CAREER: Dispelling Chemical Misconceptions to Discover New Pnictogen-Chalcogen Bonding/Reactivity and Enhance Transfer Student Success

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

With funding from the Chemical Synthesis Program in the Division of Chemistry, Dr. Timothy Johnstone of the Department of Chemistry at the University of California–Santa Cruz, will explore the synthesis and reactivity of chemical bonds involving heavy elements of the pnictogen family with elements of the halogen family and the role of chemistry misconceptions in the educational outcomes of transfer students. Chemical bonding is the bedrock of the understanding of chemistry. The discovery of new types of bonds opens access to new, often unexpected types of chemical compounds and reactivity. This project will prepare heretofore unknown compounds of the heavy atoms antimony and bismuth with double bonds to oxygen, sulfur, selenium and tellurium. These heretofore unkown bond types may allow reactivity that has historically been accessible only using very expensive metals such as platinum and gold. Such advancements allow the diversify the sorts of chemical platforms that may be accessed and exploited across the chemical sciences - very fundamental. The educational plan of this proposal focuses on understanding whether chemical misconceptions, which play a role in the learning of all chemistry students, differ between students that transfer into a four-year degree program from the community college system (transfer students) and students that enter directly into a four-year degree program (non-transfer students). The differences in chemical misconceptions held by transfer students and non-transfer students will be elucidated with surveys conducted at UC Santa Cruz. The efficacy of active-learning interventions developed to specifically target these misconceptions will then be tested. This project will target the synthesis of compounds featuring unsaturated bonds between heavy pnictogens (antimony and bismuth) and chalcogens (oxygen, sulfur, selenium, and tellurium): pnictine chalcogenides and pnictinidene chalcogenides. Pnictine chalcogenides feature the pnictogen in the 5+ oxidation state and pnictinidene chalcogenides feature the pnictogen in the 3+ oxidation state; each bears a distinct type of unsaturated bond between the pnictogen and the chalcogen. In cases where there is a significant electronegativity difference between these two elements, the unsaturated bond is highly reactive. To prevent premature quenching of this reactivity, sterically bulky groups will be installed on the pnictogen center to kinetically stabilize the target compounds. Once isolated, their reactivity will be systematically explored, with an emphasis on stoichiometric and catalytic small-molecule activation reactions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.