THE PHYSICS GRADUATE PROGRAM invites everyone to the seminar:
Investigative In-Silico Design of Domed and Cylindrical Cage-Type Cyclophanes – A Computational Insight
Giovanni F. Caramori
Chemistry Department, Federal University of Santa Catarina
The role of functional groups in supramolecular systems determines its ability to recognize other molecules, as well as to rearrange its conformation into a specific shape.1,2,3 Cyclophanes are strained molecular cages that possess unusual chemical behavior, arising from its congested framework. Not only such constrained molecular frameworks are a noteworthy synthetic challenge target, but they are also known for being part of the “Hall of Fame” of molecules with ultra-short non-bonded contacts, and to be selective to determined guests. Cylindrophanes are fluoride selective hosts, which coordinate the anion through anion-π, H-bond, and ion-pair interactions. Both together are great examples that show how crucial such cyclophanes molecular framework is to be chemically investigated. The cyclindrophane unveiled the role of functional groups in the fluoride coordination. Structural modifications proposed to the functional groups in the cylindrophanes were mainly done to determine the importance of the anion-π interactions arising from the π-systems, and the strong short-range H-bond interactions from the bridges binding groups, to the guest stability. The results provided here make use of an avant-garde theoretical approach that elucidated unique structural and energetic aspects of the cage-type of cyclophanes, evaluating, in the light of Kohn-Sham Density Functional Theory (DFT), with dispersion corrections (BJ-D3), both,the influence of the π-systems, and the nature of the heteroatoms located at the bridges. Rationalization of the physical nature of the non-covalent interactions has becoming possible through the use of wave function, and electron density analyses such as Energy Decomposition Analysis (EDA), Natural Bond Orbitals (NBO), Quantum Atoms in Molecules (QTAIM). The role of cylindrophanes functional groups that coordinate the fluoride reveals that the guest stabilization is mainly dependent on the non-covalent interactions with the bridge binding group. The ability of the ligands to better interact with the anion inside the cavity was found to be modulated by the cyclophane π-systems, in that the short-range effects of the binding groups are found to be the strongest in the cylindrophane containing benzene, not the π-acidic arenic systems.
1J. Org. Chem. 2018, 83, 5114-5122
2ChemPhysChem 2020, 21, 1989-2005
3Dalton Trans. 2020, DOI:10.1039/D0DT03518A
Date: December 11, 2020 – (friday) – Time: 10:15 a.m.
link to access the youtube channel: https://youtu.be/479D-CuDHo4