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  • 1
    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Structural characteristics ofS-phenylo-chlorothiobenzoate (I) andS-phenylo-bromothiobenzoate (II) have been investigated by single crystal X-ray diffraction. It was shown that the crystals are isomorphous and crystallize in the monoclinic space groupP21 withZ=2. The unit cell parameters are:a=10.150(3),b=7.672(2),c=7.595(2) Å,β=91.28(1)° for C13H9ClOS (compoundI) anda=10.141(3),b=7.764(2),c=7.653(2) Å,β=90.14(3)° for C13H9BrOS (compoundII). The structures were solved by heavy-atom methods and refined by full-matrix least-squares, from room-temperature data collected with a Philips PW 1100 diifractometer, to conventionalR factors of 0.056 forI and 0.044 forII. The structures consist of independent molecules held together by intermolecular interactions. Molecular packing is influenced by the presence ofo-substituted Cl or Br atoms. The Cl atoms in structureI as well as the Br ones in structureII are directed to the centers of the pi-electronic system of theo-substituted phenyl rings belonging to the neighboring molecules. The six Cl⋯C and Br⋯C distances range from 3.651(10) to 3.869(9) Å and from 3.644(6) to 3.890(6) Å, respectively. The C1 (or Br) atom is additionally directed towards the two carbon atoms (C3 and C4) in anothero-substituted phenyl ring, the C1⋯lC and Br⋯C distances being 3.786(9) and 3.849(10) Å inI and 3.727(6) and 3.881(6) Å inII. The torsion angle C6-C7-S-C8 is-170.2(7)° inI and 168.6(4)° inII. The angles between the planar O-C7-S central fragment of the molecule, on the one hand, and theo-substituted phenyl ring, on the other, are 113.9(3)° in I and 110.9(2)° inII. The corresponding values for the angles between the O-C7-S fragment and the nonsubstituted phenyl ring are 115.8(3)° and 114.3(2)° in compoundsI andII, respectively.
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  • 2
    ISSN: 1572-8854
    Keywords: Lactone-hydrochloride ; solid-state structure ; X-ray diffraction ; conformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The X-ray crystal structure of (R,S)-α-amino-γ-caprolactone hydrochloride (compound1) and α-amino-γ-methyl-γ-valerolactone hydrochloride semihydrate (compound2) are presented. Both compound1 and compound2 belong to the orthorhombic system. Caprolactone-hydrochloride1 crystallizes in the space groupP212121 witha=5.1948(7),b=8.7404(8),c=17.907(1) Å.V=813.0(2) Å3,Z=4. Valerolactone-hydrochloride2 crystallizes in the space groupP na21 witha=26.771(8),b=5.1598(7),c=13.201(3) Å,V=1823.5(7) Å3,Z=8. The lactone cations maintain the same, open envelope conformation in both crystals. The lactone-hydrochloride packing arrangements in1 and2 are distinctly different. While in1 N−H...Cl and N−H...O hydrogen bonding creates two dimensional nets in the form of puckered layers perpendicular to the [001] direction, in2 a water molecule of crystallization with an additional OW−H...Cl hydrogen interaction assists in forming a three-dimensional hydrogen-bond network throughout the crystal.
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  • 3
    ISSN: 1572-8854
    Keywords: Planar Schiff base ligands ; intramolecular N−H...O hydrogen bond ; quinoid effect ; X-ray crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The structures of N-(α-naphthyl)-2-oxy-1-naphthaldimine1 and N-(β-naphthyl)-2-oxy-1-naphthaldimine2 have been investigated by X-ray analysis and by spectroscopic methods. Crystals of1 are monoclinic, space groupPn, with cell dimensionsa=10.823(3),b=5.826(2),c=11.899 (3) Å, and β=99.66(3)°. Compound2 crystallizes in the orthorhombic space groupPca21 witha=17.564(3),b=6.314(2), andc=13.663(4) Å. The IR spectra exhibited neither N−H nor O−H stretching frequencies. The existence of theintramolecular hydrogen bonding of N−H...O type was predicted by spectroscopic experiment but unequivocally established by diffraction experiment in both cases1 and2. The molecules1 and2 are significantly planar with considerable quinoid effect at the 2-oxy-naphthaldimine moiety. Although essentially planar, both molecules1 and2 show the delocalization of π-electrons only in the central part of the molecules including C=N imino group with pendent ring carbon atoms.Intermolecular attractions in the crystals belong to weak van der Waals interactions-between discrete planar molecules spatially arranged into the expectedherringbone motif in the solid state.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical crystallography 28 (1998), S. 77-82 
    ISSN: 1572-8854
    Keywords: N-aryl naphthaldimines ; conformational changes ; keto-enol tautomerism ; stepped conformation ; X-ray molecular and crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The main scope of the paper deals with keto/amine-enol/imine tautomerism in the solid state of an N-aryl substituted naphthaldimine and conformational changes of this ligand after coordinating to the nickel atom. The N-o-tolyl-2-hydroxy-1-naphthaldimine (I) crystallizes in the orthorhombic space group P 212121 with cell dimensions a = 7.8641(4), b = 12.712(1), c = 13.853(1) Å and corresponding bis-bidentate nickel complex (II) in the monoclinic space group P 21/c and unit cell dimensions a = 7.436(3), b = 22.050(5), c = 8.643(4) Å, β = 95.05(6)°. In the nonplanar molecule of (I) the presence of the enol tautomer is found. In (II) the metal atom has the characteristic square-planar coordination with NiII on crystallographically imposed inversion centers. Two naphthaldimine moieties are not coplanar showing stepped conformation with step height 1.034 Å.
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