Biomedical subjects
Marc Gingras
Publications and source records attributed to Marc Gingras.
Persulfurated aromatic compounds.
Persulfurated arenes have been known for about 50 years but they were underexploited in chemistry in spite of facile, mild, and high-yielding syntheses. Their properties (redox potentials, UV/Vis absorption, conductivity, nonlinear optical properties, etc.) are mainly due to the aromaticity of the ring with sp2-hybridized carbon atoms and to the electronic contribution from numerous divalent sulfur ligands, which also stabilize negative or positive charges. The characteristic conformational patterns of the sulfur ligands often facilitate preorganization in supramolecular assemblies, with or without thiophilic metal cations, for designing redox sensors, ion-selective membranes, clathrates, organic conductors, nonlinear optical materials, liquid crystals, coordination polymers, and bioinorganic systems. A new class of supramolecules with various molecular shapes such as asterisks, chains, wheels, and windmills were reported.
Star-Shaped nanomolecules based on p-phenylene sulfide asterisks with a persulfurated coronene core.
Persulfurated p-phenylene sulfide (PPS) molecular asterisks (6-9) from "generations" 1 to 4 were efficiently prepared. They represent a new class of electron-accepting PPS star-shaped nanomolecules. Spectroelectrochemistry, cyclic voltammetry and UV-visible studies were performed for the asterisks and for functionalized p-phenylene sulfide oligomers (1-4). These data confirmed for the first time that an electronic delocalization through the whole asterisk molecule exists in the radical anionic or dianionic forms, in spite of divalent sulfur bridges between phenyl groups. They could be seen as globular spheres with a three-dimensional electronic network and delocalization. Electrochemical studies indicated that sulfur substituents strongly stabilize the reduced form of the asterisk relative to coronene itself, and the ease of reduction depends on the PPS chain length.