Properties of perhalogenated {closo-B10} and {closo-B11} multiply charged anions and a critical comparison with {closo-B12} in the gas and the condensed phase
| Autor: | Sotiris S. Xantheas, Szymon Z. Konieczka, Christoph Kerpen, Gao-Lei Hou, Michael Deckert, Julia Laskin, Grant E. Johnson, Edoardo Aprà, Thomas Schäfer, Maik Finze, Zheng Yang, Xue-Bin Wang, Fabian Keppner, Eric J. Bylaska, Jonas Warneke |
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| Rok vydání: | 2019 |
| Předmět: |
Collision-induced dissociation
Chemistry Substituent General Physics and Astronomy 02 engineering and technology Electronic structure 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences Dissociation (chemistry) 0104 chemical sciences Ion Crystallography chemistry.chemical_compound X-ray photoelectron spectroscopy Chemical stability Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Physical Chemistry Chemical Physics. 21:5903-5915 |
| ISSN: | 1463-9084 1463-9076 |
| Popis: | closo-Borate anions [closo-BnXn]2− are part of the most famous textbook examples of polyhedral compounds. Substantial differences in their reactivity and interactions with other compounds depending on the substituent X and cluster size n have been recognized, which favor specific closo-borates for different applications in cancer treatment, chemical synthesis, and materials science. Surprisingly, a fundamental understanding of the molecular properties underlying these differences is lacking. Here, we report our study comparing the electronic structure and reactivity of closo-borate anions [closo-BnXn]2− (X = Cl, Br, I, n = 10, 11, 12 in all combinations) in the gas phase and in solution. We investigated the free dianions and the ion pairs [nBu4N]+[closo-BnXn]2− by gas phase anion photoelectron spectroscopy accompanied by theoretical investigations. Strong similarities in electronic structures for n = 10 and 11 were observed, while n = 12 clusters were different. A systematic picture of the development in electronic stability along the dimension X is derived. Collision induced dissociation shows that fragmentation of the free dianions is mainly dependent on the substituent X and gives access to a large variety of boron-rich molecular ions. Fragmentation of the ion pair depends strongly on n. The results reflect the high chemical stability of clusters with n = 10 and 12, while those with n = 11 are much more prone to dissociation. We bridge our study to the condensed phase by performing comparative electrochemistry and reactivity studies on closo-borates in solution. The trends found at the molecular level are also reflected in the condensed-phase properties. We discuss how the gas phase values allow evaluation of the influence of the condensed phase on the electronic stability of closo-borates. A synthetic method via an oxidation/chlorination reaction yielding [closo-B10Cl10]2− from highly chlorinated {closo-B11} clusters is introduced, which underlines the intrinsically high reactivity of the {closo-B11} cage. |
| Databáze: | OpenAIRE |
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