Quantum Crystallography and Complementary Bonding Analysis of Agostic Interactions in Titanium Amides |
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Authors: | Lorraine A. Malaspina Nils Frerichs Christian Adler Marc Schmidtmann Rüdiger Beckhaus Simon Grabowsky |
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Affiliation: | 1. Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland;2. Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Straße 9–11, DE-26129 Oldenburg, Germany |
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Abstract: | Agostic interactions involving titanium are textbook examples for C−H bond activation. Therefore, it is surprising that there is no study in the literature in which the hydrogen atom in the C−H⋅⋅⋅Ti interaction has been determined reliably, although nearly all the criteria for assessing the strength and character of the agostic interaction depend on the hydrogen atom and its position. Here, we demonstrate with quantum crystallographic techniques how hydrogen atoms in a series of three titanium amides can indeed be localized accurately and precisely based on routine single-crystal X-ray diffraction data. Once the hydrogen positions have been established, theoretical and experimentally fitted bonding analyses reveal that the C−H⋅⋅⋅Ti interaction becomes stronger with increasing inter-ligand London dispersion stabilization of bulky alkyl groups. |
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Keywords: | agostic interactions C−H activation complementary bonding analysis quantum crystallography titanium titanium amides |
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