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. 2023 Jul 26;28(15):5646.
doi: 10.3390/molecules28155646.

Photoswitchable Molecular Units with Tunable Nonlinear Optical Activity: A Theoretical Investigation

Aggelos Avramopoulos  1 , Heribert Reis  2 , Demeter Tzeli  3   4 , Robert Zaleśny  5 , Manthos G Papadopoulos  2
Affiliations

Photoswitchable Molecular Units with Tunable Nonlinear Optical Activity: A Theoretical Investigation

Aggelos Avramopoulos et al. Molecules. .

Abstract

The first-, second-, and third-order molecular nonlinear optical properties, including two-photon absorption of a series of derivatives, involving two dithienylethene (DTE) groups connected by several molecular linkers (bis(ethylene-1,2-dithiolato)Ni- (NiBDT), naphthalene, quasilinear oligothiophene chains), are investigated by employing density functional theory (DFT). These properties can be efficiently controlled by DTE switches, in connection with light of appropriate frequency. NiBDT, as a linker, is associated with a greater contrast, in comparison to naphthalene, between the first and second hyperpolarizabilities of the "open-open" and the "closed-closed" isomers. This is explained by invoking the low-lying excited states of NiBDT. It is shown that the second hyperpolarizability can be used as an index, which follows the structural changes induced by photochromism. Assuming a Förster type transfer mechanism, the intramolecular excited-state energy transfer (EET) mechanism is studied. Two important parameters related to this are computed: the electronic coupling (VDA) between the donor and acceptor fragments as well as the overlap between the absorption and emission spectra of the donor and acceptor groups. NiBDT as a linker is associated with a low electronic coupling, VDA, value. We found that VDA is affected by molecular geometry. Our results predict that the linker strongly influences the communication between the open-closed DTE groups. The sensitivity of the molecular nonlinear optical properties could assist with identification of molecular isomers.

Keywords: (hyper)polarizability; bis(ethylene-1,2-dithiolato); density functional theory; dithienylethene; excited-state energy transfer; molecular switches; photochromism; two-photon absorption.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
The structures of 1cc, 1co, and 1oo computed using the B3LYP/6-31G* method.
Figure 2
Figure 2
The structures of 2oo, 2oc, 2cc, 3oo, and 3oc, computed using the B3LYP/6-31G* method.
Figure 2
Figure 2
The structures of 2oo, 2oc, 2cc, 3oo, and 3oc, computed using the B3LYP/6-31G* method.
Figure 3
Figure 3
The considered dimers (left fragment: donor; right fragment: acceptor.
Figure 4
Figure 4
The absorption (black line) and the emission spectra (red, green, and blue lines) of the 2oc fragments (left fragment: donor, right fragment: acceptor). The CAMB3LYP/6-31G* method was used.
Figure 5
Figure 5
Calculated open–open (2oo), open–closed (2oc), and closed–closed (2cc) structures at CAM-B3LYP/6-31G* H,C,O,F,S ECP28MWB(SDD)Ni.
Figure 6
Figure 6
NIR-vis-UV absorption (solid line) and emission (dotted line) spectra of the 2oo, 2oc, and 2cc structures at CAM-B3LYP/6-31G* H,C,O,F,S ECP28MWB(SDD)Ni level of theory. (Peak half-width at half height: 0.09 eV).
Figure 7
Figure 7
Frontier molecular orbitals (MO) involving in the main absorption and emission excitations of 2oo. (a) absorption excitation of the a conformer (b) absorption excitation of the b conformer.
Figure 8
Figure 8
Frontier molecular orbitals (MO) involving in the main absorption and emission excitations of 2oc.
Figure 9
Figure 9
Frontier molecular orbitals (MO) involving in the main absorption excitations of 2cc.
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References

    1. Fihey A., Russo R., Cupellini L., Jacquemin D., Mennucci B. Is energy transfer limiting multiphotochromism? answers from ab initio quantifications. Phys. Chem. Chem. Phys. 2017;19:2044–2052. doi: 10.1039/C6CP07458H. - DOI - PubMed
    1. Galanti A., Santoro J., Mannancherry R., Duez Q., Diez-Cabanes V., Valasek M., De Winter J., Cornil J., Gerbaux P., Mayor M., et al. A New Class of Rigid Multi(azobenzene) Switches Featuring Electronic Decoupling: Unravelling the Isomerization in Individual Photochromes. J. Am. Chem. Soc. 2019;141:9273–9283. doi: 10.1021/jacs.9b02544. - DOI - PubMed
    1. Hsu C.P. The Electronic Couplings in Electron Transfer and Excitation Energy Transfer. Acc. Chem. Res. 2009;42:509–518. doi: 10.1021/ar800153f. - DOI - PubMed
    1. Nakamura Y., Aratani N., Osuka A. Cyclic porphyrin arrays as artificial photosynthetic antenna: Synthesis and excitation energy transfer. Chem. Soc. Rev. 2007;36:831–845. doi: 10.1039/b618854k. - DOI - PubMed
    1. Zhang L.Y., Friesner R.A., Murphy R.B. Ab initio quantum chemical calculation of electron transfer matrix elements for large molecules. J. Chem. Phys. 1997;107:450–459. doi: 10.1063/1.474406. - DOI

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