the interaction of dppa which is an important component in cellular membrane with molecules of water asmedia, cause some changes in geometry of dppa .in this study we focused our attention on comparing thismolecule with related hydrated complexes employing different basis sets at hartree-fock levels of theory. thetheoretical nmr shielding tensor of some imported atoms were also reported.

The hydrogen bond is the most important of all directional intermolecular interactions. It is operative in determining molecular conformation, molecular aggregation, and the function of a vast number of chemical systems ranging from inorganic to biological. Research into hydrogen bonds experienced a stagnant period in the 1980s, but re-opened around 1990, and has been in rapid development since...

2,5,10,13-tetraazatricyclo [12,2,2,26,9] icosa-1(16),6,8,14,17,19-hexene-3,4,11,12-tetraone tetraoxime (1a) and 2,5,11,14-tetraazatricyclo [13,3,1,16,10] icosa-1(19),6,8,10(20),15,17-hexaene-3,4,12,13-tetraonetetraoxime (1b) were obtained from condensation of 1,4- and 1,3-phenylendiamine with dichloroglyoxime, respectively. the reaction of 1,2-phenylendiamine with dichloroglyoxime resulted in t...

The hydrogen-bond-acceptor (HBA) templates 2,3-bis(4-methylenethiopyridyl)naphthalene (2,3-nap) and 1,8-bis(4-pyridyl)naphthalene (1,8-dpn) are used to assemble (E,E)-2,5-dimethylmuconic acid (dmma) in the solid state for an intermolecular [2 + 2] photocycloaddition. Co-crystallisation of 2,3-nap with dmma affords an 1D hydrogen-bonded polymer that is photostable while 1,8-nap affords a 0D hydr...

The mol-ecule of the title compound, C(12)H(15)N(3)O(2)S, which belongs to the family of thio-semicarbazones, containing an acid group, adopts a semi-closed conformation with an intramolecular N-H⋯N hydrogen bond. In the crystal, molecules are linked by strong N-H⋯O and O-H⋯S hydrogen bonds between the acid group and thiosemicarbazone unit, with one additional intermolecular hydrogen C-H⋯O inte...

The absolute stereochemistry of the title compound, C(9)H(15)NO(7), was determined from the use of d-glucuronolactone as the starting material. The compound crystallizes as the zwitterion. The five-membered ring adopts an envelope conformation with the -CH(2)OH-substituted C atom forming the flap. An intramolecular N-H⋯O hydrogen-bond occurs. In the crystal, the compound exists as a three-dimen...

In the title compound, C(11)H(11)NO(4), the asymmetric unit contains two unique mol-ecules, both of which are almost planar, with r.m.s. deviations of 0.047 and 0.059 Å. The dihedral angles between the benzene ring and the plane of maleamic acid unit are 3.43 (5) and 5.79 (3)° in the two mol-ecules. The mol-ecular structures are stabilized by a short intra-molecular O-H⋯O hydrogen bond within e...

2,5,10,13-Tetraazatricyclo [12,2,2,26,9] icosa-1(16),6,8,14,17,19-hexene-3,4,11,12-tetraone tetraoxime (1a) and 2,5,11,14-tetraazatricyclo [13,3,1,16,10] icosa-1(19),6,8,10(20),15,17-hexaene-3,4,12,13-tetraonetetraoxime (1b) were obtained from condensation of 1,4- and 1,3-phenylendiamine with dichloroglyoxime, respectively. The reaction of 1,2-phenylendiamine with dich...

Geometries and interaction energies of unusual UU and AA base pairs with one standard hydrogen bond (H-bond) and additional C-H...O or C-H...N contacts have been determined by quantum-chemical methods taking into account electron correlation. Whereas the C-H bond length in the UU C-H...O contact increases upon complex formation (H-bond pattern), the C-H bond of the AA C-H....N interaction is sh...