Retracted: A new class of copper(I) complexes with imine-containing chelators which show potent anticancer activity

Seven novel complexes (C₁–C₇) were synthesized by the interaction between Cu(I) metal cation, L₁, L₂, L₃, X and PPh₃, where L₁–L₃ are derivatives of ((pyridine-2-ylmethylene)amino)phenol imine ligands and X = Cl⁻, Br⁻, I⁻, NCS⁻. All the complexes were characterized using infrared, ¹H NMR and ³¹P NMR spectroscopies. The crystal structures of C₁–C₇ were also determined using single-crystal X-ray diffraction. The organization of the crystal structures and the intermolecular interactions are discussed. The supramolecular assemblies are driven by cooperative π…π interactions and hydrogen bonds, followed by CH…π linkages. The potential anticancer effect of C₁–C₇ was assessed for human glioblastoma cells using several anticancer experiments, which showed that these complexes have marked anticancer property against U87 cells. It was also found that the minimum and maximum anticancer effects are shown by C₃- and C₄-treated samples, respectively. Furthermore, theoretical approaches were used to investigate the nature of metal–ligand interactions which suggest a closed-shell and electrostatic character for Cu…N, Cu…P and Cu…X bonds.     

Label-free detection of charged macromolecules by using a field-effect-based sensor platform: Experiments and possible mechanisms of signal generation

The possibilities and limitations of a direct electrical detection of charged macromolecules using a field-effect-based sensor platform is evaluated, mainly focusing on capacitive EIS (electrolyte-insulator-semiconductor) devices. The experimentally obtained results on the detection of DNA immobilisation and hybridisation as well as the monitoring of layer-by-layer adsorbed charged polyelectrolyte (PE) multilayers have been discussed by using two basic possible mechanisms of signal generation, namely the intrinsic charge of the macromolecules and the charge redistribution within the intermolecular spaces or in the multilayer. The effects of the layer-by-layer adsorption conditions (unbuffered and pH buffer solution), and the number and polarity of charged layers on the sensor response have been systematically investigated by means of capacitance–voltage (C–V), constant–capacitance (ConCap) and impedance spectroscopy (IS) methods. PACS 82.47.Rs; 82.80.Fk; 85.30.Tv; 87.15.Kg; 87.14.Gg     

Investigation of MHD effect on nanofluid heat transfer in microchannels

Journal of Thermal Analysis and Calorimetry - An incompressible preconditioned lattice Boltzmann method (IPLBM) is proposed to investigate the fluid flow and heat transfer characteristics of...     

Acidity and Hydrogen Exchange Dynamics of Iron(II)‐Bound Nitroxyl in Aqueous Solution

Nitroxyl‐iron(II) (HNO‐Fe^II) complexes are often unstable in aqueous solution, thus making them very difficult to study. Consequently, many fundamental chemical properties of Fe^II‐bound HNO have remained unknown. Using a comprehensive multinuclear (¹H, ¹⁵N, ¹⁷O) NMR approach, the acidity of the Fe^II‐bound HNO in [Fe(CN)₅(HNO)]³⁻ was investigated and its pK_a value was determined to be greater than 11. Additionally, HNO undergoes rapid hydrogen exchange with water in aqueous solution and this exchange process is catalyzed by both acid and base. The hydrogen exchange dynamics for the Fe^II‐bound HNO have been characterized and the obtained benchmark values, when combined with the literature data on proteins, reveal that the rate of hydrogen exchange for the Fe^II‐bound HNO in the interior of globin proteins is reduced by a factor of 10⁶.     

Analysis of Capillary–Viscous–Gravity Forces in Biopolymer Flooding with a Sensitivity Analysis on Polymer and Porous Medium Parameters

Gravity, viscous, and capillary are three main forces affecting flow characteristics in porous media. No analytical solution can be found to model the flow by considering all these forces. In this work, by considering all these forces, the polymer-flooding process is modeled by using a numerical simulation approach. For characterizing the polymer, the modified Blake–Kozeny model is chosen, which benefits consideration of the permeability reduction due to polymer adsorption on the rock surface.     

Solving the 170‐Year‐Old Mystery About Red‐Violet and Blue Transient Intermediates in the Gmelin Reaction

The Gmelin reaction between nitroprusside and sulfides in aqueous solution is known to produce two transient intermediates with distinct colors: an initial red‐violet intermediate that subsequently converts into a blue intermediate. In this work, we use a combination of multinuclear (¹⁷O, ¹⁵N, ¹³C) NMR, UV/Vis, IR spectroscopic techniques and quantum chemical computation to show unequivocally that the red‐violet intermediate is [Fe(CN)₅N(O)S]^4? and the blue intermediate is [Fe(CN)₅N(O)SS)]^4?. While the formation of [Fe(CN)₅N(O)S]^4? has long been postulated in the literature, this study provides the most direct proof of its structure. In contrast, [Fe(CN)₅N(O)SS)]^4? represents the first example of any metal coordination complex containing a perthionitro ligand. The new reaction pathways found in this study not only provide clues for the mode of action of nitroprusside for its pharmacological activity, but also have broader implications to the biological role of H₂S, potential reactions between H₂S and nitric oxide donor compounds, and the possible biological function of polysulfides.     

An Analytic Solution for the Frontal Flow Period in 1D Counter-Current Spontaneous Imbibition into Fractured Porous Media Including Gravity and Wettability Effects

Including gravity and wettability effects, a full analytical solution for the frontal flow period for 1D counter-current spontaneous imbibition of a wetting phase into a porous medium saturated initially with non-wetting phase at initial wetting phase saturation is presented. The analytical solution applicable for liquid–liquid and liquid–gas systems is essentially valid for the cases when the gravity forces are relatively large and before the wetting phase front hits the no-flow boundary in the capillary-dominated regime. The new analytical solution free of any arbitrary parameters can also be utilized for predicting non-wetting phase recovery by spontaneous imbibition. In addition, a new dimensionless time equation for predicting dimensionless distances travelled by the wetting phase front versus dimensionless time is presented. Dimensionless distance travelled by the waterfront versus time was calculated varying the non-wetting phase viscosity between 1 and 100 mPas. The new dimensionless time expression was able to perfectly scale all these calculated dimensionless distance versus time responses into one single curve confirming the ability for the new scaling equation to properly account for variations in non-wetting phase viscosities. The dimensionless stabilization time, defined as the time at which the capillary forces are balanced by the gravity forces, was calculated to be approximately 0.6. The full analytical solution was finally used to derive a new transfer function with application to dual-porosity simulation.