46 research outputs found
Host-guest and guest-guest interactions between xylene isomers confined in the MIL-47(V) pore system
The porous MIL-47 material shows a selective adsorption behavior for para-, ortho-, and meta-isomers of xylenes, making the material a serious candidate for separation applications. The origin of the selectivity lies in the differences in interactions (energetic) and confining (entropic). This paper investigates the xylene-framework interactions and the xylene-xylene interactions with quantum mechanical calculations, using a dispersion-corrected density functional and periodic boundary conditions to describe the crystal. First, the strength and geometrical characteristics of the optimal xylene-xylene interactions are quantified by studying the pure and mixed pairs in gas phase. An extended set of initial structures is created and optimized to sample as many relative orientations and distances as possible. Next, the pairs are brought in the pores of MIL-47. The interaction with the terephthalic linkers and other xylenes increases the stacking energy in gas phase (-31.7 kJ/mol per pair) by roughly a factor four in the fully loaded state (-58.3 kJ/mol per xylene). Our decomposition of the adsorption energy shows various trends in the contributing xylene-xylene interactions. The absence of a significant difference in energetics between the isomers indicates that entropic effects must be mainly responsible for the separation behavior
Influence of the electric field on supramolecular structure and properties of amyloid-specific reagent Congo red
The effects of water on the morphology and the swelling behavior of sulfonated poly(ether ether ketone) films
Energy decomposition analysis of cation-π, metal ion-lone pair, hydrogen bonded, charge-assisted hydrogen bonded, and π-π interactions
Aromatic Borozene
Based on our comprehensive theoretical investigation and known experimental
results for small boron clusters, we predict the existence of a novel aromatic
inorganic molecule, B12H6. This molecule, which we refer to as borozene, has
remarkably similar properties to the well-known benzene. Borozene is planar,
possesses a large first excitation energy, D3h symmetry, and more importantly
is aromatic. Furthermore, the calculated anisotropy of the magnetic
susceptibility of borozene is three times larger in absolute value than for
benzene. Finally, we can show that borozene molecules may be fused together to
give larger aromatic compounds with even larger anisotropic susceptibilities.Comment: 4 pages, 4 figures and 1 tabl
Parallel Interactions of Aromatic Molecules at Large Horizontal Displacements
Parallel interactions at large horizontal displacements of aromatic rings with water and with other aromatic rings are presented. The geometries and energies of interactions were studied by analyzing crystal structures from the Cambridge Structural Database (CSD) and structures of proteins and by quantum chemical calculations. © 2016 John Wiley & Sons, Inc