Date: Thursday, December 9, 2021
Time: 1:00 pm EST

Plenary Lecture

Speaker: Ahmad Y. Sheikh, Ph.D., ACOS Senior Research Fellow and Head of Solid-State Chemistry at AbbVie

Title of Talk: Conformation flexibility, chameleonic behavior and solid form complexity

Abstract: Directacting anti-viral regimens have transformed therapeutic management of Hepatitis C across all prevalent genotypes. Most of the chemical matter in these regimens comprise of molecules well outside the traditional drug development chemical space and present significant challenges. Herein implications of high conformational flexibility and the presence of a 15-membered macrocyclic ring in Paritaprevir are reported through a combination of advanced computational and experimental methods with focus on molecular chameleonicity and crystal form complexity. The studies help explain how an evolving balance of inter and intra molecular interactions emanating from conformational flexibility drives properties and performance from crystallization to dissolution, permeation, and docking into the protein pocket.

Time: 1:00 pm EST

Short Talks

Speaker: Travis Mitchell, Graduate Student, Benedict Group, University of Buffalo

Title of Talk: Computationally and Experimentally Derived Parameters for Dithienylethene Based Crystalline Solids

Abstract: Dithienylethenes (DTEs) belong to a class of molecular switches called photochromes which undergo a reversible isomerization induced by light in at least one direction. DTEs are well known for their photoactivity in the solid state and their ability to endure multiple reaction cycles without significant loss of photoactivity. These properties make DTEs promising molecular building units for creating crystalline solids that require a molecular switch controlled by light. One significant limitation of DTEs is that they can assume one of four unique conformations; furthermore, only one of these conformations is considered photoactive. This conformational flexibility complicates the design process for DTE based crystalline solids, because there is no guarantee that the photoactive conformer will occupy the lattice resulting in photoinactive crystalline solids. Herein, we use computational methods to help analyze nineteen unique DTE based crystalline solids to determine whether a conventional route towards designing photoactive DTE based crystalline solids exists.

Time: 1:40 pm EST

Speaker: Robert Stolz, Mirica Group, Dartmouth University

Title of Talk: Conductive Covalent Organic Frameworks in Chemiresistive Sensor Arrays for the Detection and Differentiation of Gasotransmitters

Abstract: This work describes a chemiresistive sensor array using four structurally analogous, but chemically distinct, conductive covalent organic frameworks (COFs) (termed M-COF-DC-8, M=Fe, Co, Ni, Cu) capable of detecting and differentiating between the three gasotransmitters: NO, CO, and H2S at sub-part per million concentrations. These COFs were obtained from the condensation of 2,3,9,10,16,17,23,24-octaaminometallophthalocyanine monomers with pyrenetetraone linkers. Chemiresistive studies show the M-COF-DC-8s can detect a range of oxidizing and reducing gases with ppb-level sensitivities. The partially orthogonal response of M-COF-DC-8s towards these analytes allows the array to differentiate between analytes using multivariate analysis. Spectroscopic investigations using diffuse reflectance infrared Fourier transform spectroscopy, x-ray photoelectron spectroscopy, and electron paramagnetic resonance spectroscopy reveals that the identity of the metallophthalocyanine enables synthetic control over surface chemistry, where selective host–guest interactions are transduced into chemiresistive selectivity in low power devices

Time: 2:10 pm EST