Molecular dynamics simulations have been investigated to study the interactions between single-wall carbon nanotubes and an anticancer agent Pt complex (Cisplatin). The optimized diameter of the vector system has been determined to encapsulate in the best conditions the drug molecules. The simulation results show also that several drug molecules can be adsorbed inside the nanotubes, leading to an increased confinement time. Moreover, our simulations show that the release of the drug near a cell membrane model is favored, opening the way to a natural drug nanocapsule.

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In recent years and with the achievement of nanotechnologies, the development of experiments based on carbon nanotubes has allowed to increase the ionic permeability and/or selectivity in nanodevices. However, this new technology opens the way to many questionable observations, to which theoretical work can answer using several approximations. One of them concerns the appearance of a negative charge on the carbon surface, when the latter is apparently neutral. Using first-principles density functional theory combined with molecular dynamics, we develop here several simulations on different systems in order to understand the reactivity of the carbon surface in low or ultra-high confinement. According to our calculations, there is high affinity of the carbon atom to the hydrogen ion in every situation, and to a lesser extent for the hydroxyl ion. The latter can only occur when the first hydrogen attack has been achieved. As a consequence, the functionalization of the carbon surface in the presence of an aqueous medium is activated by its protonation, then allowing the reactivity of the anion.

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The oxidative addition of primary amine on a monocyclic phospholane was studied in confined conditions. This one-step chemical reaction has been investigated using the DFT technique to elucidate the role of confinement in carbon nanotubes on the reaction. Calculations were carried out by a progressive increase of the nanotube diameters from 10 Å to 15 Å in order to highlight the dependence of the reactivity on the nanotube diameter. First, single point investigations were dedicated to the study of reactants, transition states, and products placed in the different nanotubes while keeping their optimized structure as free compounds. Second, all studied compounds were relaxed inside nanotubes and their geometries were fully optimized. Within these approaches, we proved that the activation barrier could be controlled depending on the confinement, generating a well-controlled catalysis process.

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Oxidative addition of aliphatic amine on monocyclic 2-R-1,3,2-dioxaphospholane (R = methyl or phenyl) leading to phosphoranes bearing a P H axial bond was investigated using a combined theoretical and experimental approach. The reaction followed first order kinetics for both reactants. The activation parameters were consistent with a concerted mechanism exhibiting stereo, enantio, and regio specificities.Systematic density functional theory studies including reactivity descriptors, structural parameters, determination of all possible phosphorane isomers, their transition states and their formation mechanisms were carried out to delineate the reaction pathway. Depending on the nature of the atom in the final apical position (H, N of the amine, or C of the methyl), three types of phosphoranes were identified. Energy profiles, using the intrinsic reaction coordinate technique for the formation of each isomer, were established. It was shown that the phosphorus biphilicity acts in three consecutive sequences, namely nitrogen nucleophilic attack leading to a supermolecule structure, nucleophilic behavior of phosphorus in the transition state zone of influence, and electrophilic approach of the nitrogen atom to complete the reaction. Phosphorane with an equatorial P H bond was found to be a kinetic product that transforms rapidly to the thermodynamically stable isomer with axial P H via two consecutive Berry pseudo-rotations. A new tool, referred to reactive internal reaction coordinates, was introduced to represent the reaction path more clearly.