Self-assembling of cholesterol-appended benzothiadiazole–triphenylamine two-photon absorption dye

• We examined the self-assembling nature of cholesterol-appended benzothiadiazole–triphenylamine two-photon absorption dye.
• The benzothiadiazole–triphenylamine moieties are arranged with J-like helical stacking mode in the self-assembling.
• The two-photon absorption nature in the parent benzothiadiazole–triphenylamine chromophore is maintained in the self-assembled system.

Cholesterol-appended benzothiadiazole–triphenylamine two-photon absorption dye was prepared and its self-assembling nature was investigated. The dye gave viscous fluid organogels in aliphatic hydrocarbon solutions such as cyclohexane, in which one-dimensional supramolecular aggregates are formed through the van der Waals interactions among the cholesterol moieties and the intermolecular hydrogen-bonding interactions among the carbamate spacer moieties. The supramolecular self-assembling was confirmed by the line-broadening effect in the 1H NMR spectra, and by the bathochromic shifts of the absorption and emission bands. The bathochromic shift of the absorption band suggested that the benzothiadiazole–triphenylamine moieties take a J-like aggregation mode. Under the self-assembled conditions, the dye showed a negative exciton splitting pattern in the CD spectrum, suggesting the one-dimensional stacking with a left-handed twisting mode. The two-photon absorption nature in the parent benzothiadiazole–triphenylamine chromophore is maintained in the self-assembled system.

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