Plenary Lecture

Dr. Leonard MacGillivray, Universite de Sherbrooke

Title: Molecular Crystals as Chemical Laboratories: Green Chemistry to Sustainable Materials

Abstract: The ability to reliably form covalent bonds in organic solids promises to provide access to product molecules that may be completely unavailable in solution. Critical covalent bonding forming processes occur in solids without use of solvent and with the materials being accessible using mechanochemistry. Crystal packing, however, is a nemesis of the crystal engineer since covalent bond formations generally require reactive sites to be assembled and oriented in close proximity to react, which can be adversely affected by unpredictable intermolecular forces. In this presentation, a method to direct the formation of covalent bonds in crystals using principles of supramolecular chemistry is described. A main reaction of focus is the [2+2] photodimerization. The method relies on the use of small molecules, coordination complexes, and metal-organic frameworks as templates to assemble olefins via supramolecular synthons into geometries for inter- and intramolecular cycloadditions. The method gives rise to a toolkit that enables the synthesis of complex molecules such as [2.2]cyclophanes, cubanes, and ladderanes. Applications of the products as ligands in coordination-driven self-assembly are described. Relevance of the work to energy capture and release, as well as pharmaceutics, will also be discussed.Thermodynamic and Kinetic Control of Molecular Materials

Time: 11:35 am

Short Talks

Marieh Al-Handawi, NYU Abu Dhabi
Postdoctoral Associate - Naumov Group

Title: Harvesting of aerial humidity with natural hygroscopic salt excretions

Abstract: Plants and animals that thrive in arid regions utilize the diurnal changes in environmental temperature and humidity to optimize their water budget by combining water-harvesting mechanisms and morphophysiological traits. The athel tamarisk (Tamarix aphylla) is a halophytic desert shrub that survives in arid, hypersaline conditions by excreting concentrated solutions of ions as droplets on its surface that crystallize into salt crystals that fall off the branches. Here, we describe the crystallization on the surface of the plant and explore the effects of external conditions such as diurnal changes in humidity and temperature. The salt mixtures excreted by the plant contain at least ten common minerals, these hygroscopic salts play a major role in water harvesting from humid conditions for the tamarix plant. Furthermore, the use of environmentally benign salts as moisture adsorbents could provide a bioinspired approach that complements the currently available water collection or cloud-seeding technologies.

Time: 12:10 pm EST

Bryan Erriah, New York University
Ph.D. Candidate - Ward/Kahr Groups

Title: Overcoming insecticide resistance in Anopheles mosquitoes by using faster-acting solid forms of deltamethrin

Abstract: Controlling the spread of malaria by mosquitoes using insecticides has become increasingly difficult due to the widespread resistance amongst mosquito populations. Developing new insecticides and formulations, however, is a time-consuming and expensive process. By heating a commercial formulation containing crystalline deltamethrin we generated a more bioavailable form. This new solid form of deltamethrin was found to be 12 times faster acting against susceptible North American Anopheles quadrimaculatus mosquitoes. The new solid form was also effective against highly resistant West Africa malaria-spreading mosquitoes expressing target site resistance, metabolic resistance, epicuticular thickening resistance, and chemosensory binding protein resistance for up to 19 months. The new solid form killed 100% of each strain by 24 h post-exposure, whereas the highest mortality observed from the commercial form was approximately 14%. This demonstrates that modifications in the solid state can extend the useful lifetime of insecticides, enabling them to remain effective despite developing insecticide resistance.

Time: 12:40 pm