Crystal Chemistry and Physical Properties of the Nonmagnetic Kondo Compound HfAs1.7Se0.2

Single crystals of HfAs_1.7Se_0.2 are grown by chemical transport reaction and their chemical composition characterized in detail by various analytical methods. Chemical analyses and crystal structure investigations by single‐crystal X‐ray diffraction as well as powder diffraction with synchrotron radiation reveal a tetragonal PbFCl structure type with strong disorder caused by a significant arsenic deficiency (As_0.9) on the 2a site and mixed occupancy of the 2c site (As_0.8Se_0.2). HfAs_1.7Se_0.2 is a diamagnetic metal which transforms into a superconducting state at T_c=0.52 K. Similar to other PbFCl‐type arsenide selenides, the title compound displays a magnetic‐field‐independent ?AT^1/2 term in the low‐temperature electrical resistivity. This unusual term presumably originates from the electron scattering of structural two‐level systems. According to the experimental results, HfAs1.7Se0.2 appears to be a rare example of a nonmagnetic Kondo material.     

Determination of the Lipophilicity of Twenty-Seven Imidazo[2,1-c][1,2,4]triazine Derivatives with Strong Biological Activity by Reversed-Phase TLC. Comparison with Results Obtained by Use of Computational Algorithms

JPC – Journal of Planar Chromatography – Modern TLC - The lipophilicity, log P, of 27 novel imidazo[2,1-c][1,2,4]triazine derivatives with strong biological activity has been determined...     

Thermal conductivity enhancement of copper–diamond composites by sintering with chromium additive

The thermal diffusivity (TD) and thermal conductivity (TC) of Cu–Cr–diamond composite materials were examined in the temperature range from 50 to 300 °C for diamond volume fractions of 22, 40, 50, 55, and 60 %. The samples were fabricated by the plasma pulse sintering (PPS) method. TC does not increase proportionally with the diamond fraction in the particular composite materials. The highest TD was determined for 50 % diamond volume fraction, and the evaluated TC reached 658 W m^?1 K^?1 at 50 °C. This article complements earlier articles concerning synthesis and characterization of the diamond–copper composites produced by the PPS method.     

Scope and limitations of the synthesis of functionalized quinolizidinones and related compounds by a simple precursor approach via addition of lithium allylmagnesates to 2-pyridones and RCM as key steps

The scope and limitations of the simple synthesis of functionalized quinolizidin-4-ones by chemoselective N-alkenylation of NH pyridin-2(1H)-ones (2-pyridones), regioselective addition of lithium allyl(di-n-butyl)magnesates(1-) to N-alkenylpyridin-2(1H)-ones, followed by ring closing metathesis (RCM) is described. A number of functionalizations introduced into quinolizidin-4-one rings demonstrated the high prospect of the strategy proposed in scaffold synthesis. Their extension to the syntheses of pyrido[1,2-a]azepin-4-one and pyrido[1,2-a]azocin-4-one derivatives as well as to spiro-fused compounds is also presented.     

Screen-printed reference electrodes for potentiometric measurements

A convenient and reliable method for large-scale production of miniaturized, planar, all-solid-state reference electrodes is reported. All elements of the Ag/AgCl/KCl reference half-cell i.e. layer of Ag/AgCl (inner electrode), immobilized electrolyte (junction) and encapsulation are fabricated by means of screen-printing technology. The use of pastes cured in low temperature allows fabrication on low-cost, plastic, flexible foils. The developed reference electrodes exhibit good long-term stability. Continuous operation life-time exceeds one week. Storage stability is longer than 9 months. pH, chlorides as well as other halide anions, typical buffer components, alkaline and heavy metal cations, complexing ligands and redox agents, do not influence the potential of the reference electrodes. The developed reference electrodes are compatible with strip potentiometric sensors fabricated in the same format. Examples of analytical applications of the reference electrodes with various screen-printed sensors are demonstrated.     

Synthesis,Dissociation Constants,and Antimicrobial Activity of Novel 2,3‐Disubstituted‐1,3‐thiazolidin‐4‐one Derivatives

In this article, a new series of 2,3‐disubstituted‐1,3‐thiazolidin‐4‐one derivatives have been designed, synthesized, and evaluated as antimicrobial agents. New compounds were prepared by the cyclization reaction of N‐substituted carboxylic acid hydrazide derivatives with mercaptoacetic acid. The structures of the obtained compounds were confirmed by means of IR, ¹H NMR, and ¹³C NMR spectra. The dissociation constants were determined using spectrophotometric method. All synthesized compounds were tested for their in vitro antibacterial and antifungal activities using the broth microdilution method.