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Aromaticity and Chemical Bonding of Chalcogen-Bonded Capsules Featuring Enhanced Magnetic Anisotropy |
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| Authors: | Prof Demeter Tzeli Dr Ioannis D Petsalakis Dr Giannoula Theodorakopoulos Dr Faiz-Ur Rahman Prof Pablo Ballester Prof Julius Rebek Jr Prof Yang Yu |
| Institution: | 1. Laboratory of Physical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, Athens, 157 84 Greece;2. Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens, 116 35 Greece;3. Center for Supramolecular Chemistry &, Catalysis and Department of Chemistry, College of Science, Shanghai University, Shanghai, 200444 China;4. Institute of Chemical Research of Catalonia (ICIQ), 43007 Tarragona, Spain
Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain;5. Center for Supramolecular Chemistry &, Catalysis and Department of Chemistry, College of Science, Shanghai University, Shanghai, 200444 China Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute, La Jolla, California, 92037 United States |
| Abstract: | We present a theoretical study of chalcogen bonded container capsules ( AX+AX ) where X=O, S, Se, and Te, and their encapsulation complexes with n-C9H20 (n-C9H20@ AX+AX ). Both Se and Te encapsulation complexes have significant experimental and computed binding energies, analogous to the hydrogen bonded counterparts, while the S and O capsules and their encapsulation complexes show only weak binding energies, which are attributed to different types of bonding: chalcogen S⋅⋅⋅N bonds for S-capsules and π–π stacking and weak hydrogen bonds for the O case. All AX+AX and C9H20@ AX+AX present unusually high magnetic anisotropies in their interiors. The 1H NMR spectra of the encapsulation complexes display the proton signals of the encapsulated n-nonane highly upfield shifted, in agreement with the available experimental data for the Se capsule. We found that different factors contribute to the observed magnetic anisotropy of the capsule's interior: for the Te capsule the most important factor is Te's large polarizability; for the O analogue the inductive effects produced by the electronegative nature of the O and N heteroatoms; and for the S and Se capsules, the polarizability of the heteroatoms combines with electric field effects. |
| Keywords: | capsules cavitands chalcogen bonding density functional calculations magnetic anisotropy molecular recognition |