Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - multiBB (Boron-boron multiple bonding)

Teaser

The ERC Advanced Grant “Boron-Boron Multiple Bonding” (MULTIBB) is based on the very poorly-understood and little-studied ability of boron to form multiple bonds with itself. While other, more common elements of the first row of the periodic table’s “main block”...

Summary

The ERC Advanced Grant “Boron-Boron Multiple Bonding” (MULTIBB) is based on the very poorly-understood and little-studied ability of boron to form multiple bonds with itself. While other, more common elements of the first row of the periodic table’s “main block” (i.e. carbon, nitrogen, oxygen) all have well-understood multiple bonding abilities, boron’s remained little understood until recently. Our 2012 discoveries of high-yielding, reliable routes to compounds with B-B double and triple bonds – in conjunction with funding as part of the ERC Advanced Grant – has allowed us to embark on a comprehensive exploration of the possibilities of B-B multiple bonding in main-group chemistry, organic chemistry, coordination chemistry, and materials applications.

Work performed

In the first half of the project’s funding period, our team has made significant impacts in a number of areas related to B-B multiple bonding, including: (A) a full exploration of the limits of the synthesis of diborenes and diborynes, allowing us to develop reliable methods for their synthesis and an understanding of what functional/structural groups are likely to make a product stable and isolable; (B) a comprehensive, systematic study of the reactivity of diborenes, leading to the discovery of a range of new reaction patterns and entirely new classes of molecules, e.g. the first transition metal complexes with B-B triple bond ligands; and (C) the physical and theoretical study of B-B multiply-bound species, including extensive collaborations with computational chemists, spectroscopists and magnetochemists. Thus far the project has already yielded over 20 peer-reviewed papers, the majority of which are published in the top general chemistry journals.

Final results

In the second half of the project’s funding period, we expect our progress in the field of B-B multiple bonding to continue in a number of different ways, including: (A) pushing the structural limits of B-B multiply-bound species by installation of groups that will allow new functionality and/or photoactivity, as well as increasing their stability to allow their use in materials; (B) in a contrasting approach, we will also try to decrease the stability of diborenes/diborynes in order to use them as reactive intermediates in novel reactions. By carefully tuning their reactivity, we may be able to induce these species to react with small molecules that are traditionally challenging to activate, such as N2, arenes, and alkanes; (C) extending the family of transition metal complexes of B-B multiply-bound species, in particular due to their exciting tendency to have luminescent properties (both fluorescence and phosphorescence).