Synthesis and NLO properties of new trans 2-(thiophen-2-yl)vinyl heteroaromatic iodides

Abstract

The synthesis and characterisation of new trans 2-(thiophen-2-yl)vinyl pyridinium, imidazolium and quinoilinium iodides is reported together with their solvatochromic shifts and EFISH characterization. 2-{(E)-2-[5'-(dibutylamino)-2,2'-bithien-5-yl]vinyl}-1-methyl pyridinium and quinolinium iodides display high μ.β(vec) values up to 1200 × 10(-48) esu. The promising non-linear optical (NLO) properties of this new family of chromophores, which can be further improved by the design of highly efficient systems exploiting the donor and acceptor properties of both heteroaromatic rings and substituents, make them suitable candidates for second harmonic generation imaging with interesting biological applications.

Effect of the π Bridge and Acceptor on Intramolecular Charge Transfer in Push–Pull Cationic Chromophores: An Ultrafast Spectroscopic and TD‐DFT Computational Study

“…The absorption spectra of A – C show a very important blueshift when the solvent polarity is increased (see Figure 3 and Table 1); this strong negative solvatochromism has been already observed in other donor–acceptor charged analogues17–19 and represents a significant peculiarity of this class of chromophores. A large series of solvents belonging to three different classes has been considered: low‐polarity chlorinated media, polar protic, and polar nonprotic solvents.…”

“…For this reason, in the present work we aim to characterize the ICT that occurs in highly conjugated dimethylamino derivatives ( A – C in Figure 1), in which the butadiene replaces the ethylene chain (compounds A and C ) and the stronger acceptor and more planar methylquinolinium substitutes the methylpyridinium chromophore (compounds B and C ). Our interest in this direction has also been raised by recent studies, which have shown that enhanced quadratic hyperpolarizabilities19 and two‐photon absorption20, 21 are obtained in styrylquinolinium with respect to analogous styrylpyridinium derivatives. The experimental investigation is carried out in several solvents of different polarity by employing steady‐state absorption and fluorescence spectroscopies and femtosecond‐resolved transient absorption; the latter allows a direct insight into the excited‐state ICT dynamics.…”

An ultrafast spectroscopic and quantum mechanical investigation of multiple emissions in push–pull pyridinium derivatives bearing different electron donors

“…[3][4][5][6][7][8][9] It has been observed that the extent of the NLO response and the two photon absorption cross-sections are strongly dependent upon the molecular structure of the pushpull molecules and are particularly affected by the strengths of the electron donor/acceptor groups. [14][15][16][17][18] This effect was observed not only in widely studied neutral donor-acceptor systems, but also in cationic chromophores bearing a methyl pyridinium or a methyl quinolinium as an electron deficient moiety, [19][20][21][22][23][24] whose photobehaviour has been less investigated so far and, therefore, not yet deeply understood. [14][15][16][17][18] This effect was observed not only in widely studied neutral donor-acceptor systems, but also in cationic chromophores bearing a methyl pyridinium or a methyl quinolinium as an electron deficient moiety, [19][20][21][22][23][24] whose photobehaviour has been less investigated so far and, therefore, not yet deeply understood.…”

Inclusion of push–pull N-methylpyridinium salts within surfactant hydrogels: is their excited state intramolecular charge transfer mediated by twisting?

“…[1][2][3][4][5][6][7][8] Due to their push-pull character, these compounds can undergo significant photoinduced charge transfer, which makes them suitable for many applications, such as non-linear optical (NLO) materials, 9,10 biological markers 11 and fluorescence indicators for neurons, 12,13 to name but a few. [1][2][3][4][5][6][7][8] Due to their push-pull character, these compounds can undergo significant photoinduced charge transfer, which makes them suitable for many applications, such as non-linear optical (NLO) materials, 9,10 biological markers 11 and fluorescence indicators for neurons, 12,13 to name but a few.…”