Boron cluster leveraged polymeric building blocks

Abstract

Boron cluster compounds (BCCs) are inorganic molecules characterized by their unique physical and chemical properties. Polymeric materials incorporating BCCs exhibit significant chemical and thermal stability, making them valuable for applications in biomedical fields, energy storage, ultrahigh stability materials, and π-conjugated luminochromic polymers. This review article aims to explore the primary methods for integrating these distinctive clusters into traditional carbon-based polymers. Both boron and carbon atoms possess catenation abilities, enabling the formation of extensive macromolecular structures. While carbon forms long linear chains, boron typically leads to three-dimensional polyhedral clusters. We first examine hybrid nanostructures, focusing on weak non-covalent interactions such as dihydrogen bonding, hydrophobic, and chaotropic effects between boron clusters and polymer chains. We then discuss classical chemical bonding approaches. Despite their inorganic nature, boron clusters can undergo exoskeletal substitution akin to organic counterparts, allowing their attachment as side groups to polymer repeating units. Additionally, polyhedral boron clusters can be incorporated into polymer backbones primarily through polycondensation reactions, resulting in hybrid macromolecules with exceptional physical and chemical attributes. Finally, we summarize the applications of BCC-containing polymeric materials, including their use in boron neutron capture therapy (BNCT), solid polymer electrolytes (SPEs) for metal ion batteries, and as electron acceptor groups in stimuli-responsive luminescent materials. In summary, BCC-containing polymeric materials are increasingly considered viable alternatives to traditional hydrocarbon-based polymers for biomedical applications, ion-conducting materials, luminescent materials, and temperature-resistant materials.