MHD mixed convection in a nanofluid filled vertical lid-driven cavity having a flexible fin attached to its upper wall

Journal of Thermal Analysis and Calorimetry - In this study, fluid flow and heat transfer in a vertical lid-driven CuO–water nanofluid filled square cavity with a flexible fin attached to its...     

Control of combined convection in a nanofluid-filled lid-driven closed space via rectangular bar in the presence of magnetic field

Journal of Thermal Analysis and Calorimetry - In the present study, a computational work has been done to see the heat transfer, fluid flow and temperature distribution in a lid-driven cavity due...     

Synthesis,characterization and H<Subscript>2</Subscript> adsorption performances of polymeric Co(II) and Ni(II) complexes of pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole

We studied the synthesis and characterization of polymeric coordination complexes of Co(II) and Ni(II) ions with pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole. The e lemental analysis, infrared spectroscopy, powder X-ray diffraction, magnetic susceptibility, thermal analysis and X-ray single crystal techniques were used in the characterization. The X-ray single crystal analysis suggests that the pyrazine-2,3-dicarboxylato ligand acts as a bridging ligand through the oxygen atoms of the carboxylate groups and the nitrogen atoms on the pyrazine ring. The 1-vinylimidazole ligand behaves as a monodentate ligand via the ring nitrogen atom. Further, the H₂ adsorption studies were carried out at 75 K for various increasing pressures and the highest H₂ adsorption performances for Co(II) and Ni(II) complexes were estimated as 2.66 and 2.99 wt% at 87 bar. The theoretical calculations using the crystal data were also performed to determine the voids in the structure of Co(II) complex.     

Crystal structure of [RuCl2[N-(2,4,6-trimethyl-benzyl)N-(n-butyl)]-imidazolidin-2-ylidene] and [RuCl2[N-(2,4,6-trimethyl-benzyl)-N-(2-methoxyethyl)]-imidazolidin-2-ylidene]

Two imidazolidin ruthenium complexes, [RuCl₂{[N-(2,4,6-trimethyl-benzyl)-N-(n-butyl)]-imidazolidin-2-ylidene}], 1, and [RuCl₂{[N-(2,4,6-trimethyl-benzyl)-N-(2-methoxyethyl)]-imidazolidin-2-ylidene}], 2, have been synthesised and their crystal structures have been determined from single crystal X-ray diffraction data. Compound 1 is monoclinic, of space group C2/c with a = 18.466(4) Å, b = 14.816(3) Å, c = 15.413(3) Å, β = 118.067(2)^∘, and V = 3720.9(12) ų with Z = 8 for d_calc = 1.536 g/cm³. Compound 2 is monoclinic, of space group P2₁/c with a = 8.1800(5) Å, b = 14.344(8) Å, c = 14.809(9), β = 91.604(10)^∘, and V = 1736.7(18) ų with Z = 4 for d_calc = 1.653 g/cm³. In each complex the ligand functions as an arene and carbene, occupying four coordination sites. The two chlorines in each compound complete a distorted octahedron.     

Novel metallophthalocyanines bearing 3-(p-chlorophenyl)-5-p-tolyl-4H-1,2,4-triazole bulky substituents by microwave irradiation

The synthesis of metallophthalocyanines [6–9; M = Ni(II), Zn(II), Co(II) and Cu(II)] with four 1,2,4-triazole units obtained from 4-{(4-chloro-2-fluorobenzyl)[3-(4-chlorophenyl)-5-(4-methylphenyl)-4H-1,2,4-triazol-4-yl]amino}phthalonitrile (5) in the presence of dimethylaminoethanol and the corresponding anhydrous metal salts is described. The thermal stabilities of the Pc compounds were determined by thermogravimetric analysis. The new compounds were characterized by a combination of IR, ¹H NMR, ¹³C NMR, UV–Vis, elemental analysis.     

