Mazhar Amjad Gilani

Synthesis, crystal structure, spectroscopic and density functional theory (DFT) study of N-[3-anthracen-9-yl-1-(4-bromo-phenyl)-allylidene]-N-benzenesulfonohydrazine

N-[3-anthracen-9-yl-1-(4-bromo-phenyl)-allylidene]-N-benzenesulfonohydrazine has been synthesized and characterized by various spectroscopic techniques including FT-IR, UV-vis, (1)H-NMR, (13)C-NMR spectroscopy, and the structure was unequivocally confirmed by single crystal X-ray diffraction studies. The compound crystallized in monoclinic system with P21/n space group, and adopted cis-geometry around the azomethine CN double bond. The X-ray crystal structure revealed that the intermolecular packing was stabilized by C-H⋯O type hydrogen bonding interaction, whereas NH was not involved in hydrogen bonding due to steric hindrance. Absorption wavelength was studied by scanning UV-vis. absorption spectrum in different solvents to explore excited state stability of the molecule in polar solvent. Density functional theory calculations were performed at B3LYP/6-31G (d, p) level in order to compare the experimental results with the theoretical results. The simulated molecular electrostatic potential (MEP), Mulliken charges and NPA (natural population analysis) also confirmed the presence of specific intermolecular hydrogen bonding (C-H⋯O). In addition natural bond orbital (NBO) analysis (intra and inter molecular bonding and interaction among bonds), frontier molecular orbital analysis (electronic properties) and first hyperpolarizability analysis (nonlinear optical response) were simulated at B3LYP/6-31G (d, p) level of theory.

Characteristic Properties of Nanoclays and Characterization of Nanoparticulates and Nanocomposites

Clays have been one of the more important industrial minerals; and with the recent advent of nanotechnology, they have found multifarious applications and in each application, nanoclays help to improve the quality of product, economize on the cost and saves environment. The chapter describes key characteristics of nanoclays and their classification on the basis of the arrangement of “sheets” in their basic structural unit “layer”. Major groups include kaolin–serpentine, pyrophyllite-talc, smectite, vermiculite, mica and Chlorite. The structural, morphological and physicochemical properties of halloystite and montmorillonite nanoclays, representative of the 1:1 and 2:1 layer groups, respectively, are discussed as well. After briefly introducing the surface modification of clay minerals by modifying or functionalizing their surfaces and their incorporation into polymer matrices to develop polymer/clay nanocomposites, techniques that are being employed to characterize these nanoclays, in general, and the sample preparation for these techniques, in particular, are also reviewed in this chapter.

Organocatalyzed solvent free an efficient novel synthesis of 2,4,5-trisubstituted imidazoles for α-glucosidase inhibition to treat diabetes.

A new and efficient solvent free synthesis of 2,4,5-trisubstituted imidazoles (3a-3j) was achieved by N-acetyl glycine (NAG) catalyzed three components condensation of aldehydes, benzil and ammonium acetate. Our synthetic methodology accommodated a range of various substituted alkyl and aryl aldehydes. Evaluation of α-glucosidase inhibitory activity of these imidazole derivatives revealed that most of them presented good α-glucosidase inhibition at low micro-molar concentrations. Among the synthesized compounds, compound 3c, bearing the ortho-hydroxy phenyl substituent at position 2 displayed the highest inhibitory activity with an IC50 value 74.32±0.59 μM. In silico molecular docking for all compounds and computational studies of the most active compound 3c were also performed.

Isolation, spectroscopic and density functional theory studies of 7-(4-methoxyphenyl)-9H-furo[2,3-f]chromen-9-one: a new flavonoid from the bark of Millettia ovalifolia.

The phytochemical examination of chloroform soluble fraction (FX2) of methanolic extract of bark of Millettia ovalifolia yielded a new flavonoid; 7-(4-methoxyphenyl)-9H-furo [2,3-f]chromen-9-one (1). Compound 1 is characterized by spectroscopic analytical techniques such as UV, IR, 1D, 2D NMR spectroscopy, and mass spectrometry. A theoretical model is also developed for obtaining geometric, electronic and spectroscopic properties of 1. The geometry optimization and harmonic vibration simulations have been carried out at B3LYP/6-31G(d,p). The vibrational spectrum of compound 1 shows nice correlation with the experimental IR spectrum, through a scaling factor of 0.9613. (1)H and (13)C NMR chemical shifts are simulated using Cramers re-parameterized function WP04 at 6-31G(d,p) basis set, and correlate nicely with the experimental chemical shifts.

