Haq Nawaz Sheikh

Sonochemical synthesis of a novel nanorod diaqua(pyridine-2,6-dicarboxylato)copper(II) 3-D supramolecular network: new precursor to prepare pure phase nanosized copper(II) oxide

A nanosized copper(II) supramolecular compound, [Cu(dipic)(H2O)2] n (1) [dipic = 2,6-pyridinedicarboxylate], has been synthesized by sonochemical method and characterized by elemental analysis, scanning electron microscopy, X-ray powder diffraction, IR spectroscopy, TGA/DTA, and BET surface area studies. The structure of single crystalline 1 developed from nanosized 1 has been determined by X-ray crystallography and further characterized by scanning electron microscopy, TGA/DTA, and BET surface area studies. The XRD studies reveal that nanorod copper(II) supramolecular compound adopts a 3-D supramolecular network owing to extensive hydrogen-bonding and π–π stacking. Solvent effects on size and morphology of nanosized 1 have been studied. Calcination of nanosized 1 at 500°C under air yields CuO nanoparticles.

Synthesis and characterization of some oxodiperoxo molybdenum(VI) complexes of Morpholinomethyl urea and related ligands

The oxodiperoxo complexes of Mo(VI) of the type [MoO(O2)2L], where L = Morpholinomethyl urea, morpholinomethyl thiourea, piperidinomethyl urea, piperidinomethyl thiourea, pyrrolidinomethyl urea, and pyrrolidinomethyl thiourea have been synthesized and characterized by elemental analysis, molar conductance, IR, UV-Vis, and TGA/DTA techniques. It is shown that the ligands coordinate to the metal ion in a symmetrical bidentate fashion through heterocyclic nitrogen and carbonyl oxygen or thiocarbonyl sulfur. Thermal studies indicate continuous weight loss until a stable oxide is formed.

Lanthanide-based entangled coordination polymers connected by thiophene-2,5-dicarboxylate: solvothermal syntheses, crystal structures, luminescence and magnetic properties

Nine novel coordination polymers (CPs) with the formulas [M6(TDA)9(DEF)5(H2O)3]n [M = Ce (1), Pr (2), Nd (3), Sm (4)], [Eu4(TDA)6(DEF)3(H2O)2]n (5), [Gd2(TDA)3(DEF)2]n·H2O (6), [Tb2(TDA)3(DEF)2]n·0.5H2O (7), [Dy2(TDA)3(DEF)2]n·H2O (8) and [Yb2(TDA)3(DEF)2]n·0.5H2O (9) (TDA = 2,5-thiophenedicarboxylate anion and DEF = diethylformamide) have been synthesized at different temperatures in a DEF–H2O solvent system under solvothermal conditions. All the compounds were characterized by single crystal X-ray diffraction analysis (XRD), Fourier transformation vibrational spectroscopy (FT-IR) and thermal analysis (TGA). Structural analyses of CPs 1–4 reveal that the polymers crystallize in the orthorhombic space group Pna21 and form 3D frameworks with large volumes 10 378.1(5), 10 230.5(5), 10 171.9(5) and 10 077.1(11) A3, respectively. The M(III) ions of CPs 1–4 exhibit nine and eight coordination numbers with diverse geometries. Structural analyses of CPs 5 and 6–9 unveil that the polymers crystallize in the monoclinic system, with space groups P21 and P2/c, respectively, forming a 3D network. The TDA ligand exhibits two coordination modes [(κ1-κ1)–(κ1-κ1)-μ4 and (κ2-κ1-μ2)–(κ1-κ1)-μ5] which interconnect the metal ions to generate 3D novel metal–organic frameworks. The luminescence properties of 4, 5, 7 and 8, and the magnetic properties of 6–8 were investigated.