Organic/inorganic interfaced field-effect transistor properties with a novel organic semiconducting material

A novel 1,3,4-oxadiazole-substituted benzo[b]triphenylene was synthesized by three-step synthetic procedure and OFET device design was successfully designed after theoretical calculations made using Gaussian software. For investigating the field-effect properties of designed organic electronic device, a SiO₂ (300 nm) was thermally grown on p-Si wafer at 1000 °C as a dielectric layer and gate, source and drain contacts have been deposited using Au metal with physical vapour deposition. 1,3,4-Oxadiazole-substituted benzo[b]triphenylene was spin coated on the source and drain electrodes of our device, forming organic/inorganic interfaced field-effect transistors. Surface morphology and thin film properties were investigated using AFM. All electrical measurements were done in air ambient. The device showed a typical p-type channel behaviour with increasing negative gate bias voltage values. Our results have surprisingly shown that the saturation regime of this device has high mobility (μ_FET), excellent on/off ratio (I_on/I_off), high transconductance (g_m) and a small threshold voltage (V_Th). The values of μ_FET, I_on/I_off, g_m and V_Th were found as 5.02 cm²/Vs, 0.7 × 10³, 5.64 μS/mm and 1.37 V, respectively. These values show that our novel organic material could be a potential candidate for organic electronic device applications in the future.     

Influence of the bridging ligand on the substitution behaviour of dinuclear Pt(II) complexes. An experimental and theoretical approach

A series of dinuclear Pt(II) complexes of the type [Pt2(N,N,N',N'-tetrakis(2-pyridylmethyl)diamine(H2O)2]4+ were synthesized. Acid-base titrations, and concentration and temperature dependent stopped-flow measurements of the reaction with chloride were performed to study the thermodynamic and kinetic behaviour of the dinuclear bridged complexes. The results indicate that there is a clear interaction between the two Pt(II) centres, which becomes weaker as the aliphatic chain increases in length. From a certain chain length onwards, the Pt(II) centres become independent of each other and exhibit identical thermodynamic and kinetic properties. The experimental results are discussed in reference to structures obtained by DFT (BP86/LACVP*) calculations.     

The reaction OF N‐dichlorophosphoryl‐ P‐trichlorophosphazene with alkyl grignard reagents

The reactions of N‐dichlorophosphoryl‐P‐trichlorophosphazene Cl₃PN P(O)Cl₂ ( 1 ) with benzylmagnesium bromide, 2‐phenylethylmagnesium bromide, trimethylsilylmethylmagnesium chloride, n‐butylmagnesium bromide, cyclohexylmagnesium bromide, cyclopentylmagnesium bromide, tert‐butylmagnesium bromide, iso‐propylmagnesium bromide, and ethylmagnesium bromide were studied. Tri‐ and pentaalkyl phosphazenes were obtained in very poor yield from trimethylsilylmethylmagnesium chloride and cyclohexylmagnesium bromide, respectively. Trialkylphosphoryl compounds formed from benzyl‐, 2‐phenylethyl‐, and n‐butylmagnesium bromide. No phosphorus compound could be isolated from the reaction of 1 with t‐butyl‐, cyclopentyl‐, iso‐propyl‐, and ethylmagnesium bromide. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:413–416, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10153     

Visual detection of Al ions using conjugated copolymer-ATP supramolecular complex

A colorimetric Al³⁺ sensor based on fluorescence recovery of a conjugated copolymer-ATP complex is proposed. An optimized ratio of two polythiophene (PT) monomers is utilized to synthesize copolymer (CP) that yielded maximized colorimetric response for Al³⁺ in deionized (DI) and tap water. The electrostatic disassembly of CP-ATP upon addition of Al³⁺ led to an evident visual color change. The lowest concentration of Al³⁺ for naked eye observation is around 4 μM, which is below the threshold levels in drinking water according to European Economic Community (EEC) standard. Besides, the proposed assay showed a similar response to Al³⁺ in tap water. The proposed methodology showed selective and sensitive detection for Al³⁺ in analytically relevant concentration ranges without involving sophisticated instrumentation, illustrating the applicability for on-site drinking water monitoring.