Synthesis and structural properties of 2-((10-alkyl-10H-phenothiazin-3-yl)methylene)malononitrile derivatives; a combined experimental and theoretical insight

BackgroundDonor acceptor moieties connected through π-conjugated bridges i.e. D-π-A, in order to facilitate the electron/charge transfer phenomenon, have wide range of applications. Many classes of organic compounds, such as cyanine, coumarin carbazole, indoline, perylene, phenothiazine, triphenylamine, tetrahydroquinoline and pyrrole can act as charge transfer materials. Phenothiazines have been extensively studied as electron donor candidates due to their potential applications as electrochemical, photovoltaic, photo-physical and DSSC materials.ResultsTwo phenothiazine derivatives, 2-((10-hexyl-10H-phenothiazin-3-yl)methylene)malononitrile (3a) and 2-((10-octyl-10H-phenothiazin-3-yl)methylene)malononitrile (3b) have been synthesized in good yields and characterized by various spectroscopic techniques like FT-IR, UV–vis, 1H-NMR, 13C-NMR, and finally confirmed by single crystal X-ray diffraction studies. Density functional theory (DFT) calculations have been performed to compare the theoretical results with the experimental and to probe structural properties. In order to investigate the excited state stabilities the absorption studies have been carried out experimentally as well as theoretically.ConclusionsCompound 3a crystallises as monoclinic, P2 (1)/a and 3b as P-1. The X-ray crystal structures reveal that asymmetric unit contains one independent molecule in 3a, whereas 3b exhibits a very interesting behavior in having a higher Z value of 8 and four independent molecules in its asymmetric unit. The molecular electrostatic potential (MEP) mapped over the entire stabilized geometries of the molecules indicates the potential sites for chemical reactivities. Furthermore, high first hyperpolarizability values entitle these compounds as potential candidates in photonic applications.Graphical abstractPhenothiazines; a comparison of experimental and theoretical analysis

Dyotropic rearrangement of bridgehead substituents in closed dithienylethenes; conjugated verses non-conjugated analogues

Type I dyotropic rearrangement reactions of halogen and methyl substituents at the bridgehead position of diarylethenes and dihydroarylethenes have been studied through density functional theory at B3LYP/6-31+G(d) level. The calculations have been performed to explore the dyotropic rearrangement as a possible factor for the elusive nature of halogenated dithienylethenes (closed). The dyotropic rearrangement process in closed dithienylethenes is then compared with the dihydro analogues. Moreover, the effect of hetero atom and conjugation is also explored through quantum mechanical calculations.

Efficient drug delivery system for bone repair by tuning the surface of hydroxyapatite particles

A limited blood flow to skeletal tissues results in minimal therapeutic effect of drugs being administered to a patient using conventional ways. To obtain sufficient amount of drug at an effected site, implanted drug delivery systems based on biomaterials can be used. In this study, surface modified hydroxyapatites (m-HA) were prepared and evaluated as drug delivery systems. The effect of modifiers on surface properties of HA and their in vitro drug delivery efficiency were investigated. For synthesis of m-HA, a simple in situ co-precipitation method was used. Hydroxyapatite was subjected to surface modification by various carboxylic acids such as adipic acid, malonic acid, succinic acid and stearic acid. This surface modification affected its surface properties such as surface area, pore size, pore volume, particle size and crystallinity. The m-HA were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Brunauer–Emmett–Teller (BET) technique was used to compute surface properties of m-HA. The highest BET surface area of 143 m2 g−1 has been found for HA modified with malonic acid and the lowest surface area of 37 m2 g−1 was calculated for stearic acid modified HA. The BET adsorption average pore size (17–20 nm) of m-HA confirmed its mesoporous nature. The biocompatible nature of the prepared m-HA was assessed by 3-(4,5)-dimethylthiahiazo(-z-yl)-3,5-di-phenytetrazoliumromide (MTT) assay. To evaluate the influence of functional groups and surface properties of m-HA on drug delivery efficiency, ibuprofen was used as a model drug. In vitro drug delivery experimental results indicated that drug loading and release efficiency relied on functional groups, surface area, and porosity of m-HA. The percentage loading of ibuprofen was good for samples containing free –COOH groups and high surface area. A drug loading of 22 mg g−1 has been found for malonic acid modified HA (ma-HA) having high surface area, pore volume, whereas a poor loading of 2.03 mg g−1 has been observed for stearic acid modified HA (st-HA) sample having low surface area and pore volume. A sustained drug release profile showed that 61% drug had been released from malonic acid modified HA (ma-HA) in 24 hours. A 100% drug release was observed for st-HA in 8 hours. Succinic acid modified HA and adipic acid modified HA exhibited intermediate drug release profiles. The drug release behavior of m-HA followed Ficks laws of diffusion.

Synthesis and DPPH scavenging assay of reserpine analogues, computational studies and in silico docking studies in AChE and BChE responsible for Alzheimer's disease

Alzheimers disease (AD) is a fast growing neurodegenerative disorder of the central nervous system and anti-oxidants can be used to help suppress the oxidative stress caused by the free radicals that are responsible for AD. A series of selected synthetic indole derivatives were biologically evaluated to identify potent new antioxidants. Most of the evaluated compounds showed significant to modest antioxidant properties (IC50 value 399.07 140.0±50 µM). Density Functional Theory (DFT) studies were carried out on the compounds and their corresponding free radicals. Differences in the energy of the parent compounds and their corresponding free radicals provided a good justification for the trend found in their IC50 values. In silico, docking of compounds into the proteins acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), which are well known for contributing in AD disease, was also performed to predict anti-AD potential.