THEORETICAL STUDIES ON TRI-n-BUTYL PHOSPHATE: MD SIMULATIONSIN VACUO, IN WATER, IN CHLOROFORM, AND AT A WATER / CHLOROFORM INTERFACE.

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

“…55 On the computational side, we found that macrocyclic molecules like cryptands, calixarenes, or acyclic ones like CMPO or TBP, adsorb at the interface. [17][18][19][20][21]56 Our calculations on 18C6 are consistent with these data. However, the picture of the (18C6) 10 aggregate differs from that of (TBP) 10 21 or of (TPTZ) 16 (Fig.…”

“…47,53 Neutral extractant molecules like TBP form a monolayer at the water/ dodecane interface 54 , a feature which was nicely reproduced by MD simulations. 21 The enthalpy of adsorption of TBP is comparable to, or somewhat larger than the enthalpy of migration to the organic phase (-10.9 and -10.3 kcal/mol, respectively). 54 Similarly, the amphiphilic L-tryptophan molecule adsorbs at the water/ octanol interface and its free energy of adsorption (-5.5 kcal/mol) is larger than its free energy of transfer (-1.4 kcal/mol).…”

“…Generally, the orientation of ionophores at the interface favors the ion capture from the aqueous phase (see TBP 21 , or the 5-Br-PADAP molecule 57 ). Cyclic ionophores like valinomycin with non equivalent faces adopts at the interface an orientation suitable for ion capture.…”

“…In previous publications we considered monomers of calixarenes, cryptand, in various conformations 17 , and of their cation complexes [17][18][19] at the water chloroform interface. Other extractant molecules like CMPO 20 , TBP 21 , phosphoryl containing podants molecules 19 , valinomycin 22 were also simulated. One important result was the high affinity of these species for the interface.…”

Molecular Dynamics Study of the Behaviour of TBP-Zinc-Chloride Complex at the Chloroform/Water Interfacial System

“…Due to their amphiphile structure, these types of compounds are able to adsorb and modify the interface. This property is used for the interpretation of extraction mechanism (8).…”