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    Crystallographic Studies of Dehydration Phenomenon in Methyl 3-hydroxy-2-methyl-1,1,4-trioxo-1,2,3,4-tetrahydro-1λ 6-benzo[e][1,2]thiazine-3-carboxylate
    (Springer/Plenum Publishers, 2013) Arshad, Muhammad Nadeem; Sahin, Onur; Zia-ur-Rehman, Muhammad; Shafiq, Muhammad; Khan, Islam Ullah; Asiri, Abdullah M.; Khan, Sher Bahadar
    Methyl 3-hydroxy-2-methyl-1,1,4-trioxo-1,2,3,4-tetrahydro-1 lambda(6)-benzo[e][1,2]thiazine-3-carboxylate was synthesized in single step through in situ bromination of methyl 2-methyl-1,1,4-trioxo-1,2,3,4-tetrahydro-1 lambda(6)-benzo[e][1,2]thiazine-3-carboxylate using dibenzoyl peroxide & N-bromosuccinamide and was crystallized in acetone-ethyl acetate mixture (1:1). However, crystallization in methanol converted the title compound to methyl 3-methoxy-2-methyl-1,1,4-trioxo-1,2,3,4-tetrahydro-1 lambda(6)-benzo[e][1,2]thiazine-3-carboxylate, an unsymmetrical ether. The titled compound C11H11NO6S (3) crystallized in nonoclinic space group P2(1)/c whereas, the compound C12H13NO6S (4) crystallized in triclinic space group P-1. X-ray studies shows that the molecules of 1 are linked into a one-dimensional framework structure by C-H center dot center dot center dot O and O-H center dot center dot center dot O hydrogen bonds, while in 4, intermolecular C-H center dot center dot center dot O and C-H center dot center dot center dot pi hydrogen bonds and a pi center dot center dot center dot pi interaction result in the formation of infinite chains running along the [010] and [001] directions.
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    Facile Synthesis and Crystal Structures of New Ammonium Sulfonates (CA-DNBS and TEA-TMBS)
    (Chinese Journal Structural Chemistry, 2013) Khan, Islam Ullah; Arshad, Muhammad Nadeem; Sahin, Onur; Mubashar-Ur-Rehman, Hafiz; Munir, Ayesha; Humayun, Saba; Asiri, Abdullah M.
    The title compounds, C12H10N3O7SCl (I) and C15H27NO3S (II), crystallize in the monoclinic system, space group P2(1)/c with a = 7.3995(1), b = 27.8489(6), c = 9.8246(2) angstrom, beta = 131.349(1)degrees, V = 1519.82(5) angstrom(3), Z = 4, F(000) = 768, R-int = 0.033 and S = 1.03 for I, and in the orthorhombic system, space group Pbca with a = 8.6227(1), b = 16.1480(4), c = 23.8774(6) angstrom, V = 3324.67(12) angstrom(3), Z = 8, F(000) = 1312, R-int = 0.024 and S = 1.04 for II. We have devised a convenient procedure for the synthesis of fused organic salts resulting from 1:1 proton-transfer, using an amine and a derivative of benzenesulfonic acid. The synthesized salts have a number of applications ranging from their consumption as eco-friendly solvents and catalysts in organic syntheses, to being used as efficient precursors for the production of sulfa drugs. Structures of compounds 3-chloroanilinium 2,4-dinitrobenzenesulfonate (CA-DNBS) and triethylaminium 2,4,6-trimethylbenzenesulfonate (TEA-TMBS) were determined by single-crystal X-ray diffraction studies and infrared spectroscopy.
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    Molecular structure, spectroscopic and quantum chemical studies of 1′,3′,3′-trimethylspiro[benzo[f]chromene-3,2′-indoline
    (Elsevier, 2016) Asiri, Abdullah M.; Ersanli, Cem Cuneyt; Sahin, Onur; Arshad, Muhammad Nadeem; Hameed, Salem A.
