Metallaboranes and metallaheteroboranes: An overview of single-cage and condensed polyhedral clusters

Over time, cluster growth reactions for higher nuclearity clusters transformed into the main goal in polyhedral metallaborane and metallaheteroborane chemistry. Metallaboranes and their associated chemistry were first created as a form of metal-ligand coordination chemistry, similar to organometallic chemistry. However, the links between seemingly dissimilar compounds such as polyhedral boranes and transition metal clusters were identified, thanks to the understanding provided by various electron counting rules and the isolobal analogy principle. To get perspective on the special structure and bonding found in these types of compounds, Wade-Mingos rules and Jemmis mno rule were helpful. This clearly defined the scope of this field, and significant progresses toward the enhancement of synthetic pathways were observed. This chapter describes an overview of several complementary approaches towards the expansion of cluster framework especially to build higher vertices single-cage and condensed clusters highlighting their structural diversities, unique bonding and electronic structures.