Projects per year
Abstract
Cryptophane molecules are cage-like structures consisting in two hemispheres, each made of three benzene rings. These hemispheres are bound together with three –O(CH2)nO–linkers of various lengths giving rise to a plethora of cryptophane derivatives. Moreover, they are able to encapsulate neutral guests: CH2Cl2, CHCl3, …; and charged species: Cs+, Tl+, …. Finally, they exhibit chiroptical properties thanks to the anti arrangement of the linkers between the hemispheres. This work focuses on the Raman optical activity (ROA) signatures of Cryptophane-111 (n=1 for each linker). More specifically, we aim at simulating accurately its ROA spectra with and without a xenon atom inside its cavity. Experimental data (Buffeteau et al., 2017) have already demonstrated the effect of the encapsulation in the low-wavenumbers region. To generate the initial structures, we rely on the novel Conformer–Rotamer Ensemble Sampling Tool (CREST) program, developed by S. Grimme and co-workers. This is required due to the flexibility provided by the linkers. The CREST algorithm seems promising and has already been used to sample the potential energy surface (PES) of target systems before the simulation of their vibrational spectroscopies (Eikås et al., 2022). We observe large similarities between the two sets of conformers (one with and one without Xe encapsulated), demonstrating the robustness of the CREST algorithm. For corresponding structures, the presence of xenon pushed the two hemispheres slightly further apart. After optimization at the DFT level, only one unique conformer has a Boltzmann population ratio greater than 1%, pointing out the relative rigidity of the cage. Based on this unique conformer, our simulations are in good agreement with the experimental data. Regarding xenon encapsulation, the (experimental and theoretical) ROA signatures at low wavenumbers are impacted: slight shifts in wavenumbers are observed as well as a decrease in relative ROA intensity for bands around 150 cm−1. The wavenumber shifts were very well reproduced by our simulations, but the experimental decrease in the ROA intensity was unfortunately not reproduced.
Original language | English |
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Article number | 123484 |
Journal | Spectrochimica Acta. Part A: Molecular and Biomolecular Spectroscopy |
Volume | 306 |
DOIs | |
Publication status | Published - 5 Feb 2024 |
Keywords
- Cryptophanes
- Density Functional Theory (DFT)
- Raman optical activity (ROA) Spectroscopy
- ROA Spectroscopy Simulation
- Theoretical Chemistry
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ROA_env: Investigation of the environment effects on the Raman optical activity signatures of flexible solute molecules
D'Haese, L. (PI) & Liegeois, V. (Supervisor)
1/10/23 → 31/12/24
Project: Research
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ROA_env: Investigation of the environment effects on the Raman optical activity signatures of flexible solute molecules
D'Haese, L. (PI) & Liegeois, V. (Supervisor)
28/10/22 → 28/10/26
Project: PHD
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CÉCI – Consortium of high performance computing centers
CHAMPAGNE, B. (PI), Lazzaroni, R. (PI), Geuzaine , C. (CoI), Chatelain, P. (CoI) & Knaepen, B. (CoI)
1/01/18 → 31/12/22
Project: Research
Equipment
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High Performance Computing Technology Platform
Champagne, B. (Manager)
Technological Platform High Performance ComputingFacility/equipment: Technological Platform
Activities
- 1 Oral presentation
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Raman optical activity signatures of cryptophanes derivatives
D'Haese, L. (Speaker)
29 Jan 2024Activity: Talk or presentation types › Oral presentation