Methods to produce B–C, B–P, B–N and B–S bonds in boron clusters

Abstract

Boranes, heteroboranes and metallacarboranes, all named as boron clusters, offer an alternative to typical organic molecules or organic molecular materials. Carbon and boron share the important property of self-catenation thus these elements can produce individually large and sophisticated molecules. Boron clusters and organic molecules display electronic, physical, chemical and geometrical characteristics manifestly different. These differences highlight the complementarity of organic molecules and boron clusters, and therefore the feasibility or necessity to produce hybrid molecules incorporating both types of fragments. To join these two types of fragments, or alternatively these two types of molecular compounds, tools are needed. In this review the current methods of producing boron clusters with carbon, B–C, nitrogen, B–N, phosphorus, B–P and sulphur bonds, B–S, are indicated. As there are many existing borane clusters of different sizes, heteroboranes and metallacarboranes, the revision of methods to generate the B–C, B–P, B–S, and B–N bonds has been restricted to the most widely used boron clusters; [B₁₂H₁₂]²⁻, dianionic and an example of a borane, 1,2-C₂B₁₀H₁₂, neutral and an example of a heteroborane, and [Co(C₂B₉H₁₁)₂]⁻, monoanionic and an example of a metallacarborane.