Abstract: The expansion of cluster moieties containing main group and transition metal fragments have gained enormous interest due to their numerous structural diversities. [1] In addition, the expansion of higher vertex polyhedral boron clusters allows one to investigate unique bonding and their exceptionally larger size electronic structures. Fehlner et al. showed two complementary approaches for the preparation of metallaborane clusters from transition metal complexes. For example (i) condensation reaction involving monoborane precursors (LiBH4∙thf, BH3∙thf or BHCl2∙SMe2, etc.; thf = tetrahydrofuran) and cyclopentadienyl metal halides and (ii) insertion or fragmentation involving “pre-assembled” borane fragments.[2] and. the intercluster fusion of smaller to larger clusters, such as tetrahedral, octahedral, and trigonal-prismatic, square antiprismatic, or icosahedral fragments, that share one, two, or more atoms common in between the subclusters. However, in most of the cases, these synthetic approaches end up resulting in cluster fusion [3], instead of core expansion of a single cage cluster. In this seminar, the development of more accessible routes single-cage cluster growth from preformed metallaborane clusters as well as preliminary result of my research work in this field will be discussed.

References:
[1]. (a), A N. Simonov, J. F. Boas, M. A. Skidmore, C. M. Forsyth, E. Mashkina, M. Bown, A. M. Bond, Inorg. Chem. 2015, 54, 4292-4302. (b) J. Bould, M. G. S. Londesborough, V. Passarelli, W. Clegg, P. G. Waddell, J. Cvacka and R. Macias, Dalton Trans., 2021, 50, 16751-16764.
[2]. (a) Kar, S.; Pradhan, A. N.; Ghosh, S. Polyhedral Metallaboranes and Metallacarboranes. In Comprehensive Organometallic Chemistry IV; Parkin, G., Meyer, K., O’hare, D., Eds.; Elsevier, 2022; Vol. 9, pp 263– 369.(b) T. P. Fehlner, J.-F. Halet, J.-Y. Saillard. Molecular Clusters. A Bridge to Solid-State Chemistry,Cambridge (2007).
[3]. (a) N. S. Hosmane, R. N. Grimes, Inorg. Chem. 1980, 19, 3482-3487; (b) C. Nandi, A. Roy, K. Kar, M. Cordier, S Ghosh, Inorg. Chem. 2022, 61, 42, 16750–16759. (C) unpublished results.