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

在化学部化学合成计划的资助下，加州大学圣克鲁斯分校化学系的蒂莫西·约翰斯通博士将探索涉及氮族元素家族重元素与卤素家族元素的化学键的合成和反应性，以及化学误解在转学生教育成果中的作用。化学键是理解化学的基础。新类型化学键的发现为新的、通常意想不到的化合物和反应性类型开辟了道路。该项目将制备迄今未知的重原子锑和铋与氧、硫、硒和碲形成双键的化合物。这些迄今为止未知的键类型可以允许历史上仅使用非常昂贵的金属如铂和金才可获得的反应性。这些进步使得可以在化学科学中访问和利用的化学平台种类多样化-这是非常重要的。本提案的教育计划侧重于了解在所有化学学生的学习中发挥作用的化学误解是否在从社区学院系统转入四年制学位课程的学生（转学生）和直接进入四年制学位课程的学生（非转学生）之间存在差异。在化学错误的概念所持有的转学生和非转学生的差异将阐明在加州大学圣克鲁斯进行的调查。本项目的目标是合成具有重氮族元素（锑和铋）和硫族元素（氧、硫、硒和碲）之间不饱和键的化合物：氮族元素硫族化物和氮族元素硫族化物。磷属元素硫族化物以5+氧化态的磷属元素为特征，磷属元素硫族化物以3+氧化态的磷属元素为特征;每种硫族化物在磷属元素和硫族元素之间具有不同类型的不饱和键。在这两种元素之间存在显著电负性差异的情况下，不饱和键是高度反应性的。为了防止这种反应性的过早淬灭，空间上庞大的基团将被安装在氮族元素中心上以动力学稳定目标化合物。一旦分离出来，它们的反应性将被系统地探索，重点是化学计量和催化小分子活化反应。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

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.