Aneela Anwar

Synthesis, spectral characterization and antibacterial studies of palladium(II) complexes of heterocyclic thiones

Reactions of K2[PdCl4] with heterocyclic thiones in molar ratios of 1:2 and 1:4 in water-methanol medium yielded the palladium(II) complexes with the general formula of either [Pd(L)Cl2], [Pd(L)2]Cl2 or [Pd(L)4]Cl2 where L ═ Imidazolidine-2-thione (Imt), 2-Mercaptopyridine (Mpy), 2-Mercaptopyrimidine (Mpm), 6-Mercaptopurine (6-Mp) and Thionicotinamide (Tna). The complexes were characterized by elemental analysis and spectroscopic (IR, 1H and 13C NMR) methods. An upfield shift in the >C═S resonance of thiones in 13C NMR and downfield shift in N–H or aromatic proton resonances in 1H NMR are consistent with the sulfur coordination to palladium(II). The complexes were screened for antibacterial activity, and the results showed that the complexes exhibited moderate activities as compared to that of a standard drug.

Electrochemical determination of folic acid: A short review

Folic acid (FA) is an electroactive compound of biological origin. It helps our body to produce and maintain healthy cells. It can significantly reduce the occurrence of neural tube defects and also prevents change in DNA structure. FA deficiency can lead to various health risks. Therefore, a sensitive, specific, and reproducible way of FA detection is essential. A number of analytical methods are in practice for the quantification of FA. However, electroanalytical methods are attracting much attention because of their advantage over conventional methods, as they are fast, simple, sensitive, and cost effective. Moreover, modification of electrodes offers control over size and morphology which allows miniaturization for applicability in portable electrochemical devices.

Phytantriol based smart nano-carriers for drug delivery applications

ABSTRACT From the last couple of decades, lyotropic liquid crystals have garnered enormous attentions in medical and pharmaceutical sciences. Non‐toxic, chemically stable, and biocompatible properties of these liquid crystal systems are contributing to their applications for drug delivery. Among a large variety of liquid crystal phases, inverse bicontinuous cubic and inverse hexagonal mesophases have been extensively investigated for their ability to encapsulate and controlled release of bioactive molecules of various sizes and polarity. The concept of changing the drug release rate in situ by simply changing the mesophase structure is much more fascinating. The encapsulation of bioactive compounds in mesophase systems of desirable features in sub‐micron sized particles such as hexosomes and cubosomes, at ambient and high temperature is bringing innovation in the development of new drug applications. This review article outlines unique structural features of cubosomes and hexosomes, their methods of productions, factors affecting their formations and their potential utilization as smart nano‐carriers for biopharmaceuticals in drug delivery applications. Graphical abstract Model representation of inverse hexagonal (HII) and inverse bicontinuous cubic (QIID) liquid crystalline phases. Figure. No Caption available.

Synthesis and characterization of pure and nanosized hydroxyapatite bioceramics

Abstract Synthetic nanosized hydroxyapatite (HA) particles (<120 nm) were prepared using a co-precipitation technique by adopting two different routes – one from an aqueous solution of calcium nitrate tetrahydrate and diammonium hydrogen phosphate at pH 10 and the other by using calcium hydroxide and phosphoric acid as precursors at pH 8.5 and reaction temperature of 50°C. The lattice parameters of HA nanopowder were analogous to reference [Joint Committee on Powdered Diffraction Standards (JCPDS)] pattern no. 09-432. No decomposition of HA into other phases was observed even after heating at 1000°C in air for 1 h. This observation revealed the high-temperature stability of the HA nanopowder obtained using co-precipitation route. The effects of preliminary Ca/P molar ratio, precipitation, pH and temperature on the evolution of phase and crystallinity of the nanopowder were systematically examined and optimized. The product was evaluated by techniques such as X-ray-diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and Raman spectroscopy analyses. The chemical structural analysis of the as-prepared HA sample was performed using X-ray photoelectron spectroscopy (XPS). After heat treatment at 1000°C for 1 h and ageing for 15 h, the product was obtained as a phase-pure, highly crystalline HA nanorods.