Room temperature aqueous phase synthesis and characterization of novel nano-sized coordination polymers composed of copper(II), nickel(II), and zinc(II) metal ions with p-phenylenediamine (PPD) as the bridging ligand

Nanostructured metal-organic hybrid materials composed of nickel(II), copper(II), and zinc(II) metal ions and p-phenylenediamine (PPD) as the organic ligand were synthesized in aqueous medium at room temperature. The synthesized compounds were characterized by elemental analyses, powder X-ray diffraction (PXRD) spectra, Fourier transform infrared spectra, nuclear magnetic resonance (1H NMR) spectra, electronic spectra, scanning electron microscopy, N2 adsorption-desorption isotherm, and dynamic light scattering studies. N2 adsorption-desorption isotherm of copper(II)-PPD compound confirmed that it has mesoporous structure as it exhibits type-IV reversible isotherm with H1 hysterisis. Steep adsorption indicated that the mesopores possessing it are of uniform order. Barrett-Joyner-Halenda model showed an average pore diameter of 5.2 nm. The PXRD patterns of all the three compounds are identical and showed well-defined and highly intense diffraction peaks, thereby suggesting their nature as crystalline. The broadness of the diffraction peaks indicated that the particles are of nanometer dimensions.

Synthesis and characterization of oxodiperoxo complexes of tungsten(VI) with some Mannich base ligands

Six oxodiperoxotungsten(VI) complexes, [WO(O2)2L–L] (where L–L = morpholinobenzyl benzamide (MBB), piperidinobenzyl benzamide (PBB), piperidinobenzyl urea (PBU), morpholinobenzyl urea (MBU), piperidinobenzyl thiourea (PBTU) and morpholinobenzyl thiourea (MBTU)) have been prepared by stirring WO3 · H2O with excess 30% aqueous (w/v) H2O2 and then treating with an ethanolic solution of the Mannich base ligand (L–L). These have been characterized by elemental analysis, conductance and magnetic susceptibility measurements, IR spectra, electronic spectra, 1H NMR, TGA/DTA and cyclic voltammetric studies. These complexes are non-electrolytes and diamagnetic in nature. The ligands are bound to metal in a bidentate mode through carbonyl oxygen/thiocarbonyl sulphur and the ring nitrogen. The complexes also inhibit the growth of pathogen “Fusarium Spp.” up to 60%. The cyclic voltammograms of the complexes indicate quasi-reversible redox steps involving complexes.

Facile hydrothermal synthesis of nanocomposites of nitrogen doped graphene with metal molybdates (NG-MMoO4) (M=Mn, Co, and Ni) for enhanced photodegradation of methylene blue

A facile one-pot hydrothermal synthesis of nanocomposites of nitrogen doped graphene with MnMoO4/CoMoO4/NiMoO4 is reported. The morphological and structural characteristics of prepared NG-MMoO4 nanocomposites have been characterized by Powder X-ray diffraction, Fourier transform vibrational spectroscopy, Scanning electron microscopy, Transmission electron microscopy and Thermal analysis. The molybdates are well-anchored and uniformly distributed on the surface of nitrogen doped graphene sheets. The nanocomposites exhibit excellent photocatalytic activity as demonstrated by photodegradation of methylene blue under Ultraviolet–Visible irradiation by using NG-MnMoO4 as catalyst.

Synthesis, crystal structure, photoluminescence, and DFT studies of bis(1,10-phenanthroline)di(κ2OO′ nitrato)cadmium(II) [Cd(phen)2(NO3)2]

A cadmium 1,10-phenanthroline complex, [Cd(phen)2(NO3)2] has been synthesized by and its crystal structure determined. The compound is monoclinic, C2/c, a=11.5008(2), b=15.3523(2), c=13.2767(2)Å, β=103.610(2), Z=4. The compound is monomeric with a octacoordinate cadmium ion bonded to two bidentate 1,10-phenanthroline molecules and two bidentate nitrate units. The metal ion is bis-chelated by two N-heterocycles as well as by two nitrate ions in a distorted dodecahedral CdN4O4 coordination environment. The complex is thermally stable up to 110°C. Photophysical investigation reveals that complex is luminescent in the solid state. The molecular geometry, harmonic vibrational frequencies and bonding features of complex [Cd(phen)2(NO3)2] in the ground-state have been calculated by using the density functional B3LYP method with 3-21G (d, p) as higher basis set. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. Finally the calculation results were applied to simulate infrared spectrum of the title compound which show good agreement with observed spectrum.

