclic voltammetry at 100 mV s^?1 scan rate. Anion-binding studies were carried out using UV–Vis, and ¹H NMR titrations, revealed that the Ni(II) complex exhibits selective recognition toward F^? over other anions. The selectivity for F^– among the halides is attributed mainly to the hydrogen-bond interaction of the receptor with F^–. Receptor showed colour change from red to brown in the presence of tetrabutylammonium fluoride (TBAF) with 1:2 stoichiometry.     

Optimizing Urgency of Information through Resource Constrained Joint Sensing and Transmission

Applications requiring services from modern wireless networks, such as those involving remote control and supervision, call for maintaining the timeliness of information flows. Current research and development efforts for 5G, Internet of things, and artificial intelligence technologies will benefit from new notions of timeliness in designing novel sensing, computing, and transmission strategies. The age of information (AoI) metric and a recent related urgency of information (UoI) metric enable promising frameworks in this direction. In this paper, we consider UoI optimization in an interactive point-to-point system when the updating terminal is resource constrained to send updates and receive/sense the feedback of the status information at the receiver. We first propose a new system model that involves Gaussian distributed time increments at the receiving end to design interactive transmission and feedback sensing functions and develop a new notion of UoI suitable for this system. We then formulate the UoI optimization with a new objective function involving a weighted combination of urgency levels at the transmitting and receiving ends. By using a Lyapunov optimization framework, we obtain a decision strategy under energy resource constraints at both transmission and receiving/sensing and show that it can get arbitrarily close to the optimal solution. We numerically study performance comparisons and observe significant improvements with respect to benchmarks.     

Regioselective ring-opening of epoxides with ortho-lithioanisoles catalyzed by BF3·OEt2

It is presented that a number of o-2-hydroxyalkylanisoles could be efficiently synthesized through the regioselective ring-opening reaction of epoxides with o-lithioanisoles in the presence of BF₃·OEt₂ Lewis-acid catalyst. Sterically demanding o-lithioanisoles had to be generated by exploiting the combination of ⁿBuLi and a catalytic amount of TMEDA (0.20 equiv) in Et₂O as the lithiator whereas ‘normal’ anisole could be lithiated at ortho-position by treatment with ⁿBuLi in THF as usual. Surprisingly, the availability of THF and a catalytic amount of TMEDA (0.20 equiv) in the reaction mixture was found to enhance the reaction yields dramatically. A complex aggregate formation by the co-operative ligation of THF and TMEDA to ortho-lithioanisole(s) was proposed to rationalize the high reactivity achieved in the ring-opening reaction of epoxides.     

Sodium magnesium amidoborane: the first mixed-metal amidoborane

The first example of a mixed-metal amidoborane Na(2)Mg(NH(2)BH(3))(4) has been successfully synthesized. It forms an ordered arrangement in cation coordinations, i.e., Mg(2+) bonds solely to N(-) and Na(+) coordinates only with BH(3). Compared to ammonia borane and monometallic amidoboranes, Na(2)Mg(NH(2)BH(3))(4) can release 8.4 wt% pure hydrogen with significantly less toxic gases.     

Synthesis and in vitro antioxidant evaluation of new bis(α-aminoalkyl)phosphinic acid derivatives

Diamines were added to arylaldehydes in ethanol, which resulted in corresponding diimines. Novel bis-1-aminophosphinic acid compounds were synthesized through the interaction of diimines and hypophosphorous acid. The new compounds were characterized by elemental analyses, FT-IR and ¹H, ¹³C and ³¹P NMR techniques. The in vitro antioxidant activity of the newly synthesized compounds were measured and found to exhibit significantly higher antioxidant activity than the standard.     

Composition of Eucalyptus camaldulensis volatiles using direct thermal desorption coupled with comprehensive two-dimensional gas chromatography-time-of-flight-mass spectrometry

