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

Interfacial Activity of the Diprotonated 222 Cryptand at the Water/"Oil" Interface Revealed by Molecular Dynamics Simulations

“…This approach considers a sphere of cutoff radius immersed in a polarizable dielectric continuum. We previously found that such simulation conditions lead to similar interface properties as those obtained with 30-Ewald summation [17]. The 1-4 electrostatic interactions in 222 2 + and in Picwere scaled down by a factor of 2.0.…”

“…This led to the" computer discovery" of the interfacial activity of extractant molecules, be they of amphiphilic topology (e.g. tri-n-butylphosphate, TBP; carbamoylphosphinoxide, CMPO; calixarenes) or more symmetrical like crown ethers [17] or cryptands [18]. Monovalent K+ C 222 and divalent Ba2+ C 222 cation cryptates were recently simulated and also found to be surface active [19].…”

The effect of solvent heterogeneity on the solvation and complexation of alkali cations by 18-crown-6: a simulation study in the 90 : 10 chloroform/methanol mixture

“…We note the analogy between the solvation properties of the chloroform/methanol mixture, often used as membrane mimics, with those of water/oil interfaces where extractant molecules (like 18C6, the [222] cryptand, calixarenes, alkylated-amides or -phosphates) and their complexes have been shown to adsorb: 8,32,55,56 although these species prefer the oil phase over the aqueous one (this is the basis of solvent extraction), they are at the interface more attracted by the most polar phase (water) than with the oil phase, and the selectivity at the interface is thus more ''waterlike'' than ''oil-like''. 40 On the other hand, the thermodynamics of M + ions complexation in the 90 : 10 chloroform/methanol mixture behaves differently from that in the 90 : 10 methanol/water one.…”

Ligand Exchange Processes on Solvated Beryllium Cations. II [Be(solvent)(12‐Crown‐4)]2+

“…Today crown ether and other two dimensional macrocyclic ligand systems are applied in phase-transfer catalysis [2,3,4], studies on Zintl phases [5], materials science [6,7,8,9,10], organic synthesis [11], separation of nuclear waste [12], model studies for ion transport across membranes [13], analytical applications [14] and sensors [15], and as models for enzymes [16]. Therefore, crowns and macrocycles, together with the metalla-topomers [17], have been intensively investigated in detail both experimentally [18] and theoretically [19,20,21]. Since crowns of different size and donor numbers are known and easily available, they are common building blocks in all kinds of chemistry [22,23].…”