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Based on 1,3-bis(2-methylbenzimidazole)propane (L1), 1,4-bis(2-methylbenzimidazole)butane (L2) and 1,4-bis(2-methylbenzimidazol-1-ylmethyl)benzene (L3) with aromatic carboxylic acids, three cocrystals, [(HL1)·2(Hbtrc)] ( 1), [(HL2)·(Hbtec)·2HO] ( 2) and [(HL3)·(Hbtec)] ( 3) (Hbtrc = 1,2,4-benzenetricarboxylic acid, Hbtec = 1,2,4,5-benzenetetracarboxylic acid) were synthesized in solution and obtained by slow evaporation. All solid products were characterized by elemental analyses, IR spectra, and single-crystal X-ray diffraction. Components of the crystalline phase have also been investigated in terms of Hirshfeld surfaces. The bis(benzimidazole) derivatives interlinked with aromatic carboxylates through intermolecular H-bonding and π- π interactions generate diverse 3D supramolecular networks for 1, 2, and 3. The Hirshfeld surfaces and 2D fingerprint plots of three cocrystals show that 1- 3 are stabilized by N-H···O, O-H···O, and π- π intermolecular interactions. The thermal stabilities and photoluminescence properties for cocrystals 1- 3 were presented in the solid state. [ABSTRACT FROM AUTHOR]

Abstract: A planar, impedancemetric NO2 sensor with 8% yttria stabilized zirconia (YSZ) as electrolyte and NiO nanoparticles as sensing electrode and a Pt counter electrode was fabricated and tested. The nano-structured NiO sensing electrode was fabricated by infiltrating aqueous solutions of nickel nitrate into porous layer in a bilayer yttria-stabilized zirconia (YSZ) pellet, followed by calcination at 800°C for 3h. The complex impedance of the device was measured in the frequency range of 0.1–100kHz and in the temperature range of 500–600°C, respectively. The resistance value (Z′) of the device at low frequency varied with concentration of NO2 in sample gases. The response signal (|Z|base−|Z|gas) at 0.1Hz of the present device was found to vary almost linearly with the logarithm of NO2 concentration from 20 to 300ppm at fixed oxygen concentrations at 500–600°C. The present sensor has many advantages, such as, simple structure, easy preparation, fast response and high sensitivity. [Copyright &y& Elsevier]