Synthesis, gelation and topochemical polymerization of meta-linked oligophenylenebutadiynylene derivatives.

Rational design of meta-linked oligophenylbutadiynylene (OPBD) derivatives was conducted in order to gain insight into their gelation properties and reactivity toward topochemical polymerization to yield polydiacetylenes (PDAs). Different structural parameters influencing the gel formation such as the presence of peripheral 2-hydroxyethoxy side chains and the position of amide functionalities, responsible for intermolecular hydrogen bonds, were studied. Topochemical polymerization of butadiyne units contained within the OPBDs was performed and the resulting PDAs were characterized by electron microscopy and spectroscopy.

Improving the reactivity of phenylacetylene macrocycles toward topochemical polymerization by side chains modification.

The synthesis and self-assembly of two new phenylacetylene macrocycle (PAM) organogelators were performed. Polar 2-hydroxyethoxy side chains were incorporated in the inner part of the macrocycles to modify the assembly mode in the gel state. With this modification, it was possible to increase the reactivity of the macrocycles in the xerogel state to form polydiacetylenes (PDAs), leading to a significant enhancement of the polymerization yields. The organogels and the PDAs were characterized using Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Rigid organic nanotubes obtained from phenylene-butadiynylene macrocycles.

Rigid organic nanotubes were prepared from six-membered phenylene-butadiynylene macrocycles through topochemical polymerization in the xerogel state. All six butadiyne units underwent polymerization, thus creating rigid nanotubes with six polydiacetylene chains lying parallel, one relative to each other.

Soluble conjugated one-dimensional nanowires prepared by topochemical polymerization of a butadiynes-containing star-shaped molecule in the xerogel state.

A star-shaped molecule with three butadiyne moieties attached to a central phenyl core was self-assembled via organogel formation in different solvents and subjected to UV irradiation in its xerogels form to give a soluble conjugated 1D nanowire made of three connected polydiacetylene (PDA) chains. The resulting polymer has a slightly lower optical band gap than its linear counterpart and presents no chromism property, indicative of the rigid nature of the polymer thus obtained.

Topochemical polymerization of phenylacetylene macrocycles: a new strategy for the preparation of organic nanorods.

Soluble organic nanorods were prepared from phenylacetylene macrocycles using the topochemical polymerization of butadiyne moieties placed both inside and outside the macrocycles' skeletons. Macrocycles containing amide groups were self-assembled in a columnar fashion through the formation of an organogel in ethyl acetate. Upon irradiation with UV light, the Raman signals associated with butadiyne units completely vanished, indicating the creation of covalently linked nanorods.

Room-temperature synthesis of soluble, fluorescent carbon nanoparticles from organogel precursors.

Carbon nanoparticles were obtained at room temperature by irradiating an organogel made from a 1,8-diaryloctatetrayne derivative in chloroform. During the topochemical polymerization, the morphology of the gel changes from fibers to soluble, yellow fluorescent nanoparticles in high yield. Analyses suggest that the resulting nanoparticles are made of amorphous graphitic carbon.

H-bonding-driven gel formation of a phenylacetylene macrocycle.

An amide-containing phenylacetylene macrocycle (PAM) has been synthesized and its gelation properties were studied in different solvents. Surprisingly, this macrocycle forms organogels at low concentration in many polar and apolar solvents. XRD and FTIR analysis suggest that this macrocycle forms stable supramolecular assemblies owing to H-bonding. Scanning electron microscopy analyses show the formation of bundles of nanofibrils, demonstrating the long-range organization of this material.

Topochemical polymerization of a diarylbutadiyne derivative in the gel and solid states.

A diarylbutadiyne derivative was synthesized using a few steps and gelified in aromatic solvents. The gel prepared at low concentration is made of micrometers-long nanofibrils as shown by scanning electron microscopy. XRD of the dried gel shows sharp features, revealing a well-organized material. A topochemical reaction was performed on the dried gel, and a polydiacetylene presenting reversible thermochromism properties was obtained.