Block-localized wave function (BLW) method, which is a variant of the ab initio valence bond (VB) theory, was employed to explore the nature of resonance-assisted hydrogen bonds (RAHBs) and to investigate the mechanism of synergistic interplay between pi delocalization and hydrogen-bonding interactions. We examined the dimers of formic acid, formamide, 4-pyrimidinone, 2-pyridinone, 2-hydroxpyri...

An organocatalytic strategy for the synthesis of tetrasubstituted pyrrolidines with monoactivated azomethine ylides in high enantiomeric excess and excellent exo/endo selectivity is presented. The key to success is the intramolecular activation via hydrogen bonding through an o-hydroxy group, which allows the dipolar cycloaddition to take place in the presence of azomethine ylides bearing only ...

We compare the self-assembly of the various isomers of benzene-dicarboxylic acids at the interface between solution and graphite substrate. In the case of planar benzene-dicarboxylic acids it was possible to observe long-range ordered monolayers by STM. However, no ordered adsorption was observed for the nonplanar 1,2-benzene-dicarboxylic acid. By means of a control experiment with 1,2,4,5-benz...

We have designed a new set of D-π-A type organic dye sensitizers with different acceptor and anchoring groups, and systematically investigated their optoelectronic properties for efficient dye sensitized solar cell applications. Particularly, we have focused on the effects of anchoring groups on the dye aggregation phenomenon. TDDFT results indicate that the dyes with CSSH anchoring groups exhi...

In the mol-ecule of the title compound, C(16)H(14)O(5), all non-H atoms are approximately co-planar [maximum atomic deviation = 0.064 (5) Å]. The hy-droxy group is a hydrogen-bond donor to a carbonyl O atom. Weak intermolecular C-H⋯O hydrogen bonding is present in the crystal structure. The crystal structure is 'whole-mol-ecule disordered' about an axis that runs approximately along the length ...

In the title compound, C(25)H(22)Cl(2)N(2)O(4)·CH(3)OH, the macrocyclic mol-ecule adopts a slightly distorted C(2)-symmetric conformation. The macrocyclic mol-ecules are linked via N-H⋯O hydrogen bonds between the amide groups into chains extending along the [010] direction. The methanol mol-ecules bridge these chains via N-H⋯O and O-H⋯O hydrogen bonds with the formation of a two-dimensional po...

The title compound [alternatively called (2-bromo-phen-yl)-(hydr-oxy)acetonitrile], C(8)H(6)BrNO, is the reaction product of 2-bromo-benzaldehyde and hydrogen cyanide. Bond lengths and angles are normal. In the crystal structure, an intermolecular hydrogen bond between the hydr-oxy group and the nitrile N atom is established. In agreement with bonding considerations, a linear C-N⋯H acceptor geo...

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...

This paper is a density functional theory (DFT) calculation of intramolecular proton transfer (IPT) in 6-hydroxypicolinic acid (6HPA, 6-hydroxypyridine-2-carboxylic acid) tautomeric forms. The transition state for the enol-to-keto transition is reported in the gas phase and in four different solvents. The planar and non-planar dimer forms of 6HPA keto and enol, respectively, were also studied i...

The structural, vibrational, and energetic properties of adducts of alkanes and strong cationic proton donors were studied with composite ab initio calculations. Hydrogen bonding in D-H(+)...H-alkyl adducts contributes to a significant degree to the interactions between the two components, which is substantiated by NBO and AIM results. The hydrogen bonds manifest themselves in the same manner a...