Tschechisch-Deutsches Kooperationsprojekt: Strukturstudien an innen und außen funktionalisierten ikosaedrischen und quadratisch-antiprismatischen Bor-Clustern
Physikalische Chemie von Molekülen, Flüssigkeiten und Grenzflächen, Biophysikalische Chemie
Zusammenfassung der Projektergebnisse
In this project the structures of free molecules in the gas phase of icosahedral carbaborane clusters outerly functionalized with iodine (I), diiodocarbaborane, 9,12-I2-closo-1,2-C2B10H10, as well as the thiol and selenol groups, the carbaboranes closo-1,2-(SH)2-1,2-C2B10H10 and closo-1,2-(SeH)2-1,2-C2B10H10 (SH), were determined by means of gas-electron diffraction and by quantum-chemical calculations. Such molecules are of interest in surface science, because they can bind to surfaces via their SH and SeH functions. Structure determination by X-ray diffraction was so far impossible, due to the lack of suitable crystalline material. Attempts to measure gas electron-diffraction data for Ni(C2B10H11)2 remained unsuccessful due to its low volatility. Due to a shortage in substrates to be studied, the remaining part of the project used the time besides the described structure determinations to develop the instrumentation of the gas-electron diffractometer further (construction of a new all-glass nozzle for metal sensitive compounds) and to refine the methods for data analysis of the diffraction data. For the first time, the structures of such cluster compounds were refined in terms of Cartesian coordinates making use of a recently developed approach of regularization of the least-squares refinement on experimental diffraction data by a complete set of geometry restraints from quantum-chemical calculations with a common regularization parameter, which can be optimized to have a maximum of experimental input. In a further step, a method was developed that allows specifying the amount of experimental and theoretical input for each parameter. This provides now an estimate for each individual parameter as to which extent it is of experimental or theoretical nature. The described approaches can be applied advantageously in the future to structural analyses for all other kind of molecules.
Projektbezogene Publikationen (Auswahl)
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“Influence of Antipodally Coupled Iodine and Carbon Atoms on the Cage Structure of 9,12- I2-closo-1,2-C2B10H10: An Electron Diffraction and Computational Study”, Inorg. Chem. 2015, 54, 11868 - 11874
Yu. V. Vishnevskiy, D. S. Tikhonov, C. G. Reuter, N. W. Mitzel, D. Hnyk, J. Holub, D. A. Wann, P. D. Lane, R. J. F. Berger, S. A. Hayes