Hydrothermal synthesis, characterization and luminescent properties of lanthanide-doped NaLaF4 nanoparticles

Nanoparticles of sodium lanthanum (III) fluoride-doped and co-doped with Eu3+/Tb3+ were prepared by the hydrothermal method using citric acid as structure-directing agent. Structural aspects and optical properties of synthesized nanoparticles were studied by powder X-ray diffraction (XRPD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive X-ray spectra (EDS), particle size by dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectrum and photoluminescence (PL) techniques. Nanoparticles consist of well-crystallized hexagonal phase and the average crystallite size for undoped and doped-NaLaF4 nanoparticles are in the range of 20–22 nm. TEM images show that nanoparticles have cylindrical shape and crystalline nature of nanoparticles was confirmed by SAED patterns. Down- conversion (DC) luminescent properties of doped NaLaF4 were also investigated and impact of co-doping has been explored.

Peroxo complexes of uranium(VI) containing nitrogen and oxygen donor ligands

The uranium(VI) peroxo complexes containing Mannich base ligands having composition [UO(O2)L-L(NO3)2] {where L-L = morpholinobenzyl acetamide (MBA), piperidinobenzyl acetamide (PBA), morpholinobenzyl benzamide (MBB), piperidinobenzyl benzamide (PBB), morpholinomethyl benzamide (MMB), piperidinomethyl benzamide (PMB), morpholinobenzyl formamide (MBF)}, piperidinobenzyl formamide (PBF) are reported. In a typical reaction UO2(NO3)2 · 6H2O (1 mmol, 0.502 g) was dissolved in methanol. An equimolar (1 mmol) methanolic solution (30 mL) of the ligand (Mannich bases) was added to a solution of uranyl nitrate followed by addition of potassium hydroxide (KOH) (2 mmol, 0.1122 g). The solution was refluxed for 15 min and then 10 mL of 30% hydrogen peroxide (H2O2) was added dropwise and was refluxed for an additional 1 h. The synthesized complexes have been characterized by various physico-chemical techniques, viz. elemental analysis, molar conductivity, magnetic susceptibility measurements, infra red, electronic, mass spectral and TGA/DTA studies. These studies revealed that the synthesized complexes are non-electrolytic and diamagnetic in nature. The ligands are bound to metal in a bidentate mode through carbonyl oxygen and the ring nitrogen. Thermal analysis result provides conclusive evidence for the absence of water molecule in the complexes. Mass spectra confirm the molecular mass of the complexes. Antibacterial activity of complexes revealed enhanced activity of complexes as compared to corresponding free ligands. Molecular modeling suggests pentagonal bipyramidal structure for complexes.

Synthesis and characterization of peroxo complexes of uranium(VI) with some Mannich base ligands

Uranium(VI) peroxo complexes of composition [UO(O2)L–L(NO3)2], where L–L are the Mannich base ligands morpholinobenzyl urea, piperidinobenzyl urea, morpholinobenzyl thiourea, piperidinobenzyl thiourea, morpholinomethyl thiourea, piperidinomethyl thiourea, or morpholinomethyl urea, are reported. The synthesized complexes were characterized by use of a variety of physicochemical techniques, viz. elemental analysis, molar conductivity, magnetic susceptibility measurements, IR, electronic, mass, 1H NMR, and 13C NMR spectroscopy, and TGA/DTA studies. These studies revealed that the complexes are both non-electrolytic and diamagnetic in nature. The ligands are bound to the metal in a bidentate mode through carbonyl oxygen or thiocarbonyl sulfur and the ring nitrogen. Mass spectra confirm the molecular mass of the complexes. The antifungal activity of the complexes is greater than that of the corresponding free ligands.Graphical Abstract