Showing papers by "Mireille Blanchard-Desce published in 2005"

Practical and Efficient Synthesis of Tris(4-formylphenyl)amine, a Key Building Block in Materials Chemistry

Abstract: A short, practical and efficient preparation of tris(4-formylphenyl)amine, a key building block in materials chemistry, is described. It involves a two-flask synthesis from triphenylamine, which requires shorter overall time than the direct one-flask threefold Vilsmeier-Haack formylation, while giving higher yields. The reaction levels off at the disubstitution stage, due to the deactivation of the bis-iminium intermediate, but hydrolysis of the latter into a less deactivated dialdehyde allows the third formylation to occur. The simple experimental protocol makes this method more convenient than the previously reported procedures.

Nonlinear optical detection of fast cellular electrical activity

Abstract: The present invention is directed to various methods involving nonlinear microscopy and dyes that are sensitive to fast cellular membrane potential signals and capable of generating nonlinear optical signals. The present invention includes methods of producing high spatiotemporal resolution images of electrical activity in cellular tissue, as well as methods of detecting and investigating disease within a particular cellular tissue of a living organism. The present invention further relates to methods of detecting membrane potential signal changes in a neuron or a part of a neuron, as well as in a population of cells.

Novel boron quadrupolar NLO-phores: optimization of TPA/transparency trade-off via molecular engineering

Abstract: Molecular two-photon absorption (TPA) has attracted a lot of interest over recent years due to the many applications it offers both in biological imaging and in material science, constantly needing new optimized molecules with large TPA cross-sections. Various structures and functional groups have been studied; however, the use of electron-withdrawing boron groups has not been fully examined yet. As such compounds are known to lead to interesting photoluminescence and nonlinear optical (NLO) properties, we have investigated the TPA properties of a novel series of A-π-A quadrupoles, based on dimesitylborons as acceptor end-groups. Our experimental study reveals that intramolecular charge transfer is a crucial point in these TPA fluorophores, and can be modulated via changing the planarity of the molecule. We have obtained such planar molecules using vinylene spacers, which can release the steric hindrance close to the dimesitylboron end-group. The series of NLO-phores described here is promising for optical power limiting, with excellent TPA/transparency trade-off, and the work has highlighted that perfluorophenylene could be a key component for the future of TPA.