Thiaboranes on Both Sides of the Icosahedral Barrier: Retaining and Breaking the Barrier with Carbon Functionalities

0506139 - ÚACH 2020 RIV DE eng J - Článek v odborném periodiku
Holub, Josef - Vrána, J. - Růžička, A. - Růžičková, Z. - Fanfrlík, Jindřich - Hnyk, Drahomír
Thiaboranes on Both Sides of the Icosahedral Barrier: Retaining and Breaking the Barrier with Carbon Functionalities.
ChemPlusChem. Roč. 84, č. 7 (2019), s. 822-827. ISSN 2192-6506. E-ISSN 2192-6506
Grant CEP: GA ČR(CZ) GA17-08045S
Institucionální podpora: RVO:61388980 ; RVO:61388963
Klíčová slova: clusters * heats of formation * icosahedra * multicenter bonding * thiaborane
Obor OECD: Inorganic and nuclear chemistry; Physical chemistry (UOCHB-X)
Impakt faktor: 2.753, rok: 2019
Způsob publikování: Omezený přístup
https://onlinelibrary.wiley.com/doi/full/10.1002/cplu.201900115

The concept of icosahedral barrier has been expanded from the chemistry of carbaboranes to the area of thiaboranes. Both representatives of this barrier, i. e., closo-1,2-C2B10H12 and closo-1-SB11H11, are similar in their electron distribution, which is dominated by positive charge in the midpoint of the C−C vector and on the sulfur atom with experimentally determined dipole moments of 4.50 D and 3.64 D, respectively. This is a driving force for their reactivity as exemplified by their reactions with different carbon functionalities. Icosahedral closo-1-SB11H11 reacts both with an electron sextet containing carbon (in the form of N-heterocyclic carbenes), reported earlier, and with methyl iodide with an electron octet on the carbon. The latter reaction provides hexamethylated thiaborane on the basis of methylation so far unknown in this area of heteroborane chemistry. The computations of the heat of formation (ΔHf298) make it possible to estimate the height of the barrier as well as to propose closo-thiaboranes beyond the barrier. Eleven and twelve vertex thiaboranes with nido electron count are known experimentally for breaking the barrier. These computations also suggest that the larger nido-thiaboranes are promising candidates for the corresponding experimental availability, i. e., the ΔHf298 of a 13-vertex nido-thiaborane cluster has been computed to be more negative than that of the well-known nido-SB10H11− cluster (−6.7 and −5.6 kcal mol−1 per vertex, respectively).
Trvalý link: http://hdl.handle.net/11104/0297556