Research Projects

Research Axis 1 - Isomorphous crystals

Our research in the field of crystal engineering with hydrogen bonds (HB) and halogen bonds (XB) focuses mainly on the creation of new materials (Isomorphous crystals, polar crystals, etc.).
Our main research projects at the Cégep de Sherbrooke aim to study the similarities and differences between HB and XB in order to better use them for the design of new materials. By comparing crystals with relatively similar crystalline parameters and molecular stacking (so-called isomorphous crystals), HB and XB interactions can be compared more efficiently.
The ultimate goal is to have a better understanding and control of these interactions to allow us to generate crystals with unique and flexible properties.

We are the first research group to report a series of four (4) isomorphous crystals of diacetylenes similarly involved in an HB (with H) or in a XB (with X = Cl, Br, I).

The next part of our work is now to use this methodology to compare the properties of the isomorphous crystals with each other.

Research Axis 2 - Polar crystals

A second focus of our research is to use our knowledge of molecular interactions to design polar organic crystals. This is relatively difficult to achieve because the molecules tend to organize themselves by opposing their dipoles due to Keesom forces.
The interest for polar crystals lies in the many properties that are exclusive, or at least generally greatly enhanced, with polar crystals (piezoelectricity, pyroelectricity, ferroelectricity, second harmonic generation, electro-optical effect). (ref.1, ref.2, ref.3)
Our first polar crystals published in 2018 were made from vanillylamine.

These crystals are considered as isosteres of eugenol, a natural compound with important biological and medicinal properties.

Axe 3- Crystal structure of polydiacetylenes

Our last axis of research aims to synthesize and characterize polydiacetylenes (PDAs), a family of semiconductor polymers with unique properties. Indeed, materials composed of this type of molecules have the property of changing color under the effect of an external stimulus (heat, pH, interactions with another molecule, etc.). These polymers are thus the subject of intense research for various applications, for example for the development of optoelectronic components or for the development of carbon monoxide or ammonia sensors to detect food spoilage. We therefore chose to study polydiacetylene crystals (PDAs) in order to better establish a relationship between their structures and their properties. More specifically, we explore two main and original aspects :
1- Biobased polydiacetylenes
The design of biobased polydiacetylenes (PDAs) to eliminate our dependence on fossil resources (such as petroleum). We are thus the first research group to have designed a PDA based on a derivative of the "furan" type (which is derived from lignocellulosic biomass).

2-PolyHalogenoDiAcetylenes (PXDA)
We are also the first group to have isolated a polychlorodiacetylene (PClDA), giving rise to a new family of PDAs. This PClDA has a unique network of H bonds very close to the conjugate skeleton, which causes a helical conformation on this type of PDA.