Monte Carlo study of the conformation-dependent hydration of the 18-crown-6 macrocycle

Interfacial Behavior of Ionophoric Systems: Molecular Dynamics Studies on 18-Crown-6 and Its Complexes at the Water-Chloroform Interface

“…2), these crowns displayed dihedral angles which are reminiscent of those of the D 3d and C i forms. Based on Monte Carlo 27 and MD simulations 28 , it was predicted that the D 3d form would be stabilized and the most populated form in bulk water. At the interface, we notice that all molecules which remained in contact with the aqueous phase remained D 3d and sol- …”

“…c. Corresponds to the "extracted" 18C6·K + complex (see text and vated by bridging water molecules on one face, as in bulk water. 27 Figure 2 shows that in the plane of the interface, water makes hydrogen bond networks, which are all connected to ether oxygens of the D 3d solutes. Thus, despite its zero dipole moment, the D 3d form displays some amphiphilic character, and asymmetrical surrounding by solvent at the interface.…”

“…1,6,23 The 18C6 molecule, which is one of the cornerstones of supramolecular chemistry 1,3,5 , has been the target of most of the computer simulation methods. After the first molecular mechanics studies of 18C6 free and complexed in the gas phase 24 , its conformational state has been investigated by MD (molecular dynamics) or Monte Carlo simulations, in the gas phase 25,26 and in polar solutions like water 27,28 , acetonitrile 29 , or the pure liquid phase 30 as well as in apolar solvents. 31 The question of ion binding selectivity in solution has also been extensively explored by MD techniques.…”

The hydration structure of 18-crown-6/K+ complex as studied by Monte Carlo simulation using ab initio fitted potential

“…In addition, ligand's solvation leads also to a clearer understanding of the macrocyclic effect, of the extra stability of the complexes between the metal ions and macrocyclic ligand in comparison to those of their open-chain analogues. It was found that the D 3d conformation of 18-crown-6 is the most favorable in aqueous solution [4][5][6]. Experimental studies [7,8] suggest that such conformation is also preserved when the 18-crown-6/K + complex is formed in aqueous solution.…”

Studies of molecular interactions in aqueous and CCl4 solutions involving 18-crown-6 by application of Kirkwood–Buff theory

“…These are due to their ability to form well-defined host-guest type complexes with neutral guest molecules as well as with several metal ions in different solvents. Amongst the various crown ethers, 18-crown-6 (treated as a model compound) has been extensively studied theoretically as well as experimentally due its higher symmetry and complete solubility in water [4][5][6][7][8][9][10][11][12]. The studies of hydrophobic hydration and interaction phenomena are of immense value in understanding biological processes which include salting-in and salting-out effects, protein unfolding and specific binding equilibrias [13,14].…”