Muhammad Khawar Rauf

Distribution of Natural Uranium in Surface and Groundwater Resources: A Review

Keeping in view the toxicity of uranium and to reduce exposure to uranium and avoid high doses, it is essential to examine on routine bases the concentration of natural radionuclide uranium (U) in surface and groundwater resources. In this approach, the concentrations of U (total U) were summarized in worldwide surface and groundwater resources. U(+6) is the major form of U in oxic surface waters, while U(+4) is the major form in anoxic waters. An efficient way of uranium measurement in all water sources must be utilized to obtain reliable results. For this purpose a summary of available analytical techniques for U determination has also been presented. On the basis of the available data, the chemical exposures from these contaminated water sources were specified and some important epidemiological cross-sectional, ecological, and case-control studies and influence of heavy metal mining on water quality were also included. The literature review results revealed that the concentrations of natural U are higher in many parts of the world than the prescribed limit of World Health Organization. Ground and surface water in different areas of the world is contaminated with U and available data is not enough regarding water-related diseases possibly due to the lack of diagnostic facilities. Regular surveys need to be conducted in various parts of the world to obtain a clear picture of water-linked diseases.

A one-pot multicomponent facile synthesis of dihydropyrimidin-2(1H)-thione derivatives using triphenylgermane as a catalyst and its binding pattern validation

A series of substituted dihydropyrimidin-2(1H)-thione derivatives (1–8) have been synthesized using a facile and modified procedure with triphenylgermyl propionate as a catalyst. In comparison with the classical Biginelli reaction, this new protocol has the advantages of excellent yield and shorter reaction times. The synthesized compounds have been characterized by various spectroscopic techniques such as FT-IR, multinuclear (1H/13C) NMR spectroscopy and single crystal XRD analysis. Molecular docking studies were performed to identify the probable binding modes of potent inhibitors in the active site of the enzymes human topoisomerase II alpha (4FM9) and Helicobacter pylori urease (1E9Y). Compound 3 was found to be the most potent inhibitor according to the molecular docking scores and molecular dynamic simulations which suggests it can be further processed as a lead molecule to interpret the pharmacological properties of these compounds.

Preliminary investigation of anticancer activity by determining the DNA binding and antioxidant potency of new ferrocene incorporated N,N',N″-trisubstituted phenylguanidines.

Six new bioactive ferrocene based phenylguanidines were successively synthesized and characterized by means of various analytical techniques like elemental analysis, FT-IR, multinuclear ((1)H and (13)C) NMR, UV-Vis spectroscopy and cyclic voltammetry. The interaction of compounds with DNA was investigated by spectroscopic and cyclic voltammetric measurements. The interaction was found to be the electrostatic and the binding constants values were impressively larger. Compounds f-1, f-2, f-3 have slight larger binding constant values ranging from 0.8×10(5) to 2.4×10(5) as compared to g-1, g-2 and g-3 ranging from 7.6×10(4) to 1.1×10(5) which is most probably due to the presence of ferrocene at para position where the delocalization of electrons is maximum. Antioxidant activity was determined by UV-Vis spectrophotometer by using DPPH as a free radical. All the compounds exhibit good antioxidant activity and the results so obtained support the structure activity relationship.

Novel approaches to screening guanidine derivatives

Introduction: Compounds containing guanidine moiety, originating both from natural and synthetic sources, have found potential applications in both synthetic and medicinal chemistry. Indeed, guanidine functionality can be found in many natural and pharmaceutical products as well as in cosmetic ingredients produced by synthetic methods. Areas covered: This review covers the latest developments in the research undertaken for the therapeutic application of newly synthesized guanidine derivatives including: small peptides and peptidomimetics. This article encompasses the selected literature published in the last three decades with a focus on the novel approaches for screening of lead drug candidates with their pharmacological action. Expert opinion: Guanidines, as they are both organically based and also hydrophilic in nature, have undergone a mammoth amount of screening and testing to discover promising lead structures with a CN3 core, appropriate for potential future drug development. The compounds have the potential to be neurodegenerative therapeutic options, as well as: anti-inflammatory, anti-protozoal, anti-HIV, chemotherapeutic, anti-diabetic agents and so on. It is true that guanidine-based compounds of natural sources also, like synthetic and virtually designed drugs, have been of significant interest and have the potential to be useful therapeutic options in the future. As for now, however, there is not sufficient data to support their use in a number of the suggested areas, and further studies are required.

Crystallographic structure and quantum chemical computations of 1-(3,4-dimethylphenyl)-3-phenyl-5-(4-methoxyphenyl)-2-pyrazoline.

In this study the experimental crystallographic structure and the calculated optimized geometric parameters, vibrational wavenumbers, (1)H NMR and (13)C NMR chemical shift values, electronic absorption maximum wavelength values, HOMO-LUMO analysis, and molecular electrostatic potential (MEP) of 1-(3,4-dimethylphenyl)-3-phenyl-5-(4-methoxyphenyl)-2-pyrazoline (in abbreviated 1h), molecule, (C24H24N2O), by using density functional theory (DFT/B3LYP) method with 6-311++G(d,p) basis set in the ground state have been reported for the first time. Furthermore the IR and Raman spectra of title molecule were simulated by using calculated vibrational results. Geometric parameters (bond lengths and bond angles) vibrational wavenumbers and (13)C &(1)H NMR chemical shift values for the mentioned compound calculated at B3LYP/6-311++G(d,p) level are in good agreement with the experimental data.

