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Classical Hydrogen Bonds (classical + hydrogen_bond)
Selected AbstractsSolid-State Structure and Tautomerism of 2-Aminotroponimines Studied by X-ray Crystallography and Multinuclear NMR SpectroscopyEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2004Rosa M. Claramunt Abstract Structural studies in the solid state by X-ray crystallography and by 13C and 15N CPMAS NMR spectroscopy carried out on a series of 2-aminotroponimine derivatives 2,5 has allowed to establish the existence of hydrogen bonding and to determine the most stable tautomer. Almost all the structures reflect the classical double-well potential function for the N,H···N hydrogen bonds. Only in the case of the compound N -(pyrrol-1-yl)-2-(pyrrol-1-ylamino)troponimine (5) the crystal structure shows two independent molecules, one with a classical hydrogen bond and another with either a single-well or a low-barrier hydrogen bond. The structure of this compound is discussed with the use of the solid-state NMR spectroscopic data. 2-Aminotropones, as intermediates to the 2-aminotroponimines, show the oxo-tautomer as the stable form. B3LYP/6-31G* calculations are used to rationalise the experimental results. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] A tetrazol-5-yl analogue of glycine, 5-ammoniomethyl-1H -tetrazolide, and its copper(II) complexACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2010Alexander S. Lyakhov A nonclassical tetrazole isostere of glycine, viz. zwitterionic 5-ammoniomethyl-1H -tetrazolide, C2H5N5, (I), crystallizes in the chiral P31 space group, similar to ,-glycine. The crystal packing of (I) is determined by a set of classical hydrogen bonds, forming a three-dimensional network that is practically the same as that in ,-glycine. The CuII complex of (I), poly[[bis(,2 -5-aminomethyl-1H -tetrazolido-,3N1,N5:N4)copper(II)] dihydrate], {[Cu(C2H4N5)2]·2H2O}n, (II), is a layered coordination polymer formed as a result of tetrazole ring bridges. The CuII cations lie on inversion centres, are surrounded by four anions and adopt elongated octahedral coordination. Water molecules are located in the interlayer space and connect the layers into a three-dimensional network via a system of hydrogen bonds. [source] Novel chalcones derived from 2-chloro-3-formyl-6-methylquinolineACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2008Umar Farooq Rizvi Molecules of (E)-3-(2-chloro-6-methylquinolin-3-yl)-1-(5-iodo-2-thienyl)prop-2-en-1-one, C17H11ClINOS, (I), and (E)-3-(2-chloro-6-methylquinolin-3-yl)-1-(5-methyl-2-furyl)prop-2-en-1-one, C18H14ClNO2, (II), adopt conformations slightly twisted from coplanarity. Both structures are devoid of classical hydrogen bonds. However, nonclassical C,H...O/N interactions [with C...O = 3.146,(5),Å and C...N = 3.487,(3),Å] link the molecules into chains extended along the b axis in (I) and form dimers with an R22(8) motif in (II). The structural analysis of these compounds provides an insight into the correlation between molecular structures and intermolecular interactions in compounds for drug development. [source] 4-Benzoyloxy-2-methyl- N -(2-pyridyl)-2H -1,2-benzothiazine-3-carboxamide 1,1-dioxideACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2006Natalia N. Pankrushina The crystal structure of the title compound, C22H17N3O5S, contains dimers linked by N,H,O hydrogen bonds about inversion centers. The dimers are packed in a herring-bone framework without classical hydrogen bonds between the structure-forming units. Supplement Material This is for the supplement Material content [source] | ||||||||||