SYNTHESIS, CRYSTAL STRUCTURE, AND ANTIMICROBIAL STUDIES OF TRANS-[PD(PPH3)2(IMIDAZOLIDINE-2-THIONE)2]CL2 · 3.5H2O

The palladium(II) complex, [Pd(PPh3)2(Imt)2]Cl2 · 3.5H2O (I) (Imt = imidazolidine-2-thione), has been synthesized and characterized by IR, NMR, and X-ray crystallography. An upfield shift in the >C=S resonance of Imt in the 13C NMR spectrum and a downfield shift in the N-H resonance in 1H NMR are consistent with the sulfur coordination of Imt to palladium(II). In the crystal structure of I, the central palladium atom is coordinated to two thione sulfur atoms of Imt and to two phosphorus atoms possessing a square-planar environment with the average cis and trans bond angles of 89.60° and 167.31°, respectively. The title complex was screened for antimicrobial effects, and the results showed that it exhibits moderate activities against gram-negative bacteria (E. coli, P. aeruginosa). The complexes also exhibited significant activities against yeast (C. albicans, S. serevisaiae).

Platinum as an electrocatalyst: effect of morphological aspects of Pt/Pt-based materials

ABSTRACT Platinum and platinum-based materials with high catalytic performance, and chemical and mechanical stability are vital to electronic devices, biomedical science, optics, petroleum, and automotive industries. Because of the limited supply and high cost of platinum, it is highly desirable to develop new effective methodologies which can decrease the platinum loading by increasing its electrocatalytic properties. Depending upon their size, shape, and morphology, platinum materials have shown significant improvement in the surface catalysed chemical transformation pathways in fuel cell technology. Much research is now focused on the manufacturing and engineering of platinum and platinum-based materials which proffer enhanced catalytic efficiency, and offer chemical and mechanical robustness.

Synthesis and crystal structures of bis(imidazolidine-2-thione-κS)bis(thiocyanato-κS)mercury(II) and bis(cyanido)bis(μ2-imidazolidine-2-thione-κS)mercury(II).Hg(CN)2

Abstract Two mercury(II) complexes containing imidazolidine-2-thione (Imt) and thiocyanate or cyanide ligands, [Hg(Imt)2(SCN)2] (1) and [Hg(Imt)2(CN)2].Hg(CN)2 (2), have been prepared and characterized by IR and NMR spectroscopy and X-ray crystallography. In compound 1, the mercury atom is located on a two-fold rotation axis and is coordinated to two thione sulfur atoms of imidazolidine-2-thione (Imt) and to two sulfur atoms of thiocyanate in a distorted tetrahedral mode with the S-Hg-S bond angles in the range of 98.96(3)–148.65(6)°. In 2, the mercury atom is hexa-coordinated having a distorted octahedral geometry composed of two cyanide C atoms [Hg-C=2.055(5) Å] and four weakly bound thione S atoms of imidazolidine-2-thione (Imt) [Hg-S=3.1301(13) and 3.1280(13) Å]. One free Hg(CN)2 molecule is also present in the crystal. In both complexes, the molecular structure is stabilized by N-H…N and N-H…S hydrogen bonding interactions.

Enhanced supercapacitive performance of cost-effectively synthesized ZnO-reduced graphene oxide composite

Commercially accessible and long-lasting resources of energy are among the foremost areas of current research. Supercapacitors have taken the position of very thoughtful candidates in the energy-storing field to meet the modern necessities. Several graphene-based materials have been employed for supercapacitor electrodes. Here, we demonstrated an economical and advanced hydrothermal technique using combination of two reducing materials (urea and starch) for the fabrication of reduced graphene oxide/zinc oxide (RGO/ZnO) composite. The X-ray diffraction and scanning electron microscopy analysis were carried out to study the structure and of RGO/ZnO composite. The supercapacitive behaviour of RGO/ZnO composite was studied via cyclic voltammetry and galvanostatic charge/discharge experiments. The results showed enhanced specific capacitance (313.14 F g−1) with good cyclic stability (1000 cycles).