Dr. GB Hammond Receives NSF Grant
Dr. GB Hammond received an NSF grant for his project titled “Roles of Contact Ion-Pairs as Promoters or Catalysts in Organic Reactions.” The award starts August 1, 2019 and ends July 31, 2022.
Reactions that involve ionic species are among the most useful transformations for the preparation of chemical compounds. In an ionic reaction, ions can be dissociated or they can form tight contact ion pairs. Despite the wealth of empirical information about counterion effects in individual reactions, there is no general quantitative understanding on the effect of ion pairing in a chemical reaction. For the majority of ionic reactions, the selection of counterions is still empirical and relies heavily on a trial and error approach. In this project, Dr. Gerald B. (GB) Hammond is developing a thorough understanding of exactly how ion pairing controls the reactivity of ionic reactions in the preparation of novel materials and new medicines under environmentally responsible and sustainable conditions. Outreach activities are central to Dr. Hammond’s belief that research participation should be widely inclusive, from postdoctoral fellows to undergraduate students, from women to underrepresented minorities. His outreach activities also aim to enhance the recruitment opportunities of Hispanic American students through lecture symposia featuring high-profile Hispanic-American chemists, and through scientific collaborations with research-active Latin American faculty.
Ionic transformations cover a wide range of reaction types, from simple nucleophilic substitutions to complex cationic transition metal catalysis, but the understanding of counterion effects is mainly circumscribed to individual reactions. In most theoretical studies, counterions are simply ignored. With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Gerald B (GB) Hammond, of the University of Louisville in Kentucky, is investigating how contact ion pairs affect their catalytic activity and their promoter role in ionic reactions. Toward this goal, his investigations will generate affinity scales of counterions for various metal and non-metal groups and will implement a new contact ion pair-assisted nucleophilic substitution process (SNip). This conceptually new nucleophilic substitution pathway enables reactivity in those instances where conventional SN2 or SN1 reactions fail. Computational studies of the SNip process will be conducted. Also, under investigation is the design of ion pair promoters—including chiral ion pair promoters with a BINOL backbone—and better electrophiles to facilitate the SNip process. Dr. Hammond is keenly engaged in STEM outreach programs focused on women and underrepresented student recruitment into the STEM fields through summer research internships, in support of the broader impacts of the project.