Search results for "bond"

A correlative IR, MS, 1H, 13C and 15N NMR and theoretical study of 4-arylthiazol-2(3H)-onesElectronic supplementary information (ESI) available: NMR …

2002

Sixteen 4-arylthiazol-2(3H)-ones (3) were synthesised by cyclisation of α-thiocyanatoacetophenones (1) in acid solution. They appear to prefer greatly the oxo tautomeric forms. In CCl4 solution an equilibrium between the free CO bond and a “dimeric” hydrogen-bonded form exists in which the latter predominates. Several IR and NMR (1H, 13C and 15N) spectral properties are shown to correlate with Hammett σ-values and/or atomic Mulliken charges and bond orders, the latter being estimated by PM3 or AM1 semiempirical methods. The electron-impact mass spectra were also recorded and the fragmentation mechanisms interpreted in terms of the energetics of the ionic species. In addition, the geometric …

ChemInform Abstract: Halogen-Bonded Supramolecular Complexes and Networks

2009

In spite of some controversy of the true nature of the interaction between polarized halogen atoms and neutral or charged Lewis bases, termed “halogen bonding”, as a primary interaction, it is a very useful new tool/way to construct supramolecular complexes and networks. This is especially true in solid state supramolecular chemistry where utilization of weak intermolecular interactions such as halogen bonding opens up new insights to materials design and supramolecular synthesis.

Alternative Motifs for Halogen Bonding (Eur. J. Org. Chem. 9/2013)

2013

N-{2-Methyl-5-[(5-oxo-10,11-dihydro-5H-dibenzo[a,d]cyclo­hepten-2-yl)amino]­phen­yl}benzamide

2010

In the title compound, C29H24N2O2, the two aromatic rings of the tricyclic unit are oriented at a dihedral angle of 32.27 (8)°. In the crystal N—H...O hydrogen bonds link the molecules into chains along the a axis. Further N—H...·O interactions link the chains.

N-{4-[(3-Methyl-phen-yl)sulfamo-yl]phen-yl}benzamide.

2011

In the title compound, C20H18N2O3S, the dihedral angle between the central benzene ring and the amide group is 24.1 (3)° and that between this ring and the aromatic ring of the tolyl group is 68.2 (16)°. In the crystal, adjacent molecules are linked by N—H...O hydrogen bonds into a linear chain running along [100]. Weak C—H...O contacts also occur. Extensive weak π–π interactions exist from both face-to-face and face-to-edge interactions occur between the aromatic rings [centroid–centroid distances = 3.612 (2) and 4.843 (2) Å].

Ab initio study of the tautomeric forms of some quinolinediones

1995

Abstract 7,8-dihydroquinoline-4,5 (1 H ,6 H )-dione ( 1 ) and 7,8-dihydroquinoline-2,5-(1 H ,6 H )-dione ( 2 ) in their tautomeric oxo and hydroxy forms have been studied by ab initio Hartree-Fock calculations; tautomerization energies predict a more stable hydroxy structure having an intramolecular hydrogen bond for compound 1, whereas the oxo form is slightly-preferred for compound 2. Fourier Transform-Infra Red (FT-IR) spectra in CHCl 3 solution indicate that the predicted most stable tautomers in the vapour phase remain as such.

3-(2,4-Dimethoxyanilino)-8-methoxydibenz[b,e]oxepin-11(6H)-one

2011

In the title compound, C23H21NO5, the two benzene rings of the tricyclic unit are oriented at a dihedral angle of 37.5 (8)°. The 2,4-dimethoxyanilino residue is oriented at a dihedral angle of 60.2 (8)° towards the phenoxy ring. In the crystal, the central carbonyl O atom accepts two hydrogen bonds from the N—H and C—H groups. A further intermolecular C—H...O interaction involving one of the methoxy O atoms is also observed.

Conformational equilibrium and intramolecular hydrogen bond of 4′X and 4X substituted 2′(OH)chalcones

1999

Abstract By using the AM1 method on 4X and 4′X substituted 2′(OH)chalcones (X=H, OH, F, Cl, CH 3 , CH 3 O, N(CH 3 ) 2 , and NO 2 ), certain currently unclear structural characteristics, conformational equilibria, intramolecular hydrogen bonds and UV spectroscopic properties had been clarified. The compounds studied have non-planar structures. The 2′(OH),4′Xchalcones only present the trans - s - cis conformation. trans - s - cis and trans - s - trans conformers of 2′(OH),4X-chalcones have a comparable thermodynamic stability. For these chalcones, a conformational equilibrium at 298 K exists, with 91% of the trans - s - cis form. The proposal of analyzing the intramolecular hydrogen bond of 2…

4-[3-(4-Fluorophenyl)quinoxalin-2-yl]-N-isopropylpyridin-2-amine

2009

In the crystal structure of the title compound, C22H19FN4, the quinoxaline system makes dihedral angles of 32.07 (13) and 69.64 (13)° with the 4-fluorophenyl and pyridine rings, respectively. The 4-fluorophenyl ring makes a dihedral angle of 71.77 (16)° with the pyridine ring. The crystal structure is stabilized by intermolecular N—H...N hydrogen bonding.

4-(4-Fluorophenyl)-1-(4-nitrophenyl)-3-(pyridin-4-yl)-1H-pyrazol-5-amine

2012

In the crystal structure of the title compound, C20H14FN5O2, the pyrazole ring forms dihedral angles of 59.3 (2), 25.6 (2) and 46.0 (2)° with the directly attached 4-fluorophenyl, pyridine and nitrophenyl rings, respectively. The crystal packing is characterized by intermolecular N—H...N and N—H...O hydrogen bonds.