Interactions classified as intermolecular resonance assisted hydrogen bonds (RAHBs) are analyzed here. Hence the MP2/6-311++G(d,p) calculations for dimers of formic, acetic and pyrrole-2carboxylic acid (PCA) were performed. The similar calculations were carried out for formamide and its fluorine derivatives’ dimers as well as the tautomeric forms of the latter species. The Quantum theory of Ato...

Scalar fields provide an intuitive picture of chemical bonding. In particular, the electron localization function (ELF) has proven to be highly valuable in interpreting a broad range of bonding patterns. The discrimination between enhanced or reduced electron (de)localization within cyclic π-conjugated systems remains, however, challenging for ELF. In order to clearly distinguish between the lo...

The title mol-ecule, C(12)H(6)Cl(2)N(2), is almost planar (the r.m.s. deviation of C atoms is 0.04 Å). The C-N and C-C distances indicate delocalization of the π-electrons in the aromatic fused-ring system.

The cation of the title salt, C(34)H(45)N(2) (+)·PF(6) (-), is a protonated form of an unsymmetrical overcrowded β-imino-amine. The observed bond lengths [C-N = 1.326 (4)-1.341 (4) Å and C-C = 1.383 (4)-1.391 (4) Å] suggest significant delocalization within the π system of the N C C C N backbone.

The title compound, C(9)H(8)O(4)S, affords a zigzig chain in the crystal structure by inter-molecular O-H⋯O hydrogen bonds. The molecular geometry suggests that extensive but not uniform π-electron delocalization is present in the benzene ring and extends over the exocyclic C-S and C-C bonds.

Electrical conductivity of organic semiconductor materials represents one of the critical parameters that control the performance efficiency of organic-based electronic and optoelectronic devices. For materials assembled from planar aromatic molecules, evidence suggests that charge carrier mobility is usually maximized along the direction of cofacial π-π stacking of the molecules.1-3 While such...

The title compound, C(9)H(8)N(4)O(3)S, shows a layer structure constructed from inter-molecular O-H⋯O and O-H⋯N hydrogen bonds. Inter-atomic distances suggest that extensive, but not uniform, π-electron delocalization is present in the tetra-zole rings and extends over the exocyclic C-S bond.

The title mol-ecule, C(9)H(8)BrNO, approximates a full planar conformation. The inter-planar angle between the benzene and five-membered rings of the indoline system is 1.38 (1)°. There is an obvious π-delocalization involving the N-C=O group in the five-membered ring, which is greater than that involving the N-C C(benzene) group.

The concept of Resonance Assisted Hydrogen Bond (RAHB), which usually occurs in b diketons, has a remarkable role in chemistry. These molecules, which contain heteroatom particularly O and N, are species with biological interest in protein folding and DNA pairing. Therefore, the amplification of hydrogen bonds strength by substituents may be important in life scie...