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The Quest for Photoswitches Activated by Near‐Infrared Light: A Theoretical Study of the Photochemistry of BF 2 ‐Coordinated Azo Derivatives
Author(s) -
Moreno Miquel,
Gelabert Ricard,
Lluch José M.
Publication year - 2016
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201600543
Subject(s) - photoisomerization , photoswitch , isomerization , azobenzene , density functional theory , chemistry , molecule , photochemistry , rational design , computational chemistry , excited state , combinatorial chemistry , chemical physics , nanotechnology , materials science , organic chemistry , physics , nuclear physics , catalysis
Recently synthesized BF 2 ‐coordinated azo derivatives have been proposed as photoswitches that operate in the optical window ( λ =600–1200 nm) for use in bioimaging applications. Herein, we have theoretically analyzed these compounds and modified some substituents to analyze which properties of the molecule govern its photochemistry. Our results compare rather well with the available experimental data, so our methodology, based on density functional theory (DFT) calculations for the ground electronic state and time‐dependent‐DFT for the first excited electronic state, is validated. Through systematic modification of different substituents of the parent system, we designed compounds that are predicted to operate fully within the optical window. We also analyzed several molecules for which the cis isomer is the more stable isomer, a quite unusual result for azobenzene derivatives that is a much coveted property for some applications of these photoactive molecules in pharmacology. Our results also provide insight into other properties relevant for photoswitches, such as the thermal stability of the less stable isomer and the magnitude of the gap between the wavelengths of the radiation that activates each isomerization process, which must be as large as possible to improve the yield of each photoisomerization. From a more general perspective, our results may provide a step towards the rational design of new photoswitches that fulfill a set of desired characteristics.