A new calix[6]azacryptand ligand has been prepared in six steps starting from 1,3,5-trismethoxycalix[6]arene. An X-ray study shows that this ligand has a sterically protected tren-based binding site at the bottom of a polyaromatic bowl and ether sites around its rim. It binds Zn(2+) to give a complex in which zinc is in a trigonal bipyramidal geometry with a water bound in one apical position a...

Nowadays, an accurate and precise description of the combustion phase is essential in spark-ignition (SI) engines to drastically reduce pollutant greenhouse gas (GHG) emissions increase thermal efficiency. To this end, computational fluid dynamics (CFD) can be used study different phenomena involved, such as ignition charge, development, formation. In work, a validation CFD methodology based on...

We study high-resolution central schemes in Lagrangian coordinates for the one-dimensional system of conservation laws describing the evolution of two gases in slab geometry separated by an interface. By using Lagrangian coordinates, the interface is transformed to a fixed coordinate in the computational domain and, as a consequence, the movement of the interface is obtained as a byproduct of t...

Heat transfer during compression of air in a long, thin tube is studied by CFD. The tube represents one of the many in a honeycomb geometry inserted in a liquid piston air compressor to minimize temperature rise. A dimensionless number for the heat flow rate that includes the changing heat transfer area between the tube wall and air during compression is used. From the CFD results, alinear rela...

Interactions between the surfaces of planar and nonplanar molecules have generated considerable interest in materials chemistry as critical elements for understanding twodimensional supramolecular assembly, molecular and chiral recognition, and heterogeneous catalysis. Carbon-rich balland bowl-shaped polyaromatic molecules, such as fullerenes and fullerene fragments or buckybowls, figure promin...

The aromaticity of all possible cyclopenta-fused pyrene congeners has been investigated at various levels of theory. On the basis of the calculated resonance energies and magnetic properties (delta(1)H data, magnetic susceptibility anisotropies, and NICS values), the overall aromaticity of these compounds is found to decrease gradually with increasing number of externally fused five-membered ri...

Complexes formed by anions and substituted molecular bowls were studied by means of computational methods. The bowls consisted of corannulene molecules substituted with five or ten F, Cl, or CN groups, whereas Cl(-), Br(-) and BF(4)(-) were the anions considered. Substitution with F, Cl and CN hardly affects the geometry of the bowl, but produces an inversion of the molecular electrostatic pote...