Shafiq Ullah

New supramolecular ferrocenyl amides: synthesis, characterization, and preliminary DNA-binding studies

Three ferrocenyl amides have been synthesized and characterized by analytical techniques. Based on single-crystal X-ray analysis, a supramolecular structure was attributed to 1 owing to the presence of intermolecular non-covalent interactions. UV-Visible spectroscopy, viscometry, and dynamic laser light scattering was used to assess the mode of interaction and binding of these complexes with DNA, which varied in the sequence 1 > 2 > 3. The binding is presumably due to the ability of these complexes to form secondary non-covalent interactions with DNA bases. Complex-DNA adduct formation depends on the nature of R of the amide.

Study of New Ferrocene Incorporated N,N′-Disubstituted Thioureas as Potential Antitumour Agents

In this paper, we report the synthesis, structural characterisation, cytotoxicity against human ovarian tumour models (A2780, A2780cisR, and A2780ZD0473R), nature of interaction with calf-thymus (CT)-DNA and pBR322 plasmid DNA of new ferrocene based N,N′-disubstituted thioureas (3a–d). The compounds, characterized based on elemental analysis, FT-IR and multinuclear (1H and 13C) NMR spectroscopy, and single crystal X-ray diffractometry, were found to have significant antitumour activity although much less than cisplatin. Crystallographic data reveals the existance of secondary interactions for compound 3c in terms of intermolecular hydrogen bonding of type NH⋯O, NH⋯S and secondary non-covalent interactions (π⋯H). When pBR322 plasmid DNA was interacted with increasing concentrations of compounds, 3a and 3b but not 3c were found to partially prevent BamH1 digestion of the DNA. The negative shift in peak potential in voltammetric measurements indicates that all the compounds undergo electrostatic interactions with the negatively charged phosphate DNA backbone. The large negative value of the binding energy indicates the spontaneity of reaction between the compounds and CT-DNA and the conformational stability of adducts formed.

Solvothermal Preparation of ZnO Nanorods as Anode Material for Improved Cycle Life Zn/AgO Batteries

Nano materials with high surface area increase the kinetics and extent of the redox reactions, thus resulting in high power and energy densities. In this study high surface area zinc oxide nanorods have been synthesized by surfactant free ethylene glycol assisted solvothermal method. The nanorods thus prepared have diameters in the submicron range (300∼500 nm) with high aspect ratio. They have uniform geometry and well aligned direction. These nanorods are characterized by XRD, SEM, Specific Surface Area Analysis, solubility in alkaline medium, EDX analysis and galvanostatic charge/discharge studies in Zn/AgO batteries. The prepared zinc oxide nanorods have low solubility in alkaline medium with higher structural stability, which imparts the improved cycle life stability to Zn/AgO cells.

Low-temperature Synthesis of Nanocrystalline LiNi0.5Mn1.5O4 and its Application as Cathode Material in High-power Li-ion Batteries

Nickel-doped lithium manganate spinels are a potential material for future energy storage owing to high cell potential and low price. Phase-pure spinels are difficult to prepare by conventional solid-state synthesis methods owing to loss of oxygen from the crystal lattice at high temperature (~800°C). Loss of oxygen causes Jahn–Teller distortion and Mn4+ is converted into Mn3+, which results in undesired double-plateau discharge and reduction in capacity and stability of the material. In this study, nanocrystalline phase-pure LiNi0.5Mn1.5O4 was prepared by co-precipitation with cyclohexylamine followed by calcination at a low temperature of 500°C. X-ray diffraction studies confirmed that a highly crystalline face-centred cubic product is formed with F-d3m space group. Scanning electron microscopy and transmission electron microscope studies confirmed that the particles are in the nano range with a porous structure. The as-prepared LiNi0.5Mn1.5O4 showed a high initial specific capacity (up to 130 mA h g–1) and retained up to 120 mA h g–1 up to 50 cycles. The material has high conductivity and remains stable up to a 20-C discharge rate.

Synthesis and characterization of azo-guanidine based alcoholic media naked eye DNA sensor

DNA sensing always has an open meadow of curiosity for biotechnologists and other researchers. Recently, in this field, we have introduced an emerging class of molecules containing azo and guanidine functionalities. In this study, we have synthesized three new compounds (UA1, UA6 and UA7) for potential application in DNA sensing in alcoholic medium. The synthesized materials were characterized by elemental analysis, FTIR, UV-visible, 1H NMR and 13C NMR spectroscopies. Their DNA sensing potential were investigated by UV-visible spectroscopy. The insight of interaction with DNA was further investigated by electrochemical (cyclic voltammetry) and hydrodynamic (viscosity) studies. The results showed that compounds have moderate DNA binding properties, with the binding constants range being 7.2 × 103, 2.4 × 103 and 0.2 × 103 M−1, for UA1, UA6 and UA7, respectively. Upon binding with DNA, there was a change in colour (a blue shift in the λmax value) which was observable with a naked eye. These results indicated the potential of synthesized compounds as DNA sensors with detection limit 1.8, 5.8 and 4.0 ng µl−1 for UA1, UA6 and UA7, respectively.

Spectroscopic, Electrochemical, and In Silico Characterization of Complex Formed between 2-Ferrocenylbenzoic Acid and DNA

We present the synthesis of 2-ferrocenylbenzoic acid (FcOH) and its electrochemical and spectroscopic characterization. FcOH was characterized for interaction with DNA using theoretical and experimental methods. UV-visible spectroscopy and cyclic voltammeter (CV) were used for the experimental account of FcOH-DNA complex. The experimental results showed that the FcOH interacts by electrostatic mode. The binding constant () and Gibbs free energy () for the FcOH-DNA complex have been estimated as 5.3 × 104 M−1 and −6.44 kcal/mol, respectively. The theoretical DNA binding of FcOH was studied with AutoDock molecular docking software. The docking studies yield good approximation with experimental data and explain the sites of binding.