Aggregation-Dependent Photoreactive Hemicyanine Assembly as a Photobactericide

Abstract

Organic materials that show substantial reactivity under visible light have received considerable attention due to their wide applications in chemical and biological systems. Hemicyanine pigments possess a strong intramolecular donor–acceptor structure and thereby display intense absorption in the visible spectral region. However, most excitons are consumed via the twisted intramolecular charge-transfer (TICT) process, making hemicyanines generally inert to light. Herein, we describe the development of an amphiphilic hemicyanine dye whose aggregation could be easily regulated using salt or counterions. More importantly, its intrinsic photoreactivity was successfully induced by steric restriction and cofacial arrangement within the H-aggregate, thus creating an effective photobactericide. This strategy could be extended to the development of photocatalysts for photosynthesis and a photosensitizer for photodynamic therapy.

Mechanochemistry toward Organic “Salt” via Integer‐Charge‐Transfer Cocrystal Strategy for Rapid, Efficient, and Scalable Near‐Infrared Photothermal Conversion

“…[10] This synergistic effect also exists in D2m-F4TCNQ cocrystals, but is relatively weaker in D2b-F4TCNQ cocrystals with olefinic C=C stretching vibration (1580 cm À 1 ) and weaker intramolecular CT in D2b (Figure S8b). It can be explained by bulk effect of longer alkyl chains in amino moiety hindering the intramolecular CT of D2b in D2b-F4TCNQ cocrystals, [27] which is less affected by intermolecular CT between D2b and F4TCNQ. It's expected that weaker synergistic effect in D2b-F4TCNQ may have negative influence on its PTC performance.…”

An activatable near-infrared hemicyanine-based probe for selective detection and imaging of Hg2+ in living cells and animals

“…[35][36][37] The sensing mechanism is mediated by intramolecular charge transfer (ICT) between the donor and acceptor due to the D-π-A motif characteristics of hemicyanine. 38,39 The hemicyanine scaffold is covalently attached to a specific response moiety, which reduces the electron-donating ability of the donor, resulting in ICT blocking and fluorescence quenching. 30,40,41 Upon exposure to the targeted biomarkers, the response moiety is selectively removed to restore the fluorescence.…”

Aggregation/Viscosity-Induced Emission and Third-Order Nonlinear Optical Signal Inversion in a TICT System

“…Twisted intramolecular charge transfer (TICT) is a photophysical process that happens in some organic luminogens upon light excitation. Molecules with rotatable D−π–A structures, that is, connecting electron-donating (D) and electron-accepting (A) groups via π-conjugated linkers and rotatable single bonds, usually exhibit TICT property. − The TICT process endows the luminogens with different electronically excited state energy levels, resulting in some excellent photophysical properties such as long emission wavelengths, controllable luminescence lifetimes, and nonlinear optical (NLO) characters. − …”

“…The crude product was purified by column chromatography (petroleum ether/ethyl acetate = 10:1) to give the vermilion target product. 1 H NMR (400 MHz, CDCl 3 ) δ (ppm): 9.00 (dd, J = 4.1, 1.6 Hz, 1H), 8.37 (dd, J = 8.3, 1.6 Hz, 1H), 7.69 (d, J = 8.8 Hz, 2H), 7.55 (m, 3H), 6.65 (dd, J = 15.1, 8.9 Hz, 4H), 2.99 (s, 12H). 13 2.3.…”