The direct qualification and quantitation of the volatile organic components of four Eucalyptus camaldulensis fruit samples, obtained from different geographical areas in Turkey, is studied using a direct thermal desorption (DTD) technique coupled with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry. It is found that the E. camaldulensis sample from Adrasan gave a slightly higher oil yield (1.18%) than the others. The number of components quantitatively identified from Adrasan, Belek, Kuyucak, and Cesme were 46, 54, 55, and 59, respectively. The main compounds found in the volatile oils were: aromadendrene (6.45-15.02%), eucalyptol (0.17-12.61%), gamma-gurjunene (8.40-10.08%), terpinolen (1.98-8.39%), spathulenol (1.42-8.34%), alpha-pinene (0.85-6.81%), ledene (0.94-6.72%), and longifonene (0.07-6.22%). The composition of the volatiles desorbed from samples from all four different areas varied qualitatively and quantitatively. All identified compounds were quantitated using total ion chromatogram peak areas. DTD is a good method for qualitative and/or quantitative analysis of complex mixtures, and in particular for quantitative analysis of plant samples, which can yield data without the traditional obligation for costly and time consuming extraction techniques.     

Synthesis of some azacrown derivatives and fabrication of their nanofilms on the glassy carbon surface

The modification of N-phenyl-aza-15-crown-5 (PA15C5) and N-(4-aminophenyl)-aza-15-crown-5 (4APA15C5) on glassy carbon (GC) electrode was performed by the electrochemical oxidation of the corresponding azacrown derivatives in anhydrous acetonitrile media. The electrochemical behavior of the resulting modified GC electrode was investigated in the presence of electroactive redox probes and these results, together with the X-ray photoelectron spectroscopy (XPS) and reflection-absorption infrared spectroscopy were used to confirm the attachment of these molecules onto the GC surface. The ellipsometric thicknesses of PA15C5 and 4APA15C5 films at the GC surface was obtained around 9.28 ± 0.40 and 10.50 ± 1.10 nm, respectively. Azacrown modified nanoscale surfaces serve as alkali metal sensor specific for their cavity in the crown ring.     

Nanoscale elastic modulus variation in loaded polymeric micelle reactors

Tapping mode atomic force microscopy (TM-AFM) enables mapping of chemical composition at the nanoscale by taking advantage of the variation in phase angle shift arising from an embedded second phase. We demonstrate that phase contrast can be attributed to the variation in elastic modulus during the imaging of zinc acetate (ZnAc)-loaded reverse polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) diblock co-polymer micelles less than 100 nm in diameter. Three sample configurations were characterized: (i) a 31.6 μm thick polystyrene (PS) support film for eliminating the substrate contribution, (ii) an unfilled PS-b-P2VP micelle supported by the same PS film, and (iii) a ZnAc-loaded PS-b-P2VP micelle supported by the same PS film. Force-indentation (F-I) curves were measured over unloaded micelles on the PS film and over loaded micelles on the PS film, using standard tapping mode probes of three different spring constants, the same cantilevers used for imaging of the samples before and after loading. For calibration of the tip geometry, nanoindentation was performed on the bare PS film. The resulting elastic modulus values extracted by applying the Hertz model were 8.26 ± 3.43 GPa over the loaded micelles and 4.17 ± 1.65 GPa over the unloaded micelles, confirming that phase contrast images of a monolayer of loaded micelles represent maps of the nanoscale chemical and mechanical variation. By calibrating the tip geometry indirectly using a known soft material, we are able to use the same standard tapping mode cantilevers for both imaging and indentation.     

Raman micro-spectroscopic analysis of cultured HCT116 colon cancer cells in the presence of roscovitine

Raman micro-spectroscopic analysis of cultured HCT116 colon cancer cells in the presence of roscovitine, [seliciclib, 2-(1-ethyl-2-hydroxy-ethylamino)-6-benzylamino-9-isopropylpurine], a promising drug candidate in cancer therapy, has been performed for the first time. The aim of this study was to investigate modulations in colon cancer cells induced by roscovitine. Raman spectra of the cultured HCT116 colon cancer cells treated with roscovitine at different concentrations (0, 5, 10, 25 and 50 μM) were recorded in the range 400-1850 cm(-1). It was shown that the second derivative profile of the experimental spectrum gives valuable information about the wavenumbers and band widths of the vibrational modes of cell components, and it eliminates the appearance of false peaks arising from incorrect baseline corrections. In samples containing roscovitine, significant spectral changes were observed in the intensities of characteristic protein and DNA bands, which indicate roscovitine-induced apoptosis. Roscovitine-induced apoptosis was also assessed by flow cytometry analysis, and analysis of propidium iodide staining. We observed some modifications in amide I and III bands, which arise from alterations in the secondary structure of cell proteins caused by the presence of roscovitine.