New supramolecular ferrocenyl phenylguanidines as potent antimicrobial and DNA-binding agents

Six new ferrocenyl phenylguanidines have been synthesized and characterized by elemental analysis, FT-IR, multinuclear (1H and 13C) NMR, and single crystal analysis. The latter showed a supramolecular structure for 2 mediated by O H and π H interactions. A subsequent DNA-binding study of these complexes proved them to be good DNA binders with the binding constant varying in the range of 1.2–5.6 × 105 M−1. These compounds were found to have moderate antibacterial and significant antifungal activities, especially for compounds having a chlorophenyl. These compounds may emerge as a new class of anticancer and antifungal agents alone or in combination with other drugs.

1-Benzoyl-3-(2,4,5-trichloro­phen­yl)thio­urea

The benzene and phenyl rings in the title compound, C14H9Cl3N2OS, form a dihedral angle of 40.98 (6)°. The molecule exists in the thione form with typical thiourea C—S [1.666 (2) Å] and C—O [1.227 (3) Å] bond lengths as well as shortened C—N bonds [1.345 (3) and 1.386 (2) Å]. An intramolecular N—H⋯O hydrogen bond stabilizes the molecular conformation. In the crystal, pairs of N—H⋯S hydrogen bonds link the molecules into centrosymmetric dimers.

Antileishmanial, DNA Interaction, and Docking Studies of Some Ferrocene‐Based Heteroleptic Pentavalent Antimonials

A series of ferrocenyl pentavalent antimonials (1–8) were synthesized and characterized by elemental analysis, FT‐IR, and multinuclear (1H and 13C) NMR spectroscopy. These antimonials were evaluated for their antileishmanial potential against Leishmania tropica KWH23, and by biocompatibility and membrane permeability assays. Moreover, mechanistic studies were carried out, mediated by DNA targeting followed by computational docking of ferrocenyl antimonials against the leishmanial trypanothione reductase enzyme. It was observed that the antimonials 1–8 were 390‐fold more efficacious (IC50) as compared with the standard antimonial drug used. Cytotoxicity results showed that these antimonials are highly active even at low concentrations and are biocompatible with human macrophages. Antimonials 1–8 exhibited extensive intercalation with DNA and, furthermore, docking interactions highlighted the potential interactive binding of the anitimonials within the trypanothione reductase active site, with van der Waals interactions contributing significantly to the process. Hence, it is suggested that the reported antimonials demonstrate high efficacy, less toxicity, and target multiple sites of the Leishmania parasite.

Synthesis and crystal structure studies of three n-phenylphthalimide derivatives

The three N-phenylphthalimide derivatives, 2-(3,4-dichlorophenyl)isoindoline-1,3-dione (I), 2-(2,4-dichlorophenyl)isoindoline-1,3-dione (II) and 2-(2,4,5-trichlorophenyl)isoindoline-1,3-dione (III), were synthesized by the condensation of equimolar amounts of phthalic anhydride and 3,4-dichloroaniline, 2,4-dichloroaniline, 2,4,5-trichloroaniline, respectively, under acetic acid reflux and their structures determined by a combination of elemental analysis, FT-IR, 1H & 13C-NMR spectroscopy and single crystal X-ray diffraction studies. Compounds I and II crystallize in a monoclinic crystal system (space group P21/c) with cell parameters of a = 5.7414(2), b = 8.0917(6), c = 26.077(1) Å and β = 99.4709(12)o for compound I, and a = 12.7133(9), b = 13.4328(9), c = 7.2603(5) Å and β= 93.210 (2)o for compound II. On the other hand, compound III crystallizes in a tetragonal crystal system (space group I41/a) with a = 13.4607(9) and c = 30.100(2) Å. The phthalimide moieties of these compounds are essentially planar, while the chloro-substituted phenyl ring of each compound shows consistent twist from the phthalimide plane with dihedral angles of 61.02(3), 69.09(3) and 85.78(5)o, respectively, for I, II and III. In the crystal structures of these compounds, a few weak C–H···O interactions form double-tape structures of centrosymmetric dimers of graph-set notation R22(10) for I and III, and an inversion dimer of graph-set motif R22(14) for II. In addition, some short contacts of C···C, C···O and Cl···Cl are observed for I, II and III, respectively.Graphical AbstractThis paper presents the synthesis, characterization and structural studies of three derivatives of Phthalimides which are well known cytotoxic DNA intercalating agents and potential anti-cancer agents, inhibit the acute inflammatory response and HIV-1 reverse transcriptases and found usefulness in OLEDs. Compounds I and II crystallize in a monoclinic crystal system (space group P21/c) while compound III crystallizes in a tetragonal crystal system (space group I41/a). The phthalimide moieties of these compounds are essentially planar, while the chloro-substituted phenyl ring of each compound shows consistent twist from the phthalimide plane. A few weak C–H···O interactions form double-tape structures for I and III, and a dimer for II.

Temperature-controlled Deposition of Copper(I) Oxide and Metallic Copper Nanostructures from Single-source Molecular Precursor

A simple method of depositing morphology- and phase-tailored thin films of copper(i) oxide and metallic copper from [Cu(dmae)(TFA)]4·CH2Cl2 (1), where dmae is N,N-dimethylaminoethanolato and TFA is trifluoroacetato, on glass substrates by aerosol-assisted chemical vapour deposition is demonstrated. The tetrameric precursor 1 was synthesized and its structure was determined by single-crystal X-ray crystallography. Precursor 1 was applied for the deposition of nanostructured thin films of copper(i) oxide and copper nanowires at 250 and 375°C respectively. The deposited thin films were characterized by powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray diffraction, and ultraviolet–visible spectroscopy. The results indicate that the phase and morphology of the deposited material are strongly dependent on deposition temperature. UV-vis studies reveal that copper(i) oxide films with a band gap of 2.48 eV may find possible applications in tandem photoelectrochemical devices as light-absorbing material.