In the title compound, C13H9N3O5, the mean plane of the non-H atoms of the central amide fragment C-N-C(=O)-C [r.m.s. deviation = 0.0442 Å] forms dihedral angles of 71.76 (6) and 24.29 (10)° with the C-bonded and N-bonded benzene rings, respectively. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds forming C(4) chains along [100]. Weak C-H⋯O contacts link the mol-ecules into (100) ...

Nitrogen 1s (N 1s) core-to-Rydberg excitation spectra of hydrogen-bonded clusters of ammonia (AM) have been studied in the small cluster regime of beam conditions with time-of-flight (TOF) fragment-mass spectroscopy. By monitoring partial-ion-yield spectra of cluster-origin products, "cluster" specific excitation spectra could be recorded. Comparison of the "cluster" band with "monomer" band re...

We optimized the geometries of the graphene and graphene with hydrogen using PW91VWN, PWCIPL,MPWLYP, G96LYP, G96141.0-210.6-310, 6-31G*Ievels of theory and compared our results with each other.We present the most important structural parameters determined for the addition of a hydrogen atom tographene and the outward movement of the carbon atom that is bonded to hydrogen is 0.48 A Also wecalcul...

The configuration of the C=N double bond of the title compound, C(7)H(6)BrNO, is E; the non-H atoms are approximately coplanar (r.m.s. deviation = 0.038 Å). In the crystal, pairs of mol-ecules are linked by a pair of O-H⋯N hydrogen bonds about a center of inversion, generating hydrogen-bonded dimers.

The secondary interaction contribution in complexation via multiple hydrogen bonds was estimated using model complexes. Based on the results of hydrogen fluoride complexes, proton donor (D) proton acceptor (A) type secondary interaction was attractive, and the total stabilization energy should be increased about 2535%, based on hydrogen bond interaction, by the D-A type secondary interaction. T...

PRECISE (Predicted and Consensus Interaction Sites in Enzymes) is a database of interactions between the amino acid residues of an enzyme and its ligands (substrate and transition state analogs, cofactors, inhibitors and products). It is available online at http://precise.bu.edu/. In the current version, all information on interactions is extracted from the enzyme-ligand complexes in the Protei...

The non-H atoms of the title mol-ecule, C(14)H(16)N(4)OS, are coplanar, with an r.m.s. deviation of 0.039 Å. The dihedral angle between the two aromatic rings is 2.4 (2)°. An intra-molecular C-H⋯O hydrogen bond is observed. The mol-ecules exist as N-H⋯N hydrogen-bonded centrosymmetric dimers.

An empirically based relationship between overall complex stability (-DeltaG degrees ) and various possible component interactions is developed to probe the question of whether the A.T/U and G.C base-pairs exhibit enhanced stability relative to similarly hydrogen-bonded complexes. This phenomenological approach suggests ca. 2-2.5 kcal mol-1 in additional stability for A.T owing to a group inter...

The asymmetric unit of the title mol-ecular salt, [C5H7N2+][(HO)2OP(CH2)9PO2(OH)-], consists of one 4-amino-pyridinium cation and one hydrogen (9-phos-phono-non-yl)phospho-nate anion, both in general positions. As expected, the 4-amino-pyridinium moieties are protonated exclusively at their endocyclic nitro-gen atom due to a mesomeric stabilization by the imine form which would not be given in ...