The project involved a comprehensive experimental and computational study of the structural limits and properties of compounds containing boron-boron multiple bonds, and the mapping and exploitation of the synthetic abilities of these highly reactive compounds.
The first part of the project involved a wide-scope expansion of the structural diversity of diborenes and diborynes, by altering the two variable components of the compounds, the anionic substituent and the Lewis base unit. While some components were chosen for their stability-enhancing characteristics, others were chosen as they were the opposite, i.e. destabilising and reactivity enhancing. Other units were incorporated as leaving groups, i.e. to direct reactivity of the compound away from the B-B multiple bond and towards other bonds of the molecule. In other cases, functional components were incorporated that allowed us to study the interactions between the B-B multiple bond and the functional unit, such as electronically-conducting, wire-like units, units with empty orbitals, strongly electron-accepting/donating units and units with multiple redox states.
The second part of the project was based on a comprehensive exploration of the reactivity of diborenes and diborynes, taking advantage of their highly electron-rich and reactive nature. Thereby, diborenes and diborynes were subjected to a wide range of reagents in a strategic fashion, ranging from highly reactive species such as strong oxidants to relatively inert molecules of societal and industrial importance, such as carbon dioxide, alkynes, amines, etc. The results of these reactions have radically broadened our understanding of the reactivity of B-B multiple bonds, leading to a long list of bond activation processes. Many of these reactions gave the simple addition product of two groups across the B2 unit or reactions known with their organic counterparts. However, many others gave completely unexpected products, such as C-C bond cleavage products, diborabenzenes, additions across a single boron atom, etc.
The results of the project have been published in 42 peer-reviewed articles, with three further papers currently submitted. A number of manuscripts are in preparation, and many more are planned from the work amassed in this project. 31 of the published articles have appeared in top general science or general chemistry journals with impact factors above nine (e.g. Journal of the American Chemical Society (5), Angewandte Chemie (20), Nature Communications (1), Chemical Science (4), Chemical Reviews (1)) and the average journal impact factor of the articles is 11.7. The published papers have already attracted over 700 citations (Web of Science), with an average number of citations per paper of ca. 18, and two are designated Highly Cited Papers by the Web of Science (top 1% in citations for its field). The publication output includes three major reviews that have been published in premier chemistry journals (one in Chemical Reviews, two in Angewandte Chemie). Eight of the papers emerging from this project have been the subject of highlights by other scientific journals and magazines (Nature Communications, Chemistry World, Angewandte Chemie, Synfacts, Nachrichten aus der Chemie), resulting in ten highlights in total. Results of the project have been communicated in a range of other ways, such as conference participation (ca. 40 oral and poster presentations from the PI, students and postdocs working on the project), lecture tours and award lectures. Overall, the publication output and dissemination from the project is outstanding, leading to an extraordinary amount of attention for the research, the group, the PI, and the host institution. A number of major scientific awards, award lectureships, and fellowships of scientific societies received by the PI have also been based in part on the excellent results of the project.
