Projects per year
Abstract
Density functional theory calculations are used to reveal the relationships between the structures, energies, and NMR signatures of an octastate molecular switch composed of a dithienylethene (DTE) unit covalently linked to an indolino[2,1-b]oxazolidine (BOX) moiety through an ethylenic junction. Both the DTE and BOX moieties can adopt open or closed forms. The ethylenic junction can be Z or E, but the latter has been confirmed to be, by far, more stable than the former for all BOX/DTE combinations. In addition, when the DTE is open, the two thienyl units can fold to form parallel conformers, by opposition to the antiparallel or unfolded conformers. Usually parallel conformers present a higher energy than the antiparallel ones, but in the case of compound 2 having a bulky substituent (R = pPh-SMe) on the terminal thienyl group, the enthalpy of one conformer is very close (1−2 kJ mol−1) to that of the most stable antiparallel one, making photocyclization less efficient. These conformational differences and the presence of parallel DTE forms have been substantiated by analyzing experimental 1H NMR chemical shifts in light of their calculated values. These 1H NMR chemical shift calculations led to the following statements: (i) Going from state I (DTE open, BOX closed) to state II (both DTE and BOX are open) the H8 proton of compound 1 (R = Me) is deshielded by ∼0.15 ppm. (ii) The deshielding of H8 proton of compound 2 is larger and attains 0.41 ppm whereas H7 is more shielded by 0.11 ppm. (iii) Then, going from compound 1 to compound 2 leads to deshielding of both H7 and H8 protons. As a consequence, the difference of photochromism gating efficiency among compounds 1, 2, and 3 (R = pPh-OMe) can be attributed to the stabilization of parallel conformer due to an establishment of an intramolecular interaction with BOX opening.
Original language | English |
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Pages (from-to) | 1800-1808 |
Number of pages | 9 |
Journal | Journal of Physical Chemistry C: Nanomaterials and interfaces |
Volume | 122 |
Issue number | 3 |
DOIs | |
Publication status | Published - 25 Jan 2018 |
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CÉCI – Consortium of high performance computing centers
CHAMPAGNE, B., Lazzaroni, R., Geuzaine , C., Chatelain, P. & Knaepen, B.
1/01/18 → 31/12/22
Project: Research
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Moriarty: Multi or individual addressability of multi-responsive topological system
CHAMPAGNE, B., Sanguinet, L., Beaujean, P. & Quertinmont, J.
1/01/17 → 31/12/18
Project: Research
Equipment
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High Performance Computing Technology Platform
Benoît Champagne (Manager)
Technological Platform High Performance ComputingFacility/equipment: Technological Platform
Student theses
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Multi-Scale Quantum Chemistry Investigation of Molecular Switches: From Solution to Crystal
Author: Quertinmont, J., 8 Oct 2020Supervisor: CHAMPAGNE, B. (Supervisor), Olivier, Y. (President), Henrard, L. (Jury), WOUTERS, J. (Jury), Leyssens, T. (External person) (Jury) & Maschio, L. (External person) (Jury)
Student thesis: Doc types › Doctor of Sciences
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