Quantitative analysis of (styrene/acrylonitrile/methyl methacrylate) co-polymer systems by infrared resonance spectroscopy

A detailed careful analysis of the infrared resonance (IR) spectra of polystyrene (PSt), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN) and their co-mixtures were performed. Through this study the absorption peak area to weight ratios as well as working curves were obtained to test for their reliability as well as their suitability. Satisfactory results were achieved and these working curves were then used to measure the polymerized components of binary and ternary co-polymers. By investigating the acquired data we conclude that the monomer preferential polymeric sequence is St > MMA > AN. A quantitative method to measure P (St/AN/MMA) concentrations by IR spectroscopy is proposed in this work.     

Interaction of Pesticides with a β-Cyclodextrin Derivative Studied by Reversed-phase Thin-layer Chromatography and Principal Component Analysis

The interaction of 18 pesticides with a water-soluble -cyclodextrin polymer (BCDP) was studied by reversed-phase thin-layer chromatography and principal component analysis (PCA) was employed for the elucidation of the relationship between the relative strength of interaction and the calculated surface parameters of the guest molecules. Except for penconazole the lipophilicity of the pesticides decrease in the presence of BCDP. PCA indicated that apolar surface parameters are highly positively correlated with the strength of interaction. The data indicate that the agrochemical characteristics (adsorption, leakage, decomposition, etc) of complexed pesticide molecules can be different from those of uncomplexed onesresulting in modified efficacy.     

On Urysohn-Volterra fractional quadratic integral equations

In this paper the authors study a fractional quadratic integral equation of Urysohn-Volterra type. They show that the integral equation has at least one monotonic solution in the Banach space of all real functions defined and continuous on the interval $[0,1]$. The main tools in the proof are a fixed point theorem due to Darbo and a monotonicity measure of noncompactness.     

Thermal properties of gamma-ray irradiated Co–Zn ferrite

Co-Zn ferrite samples of the system Co_1-xZn_xFe₂O₄ (x = 0, 0.2, 0.3, 0.5, 0.6 and 0.8) were prepared using the usual ceramic double sintering technique. Thermal conductivity and specific heat were measured at different temperatures for different compositions. The effect of Co-60 γ-irradiation dose (10⁶ rad) on the thermal conductivity and specific heat were studied.     

Detection of up-conversion in nano-structure BaTiO<Subscript>3</Subscript> co-doped with Er<Superscript>3+</Superscript> and Yb<Superscript>3+</Superscript> ions

Nano-structure pure barium titanate BaTiO₃ (BT) and (BT) co-doped with constant concentration of Er³⁺ ions and different concentrations of Yb³⁺ ions were prepared using sol–gel method. XRD results confirmed that the pure sample was found to crystallize in tetragonal phase by sintering at 750 °C for 1 h. All major peaks corresponding to perovskite BT phase appeared. Efficient infrared-to-visible up-conversion is reported in the doped samples. The conversion process and results in the generation of visible emissions are discussed. Up-conversion efficiency for red emission predominates in doped samples. Results illustrate the large potential of this class of materials for photonic applications in optoelectronics devices.     

Synthesis of Novel Tridentate 5-Arylazosalicylaldehyde Thiosemicarbazone Derivatives and Their Complexes with Copper(II)

Russian Journal of General Chemistry - Herein, novel 5-arylazosalicylaldehyde thiosemicarbazone derivatives (H2L1–12) and their copper(II) complexes have been synthesized and characterized by...     

Synthesis and characterisation of Fe6 and Fe12 clusters using bicine

Reaction of bicine {BicH₃, N,N-bis(2-hydroxyethyl)glycine} with an Fe(III) oxo-centered pivalate triangle in MeCN in the presence of Et₂NH yields [Et₂NH₂]₂[Fe₆O₂(OH)₂(Bic)₂(O₂CCMe₃)₈], which possesses an S = 5 ground state.Changing the base to NaOMe produces [Fe₁₂O₄(Bic)₄(HBic)₄(O₂CCMe₃)₈], which contains two Fe₆ units bridged by the carboxylate arms from the bicine ligands. The complex displays strong antiferromagnetic coupling leading to an S = 0 ground state.     

Microwave-assisted solution-phase synthesis and DART-mass spectrometric monitoring of a combinatorial library of indolin-2,3-dione schiff bases with potential antimycobacterial activity

A combinatorial library composed of eleven hydrazides A-K and eleven indolin-1,2-dione derivatives 1-11 has been designed to formally generate sublibraries of 22 mixtures, M(1)-M(22) comprising of 121 Schiff bases, A-K(1-11). The designed library has been synthesized by the solution-phase method and microwave-assisted synthetic techniques. The formation of individual compounds of each mixture was confirmed by Direct Analysis in Real Time (DART) as ionization technique connected to an Ion Trap as a mass detector. The synthesized mixtures were evaluated for their antimycobacterial activity against four Mycobacterium strains; M. intercellulari, M. xenopi, M. cheleneoi and M. smegmatis. Variable antimycobacterial activity was revealed with the investigated mixtures and maximum activity was shown by M(8), M(10), M(11), and M(15) with MIC values of 1.5, 3.1, 6.2 and 0.09 μg/mL, respectively. Application of the indexed method of analysis on these active mixtures revealed that compounds D(8), D(10) and D(11) may contribute to the activity of the tested mixtures.     

Synthesis and X-ray crystal structures of imido and ureato derivatives of titanium(IV) phthalocyanine and their application in the catalytic formation of carbodiimides by metathesis from isocyanates

The imido titanium phthalocyanine complex [PcTi(NDip)] (Dip = 2,6-diisopropylphenyl) 2a was synthesized from [PcTiO] 1 and one eq. of DipNCO. Due to the steric demand of the Dip group, addition of another isocyanate molecule to the Ti = N functionality of 2a does not occur even at high molar ratios of DipNCO. However, 1 reacts with 2 eq. of arylisocyanates containing sterically less demanding aryl groups producing N,N'-diarylureatotitanium(iv)phthalocyanines [PcTi{κ(2)-(NR)C(O)(N'R)}] (R = p-tolyl (Tol) 3a or mesityl (Mes) 3b). The N,N' coordination (III) of the ureato ligand in 3a and 3b was proven by a single set of resonances for the aryl groups in their (1)H-NMR spectra. An N,O coordination (IV) can therefore be excluded. This is also confirmed by the X-ray crystal structure of 3a. Upon heating [PcTiO] and an excess of aryl isocyanates for 6 days, a steady evolution of CO(2) was observed and a white precipitate, identified as the corresponding diarylcarbodiimides (V), could be isolated. Therefore this reaction was applied in the metathetic conversion of two isocyanate molecules into diarylcarbodiimides (V) and CO(2). Additionally, imido titanium Pc's 2b (R = tBu) and 2c (R = Mes) were prepared by a more general synthetic strategy, reacting the potassium salt of the ligand PcK(2) with appropriate imido titanium precursors.