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    Öğe
    4-hydroxy-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide-oxalohydrazide (1:1): X-ray structure and DFT calculations
    (Pleiades Publishing Inc, 2013) Arshad, M. N.; Sahin, O.; Zia-ur-Rehman, M.; Khan, I. U.; Asiri, A. M.; Rafique, H. M.
    The title compound, 4-hydroxy-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide-oxalohydrazide (1:1), is determined using X-ray diffraction techniques and the molecular structure is also optimized at the B3LYP/6-31G(d,p) level using density functional theory (DFT). The asymmetric unit consists of four independent molecules. The oxalohydrazide molecules have the centre of symmetry at the mid-point of the central C-C bond. Each thiazine ring adopts a half-chair conformation. Intermolecular C-H...O, N-H...O and N-H...N hydrogen bonds produce R (2) (2) (10), R (2) (2) (13), R (3) (3) (12) and R (3) (3) (15) rings, which lead to one-dimensional polymeric chains. An extensive three-dimensional supramolecular network of N-H...N, N-H...O, C-H...O and O-H...O hydrogen bonds is responsible for crystal structure stabilization.
  • [ X ]
    Öğe
    Lanthanide Complexes with Pyridine-2,6-Dicarboxylic Acid: Synthesis, Crystal Structure, Thermal and Magnetic Properties of [LnPDA)2(PDAH2)] • (DMAH2)2(DMAH0.5)2
    (Pleiades Publishing Inc, 2016) Sharif, S.; Khan, B.; Sahin, O.; Khan, I. U.
    Mild solvothermal synthesis, structures, thermal and magnetic properties of coordination complexes [Ln(PDA)(2)(PDAH(2))] center dot (DMAH(2))(2)(DMAH(0.5))(2)(I-IV) (PDA = pyrdine-2,6-dicarboxylate anion, DMAH = dimethylamine, Ln = Ce, Nd, Sm, and Ho) are described. The DMAH molecules in I-IV, generated in situ from hydrolysis of N,N-dimethylformamide, are responsible to assemble three dimensional coordination polymers through N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds. Distorted tricapped trigonal prismatic LnO(6)N(3) geometry having 14 triangular faces is attributed to mean deviation of dihedral angles while nitrogen shows fairly triangular faces having dihedral angle close to 60 degrees C (CIF files CCDC nos. 872065 (I), 872070 (II), 872069 (III), and 872066 (IV)). Curie-Weiss law and the overall magnetic behavior are typical for the presence of antiferromagnetic exchange coupling interactions between lanthanide. Thermal decomposition analyses reveal removal of ammonia and resultant complexes showthermal stability. Complexes have been further characterized by using elemental analyzer and FT-IR spectroscopy.