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Abstract: The sequential excitation energy transfer has been studied in a C16Naph(2,6)C4N+, titan yellow (TY) and fluorescein sodium (FS) ternary aqueous covesicle system. The sequential arrays of chromophores with regulated distance, orders, and orientations were constructed on a non-covalent self-organization system through amphiphilic and electrostatic interaction in aqueous media. The naphthalene group, embedded in the interior of the vesicles, TY and FS anchored on surface of the covesicles through electrostatic interaction, which were employed as donor, mediator and acceptor, respectively, based on overlapping absorption and emission spectra. The sequential energy transfer from naphthalene cascading through TY mediator to FS has been studied in the C16Naph(2,6)C4N+, TY and FS ternary aqueous covesicle system. This sequential excitation energy transfer offers a good model for photoenergy transmission system mimicking photosynthetic systems. [Copyright &y& Elsevier]

Abstract: A single chain synthetic amphiphile, 4-(5-dodecyloxynaphthalene-1-oxy) butyl trimethylammonium bromide (C12Naph(1,5)C4N+), can be self-assembled into vesicles in the dilute aqueous solution and subsequently form excimer in the vesicles. The excitation energy transfer has been performed in the C12Naph(1,5)C4N+ aqueous vesicles. The donor, naphthalene group, was embedded in the interior of the vesicles. The acceptor, titan yellow, with two negatively charged polar groups, was bound electrostatically to the positively charged surface of vesicles. The energy transfer efficiency increased with the increase of the concentration of titan yellow acceptor in the range of 0–1.2×10−5 moldm−3. Titan yellow quenched the fluorescence intensity of the naphthalene, which fitted a Stern–Volmer plot, and the Stern–Volmer quenching constant K sv is 1.75×104 dm3 mol−1. [Copyright &y& Elsevier]

A novel fluorescent compound Tetra((4-bis(2-hydroxyethyl)amino)methyl phenyl)ethene (3) was synthesized and employed as a fluorogenic probe for detecting Hg2+. This probe exhibits low fluorescence in aqueous environment, which can be enhanced in the presence of Hg2+ due to the complexation between 3 and Hg2+. Furthermore, the fluorescence intensity of 3 can be further enhanced upon addition of lipopolysaccharide (LPS), because the binding between 3 -Hg2+ and LPS activate the aggregation-induced emission (AIE) property of compound 3. Therefore, this fluorescence probe is employed as a fluorescent marker to monitor the interaction between Hg2+ and gram-negative bacteria. The biosorption capacity for Hg2+ of gram-negative bacteria is evaluated conveniently by the fluorescence intensity change of compound 3. [Display omitted] • A novel fluorescence probe for Hg2+ is designed and successfully synthesized. • The probe exhibit high selective recognition for Hg2+ in aqueous solution. • The probe can be used as a fluorescent marker to monitor the interaction between LPS and Hg2+. • The fluorescent marker can be used to evaluate the biosorption capacity for Hg2+ of gram-negative bacteria. [ABSTRACT FROM AUTHOR]

A single chain synthetic amphiphile, 4-(2-hexadecyloxynaphthalene-6-oxy)butyl trimethylammonium bromide (C16Naph(2,6)C4N+), can self-assemble into vesicles in the dilute solution. The fluorescence resonance energy transfer has been studied in aqueous vesicle solution of C12Naph(1,5)C4N+ and hydrophilic dye fluorescein sodium salt (FS). The donor, naphthalene group, was embedded in the interior of the vesicles. The acceptor, FS with two negatively charged polar groups, was bound electrostatically to the positively charged surface of (C16Naph(2,6)C4N+) vesicles. The FS quenched the fluorescence intensity of the naphthalene, which fitted a Stern–Volmer plot, and the Stern–Volmer quenching-constant K sv is 5.65×105 mol−1. The energy transfer efficiency increased with the increasing concentration of FS acceptor in the range of 0–4.4×10−6 dm3 mol−1 up to ca. 71% which could be ascribed to the ordered arrangement of chromophores inside the vesicles. [Copyright &y& Elsevier]

A polyhydroxy benzoylhydrazone-based low-molecular-weight organic gelator (IV 1) containing a tetraphenylethene fluorophore was designed and synthesized. Gelator IV 1 exhibits exceptional gelation ability in organic solvent comparing to other analogues. More importantly, the time-dependent increase of storage modulus G′ of the gel and fluorescent intensity of IV 1 are almost synchronized, which indicates that the gelation process and fluorescence enhancement are extremely relevant. This provides a convenient method to visually monitor the gelation process of organic gelators by fluorescent detection. Furthermore, gelation mechanism is studied in detail. According to these results, we propose the intermolecular interactive mechanism to understand the gelation process of polyhydroxy benzoylhydrazone-based tetraphenylethene compounds. Image 1 • AIE fluorogen was implanted into the gelator. • Gelation process and fluorescence enhancement were synchronized. • Gelation process was tracked in situ and in real time by fluorescence signal. [ABSTRACT FROM AUTHOR]

A tetraphenylethene (TPE) derivative tetra(3-1 H -benzo[ d ]imidazol-2-yl) -4-hydroxyphenyl)ethene (TBIHPE) which exhibits crystallization-induced emission enhancement (CIEE) induced by tetrahydrofuran (THF) and reversible fluorescence shifting upon HCl fuming and heating or NH 3 fuming was prepared. The CIEE and reversible fluorescence shift process were controlled by imino group and tertiary amine group of 2-(2′-Hydroxyphenyl)benzimidazole (HBI) moiety, respectively. The intermolecular hydrogen bonds between THF and imino group have been observed by single-crystal X-ray structural analysis, which changed the excited-state intramolecular proton transfer (ESIPT) process of TBIHPE, and induced the CIEE phenomena. The fluorescence emission peak of TBIHPE shows blue shift upon HCl fuming stimuli in solid state. Moreover, the fluorescence emission of HCl fumed TBIHPE solid can recover by heating or fuming in NH 3 vapors. Based on the results, the relationship between photophysical properties and protonation-deprotonation stimuli was discussed. Image 1 • We synthesized a novel tetraphenylethene derivative TBIHPE. • TBIHPE was found to be AEE-active. • TBIHPE exhibited CIEE properties. • The fluorescence emission of TBIHPE could be shifted by external stimuli. [ABSTRACT FROM AUTHOR]