    In this work, synthesis, X-ray single crystal determination, nuclear magnetic resonance (H-1 NMR and C-13 NMR), Ultraviolet-Visible (UV-vis), Fourier transform infrared spectroscopy (FT-IR) and quantum mechanical studies of the 1',3',3'-trimethylspiro[benzo[f]chromene-3,2'-indoline [(C23H21NO), TMSBCI] have been both experimentally and theoretically reported. The molecular structure obtained from X-ray single-crystal analysis of the investigated compound in the ground state has been compared using Hartree-Fock (HF) and density functional theory (DFF) with the functional B3LYP using the 6-31G(d,p) as basis set. In addition to the optimized geometrical structures, atomic charges, molecular electrostatic potential (MEP) and natural bond orbital (NBO) have been investigated by using B3LYP/6-31G(d,p) level of the theoretical approximation for the title compound. The energetic behavior of TMSBCI has been examined in solvent media using polarizable continuum model (PCM). The total dipole moment (mu), the average linear polarizability (alpha), and the first-order hyperpolarisability (beta) values of the investigated molecule have been computed using the same method. The experimental measurements (H-1 NMR, C-13 NMR and UV vis) have been compared with its corresponding the calculated values (using DFT). Besides, frontier molecular orbitals (FMOs) and thermodynamic properties have also been studied. (C) 2016 Elsevier B.V. All rights reserved.
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    Synthesis and description of intermolecular interactions in new sulfonamide derivatives of tranexamic acid
    (Elsevier, 2016) Ashfaq, Muhammad; Arshad, Muhammad Nadeem; Danish, Muhammad; Asiri, Abdullah M.; Khatoon, Sadia; Mustafa, Ghulam; Zolotarev, Pavel N.
    Tranexamic acid (4-aminomethyl-cyclohexanecarboxylic acid) was reacted with sulfonyl chlorides to produce structurally related four sulfonamide derivatives using simple and environmental friendly method to check out their three-dimensional behavior and van der Walls interactions. The molecules were crystallized in different possibilities, as it is/after alkylation at its O and N atoms/along with a co-molecule. All molecules were crystallized in monoclinic crystal system with space group P2(1)/n, P2(1)/c and P2(1)/a. X-ray studies reveal that the molecules stabilized themselves by different kinds of hydrogen bonding interactions. The molecules are getting connected through O-H center dot center dot center dot O hydrogen bonds to form inversion dimers which are further connected through N-H center dot center dot center dot O interactions. The molecules in which N and 0 atoms were alkylated showed non-classical interaction and generated centro-symmetric R-2(2)(24) ring motif. The co-crystallized host and guest molecules are connected to each other via O-H center dot center dot center dot O interactions to generate different ring motifs. By means of the ToposPro software an analysis of the topologies of underlying nets that correspond to molecular packings and hydrogen-bonded networks in structures under consideration was carried out. (C) 2015 Elsevier B.V. All rights reserved.
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    Synthesis, spectral analysis, X-ray crystal structures and evaluation of chemical reactivity of five new benzoindazole derivatives through experimental and theoretical studies
    (Elsevier, 2014) Taib, Layla A.; Faidallah, Hassan M.; Sahin, Zarife Sibel; Asiri, Abdullah M.; Sahin, Onur; Arshad, Muhammad Nadeem
    The main purpose of this study was synthesis, X-ray, DFT and spectroscopic investigations of the title compounds (I-V). Five new compounds were synthesized and the detailed experimental results are reported. The crystal and molecular structures of the title compounds have been determined by IR, H-1 NMR, C-13 NMR and single-crystal X-ray diffraction. Molecular geometries from X-ray experiment of I-V in the ground state have been compared using the Density Functional Theory (DFT) with B3LYP/6-31G(d,p) basis set. In addition, the molecular electrostatic potential maps and frontier molecular orbitals were performed at B3LYP/6-31G(d,p) level of theory. DFT global chemical reactivity descriptors (chemical hardness, total energy, electronic chemical potential and electrophilicity) are calculated for the title molecules and used to predict their relative stability and reactivity. (C) 2014 Elsevier B.V. All rights reserved.