Résumé
Confinement of molecules and atoms inside nano-containers (NaCons) provides a powerful strategy for creating original hybrid nanostructures and studying structures and chemical properties of individual molecules at the nanoscale. Carbon nanotubes (CNTs) used as NaCons offer different advantages: (1) CNTs are built of sp2carbon atoms held together by strong covalent bonds; (2) They are thermally stable (around 700 °C in air and up to 2800 °C in vacuum); (3) mechanically more robust (with tensile strength much higher than that of steel) than any other molecular or supramolecular NaCons; (4) Their hollow core has very low chemical reactivity. The nanotube diameter is the most important parameter in determining whether or not a molecule can be trapped inside a CNT. Once encapsulated, the behavior of the guest molecule is greatly affected by confinement.We consider here Single-walled carbon nanotubes (SWNTs) having a one-dimensional hollow space of 0.4-2.0 nm that can encapsulate various molecules leading to hybrid nanotubes. Two examples will be reported, the first one concerning the encapsulation of Poly-iodides inside SWNTs; the second one related to the encapsulation of conducting oligomers into SWNTs.We will firstly show that 1D-confinement of polyiodides (In) inside SWNTs lead to specific structural arrangement of iodine species as a function of the SWCNT diameters [1]. Evidence for long range one dimensional ordering of the iodine species is shown by X-ray and electron diffraction experiments independently of the tube diameter. Using X-ray absorption spectroscopy, we show that the confinement influences the local arrangement of the chains. Below a critical diameter c of 1 nm, long linear In are evidenced leading to a weaker charge transfer than for nanotube diameter above c. A shortening of the In is exhibited with the increase of the nanotube diameter leading to a more efficient charge transfer. This point reflects the 1D-confinement of the polyiodides inside the nanotubes.Concerning the study on the confinement of conducting oligomers into SWNTs [2], we evidence by means of Raman spectroscopy and transmission electron microscopy that the supramolecular organizations of the confined oligothiophenes depend on the nanocontainer size. The Raman radial breathing mode frequency is shown to be monitored by both the number of confined molecules into a nanotube section and the competition between oligothiophene/oligothiophene and oligothiophene/tube wall interactions.