This paper reports the first fluorescent sensor for medium-chain fatty acids in water. The hybrid sensing material (S2) was prepared by the reaction of a rationally designed “recognition center”, N-butyl-4-piperazin-1,8-naphthalimide, with a 3-glycidoxypropyl group which is pre-grafted on the interior of a mesoporous solid (MCM-41). The organo-functionalization of the mesoporous solid (MCM-41) was confirmed by FT-IR, 29Si MAS NMR and elemental analysis. The results of XRD, N2 physical adsorption–desorption, SEM and TEM studies proved that the organized structure of the nanoscopic porous solid is preserved after the reactions. The fatty acid-selective signaling behavior of S2 was investigated in water at pH = 5.80/7.16/8.00. This material displays much stronger fluorescence enhancement with C8–C12 fatty acids than with the shorter and longer chains in aqueous media, both in the absence and in the presence of aromatic acids.

Three isomeric fluorescent β-cyclodextrins bearing 2-, 3-, and 4-(2-aminoethyl)amino-N-butylbenzamide, respectively (1–3) have been synthesized. The conformations of these fluorescent CDs have been investigated by 2D NMR and induced circular dichromism. It is confirmed that the ortho isomer 1 takes a butyl-included conformation, while the other two isomers 2 and 3 display a phenyl-included conformation, respectively. The three fluorescent CDs 1–3 exhibited totally different self- and guest-inclusion fluorescence behavior. In the presence of adamantane carboxylate sodium (ADA) or deoxycholate sodium (DCA), the fluorescence intensity of 1 showed an enhancement over 1-fold, while 2 exhibited dramatic fluorescence quenching. Interestingly, the fluorescent responses of 3 toward two guests respectively were highly distinguishable. The fluorescence intensity of 3 only showed a slight increase upon the addition of ADA, but the addition of DCA led to a large decrease in fluorescence intensity. The investigations have been further carried out by 2D NMR, induced circular dichromism, fluorescence spectroscopy and molecular modeling to explore the relationships between the conformations and the fluorescence characteristics of CDs 1–3 in the absence and presence of guest molecules. On the basis of the above investigations, the origins for the different fluorescence behaviors have been proposed.

A new fluorescent cyclodextrin shows unexpected and strong fluorescence enhancement upon binding of organic molecules, and the enhancing mechanism is found to be different from those reported in the literature.

A fluorescent chemodosimeter containing a guanidiniocarbonylpyrrole and a 9-(aminomethyl)anthracene moiety has been synthesized. The sensor exhibits ratiometric fluorescence changes for SO32− over other anions in 90% water/DMSO. The interesting ratiometric fluorescent changes for SO32− are attributed to the fluorescence resonance energy transfer (FRET) and the SO32− complex induced photochemical reaction.

A new 4-amino-1,8-naphthalimide-based fluorescent chemosensor bearing a guanidiniocarbonyl pyrrole moiety has been synthesized. The sensor displays a selective fluorescent enhancement with pyrophosphate over ATP, ADP, AMP and other inorganic anions in aqueous solution.

An intramolecular charge transfer (ICT) fluorescent probe, in which the thiourea derivative moiety is linked to the fluorescent 4-(dimethylamino) benzamide, has been designed and synthesized. The ions-selective signaling behaviors of the probe were investigated. Upon the addition of Ag+, an overall emission enhancement of 14-fold was observed. Compound 1 displayed highly selective chelation enhanced fluorescence (CHEF) effect with Ag+ over alkali, alkali earth metal ions and some transition metal ions in aqueous methanol solutions. The prominent selective and efficient fluorescent enhancing behavior could be utilized as a new chemosensing probe for the analysis of Ag+ ion in aqueous environment.

A series of new compounds, (1R,2R)-1-(1′,8′-naphthalimide)-2-aminocyclohexane 1 and its 4′-derivatives 2 and 3 derived from (1R,2R)-1,2-diaminocyclohexane have been synthesized conveniently and efficiently. 1H NMR spectroscopy was employed to investigate their enantiodiscriminating ability. Compared with α-phenylethylamine, a commercially available chiral solvating agent (CSA), these compounds exhibited better enantiodiscriminating ability toward the chiral carboxylic acids we had chosen, distinguishing them as promising and practical CSAs.(1R,2R)-1-(1′,8′-Naphthalimide)-2-aminocyclohexane and its 4′-derivatives derived from (1R,2R)-diaminocyclohexane are efficient NMR chiral solvating agents for chiral carboxylic acids leading to large separation (ΔΔδ up to 104.1 Hz) of the proton signals of the enantiomers.(1R,2R)-1-(1′,8′-Naphthalimide)-2-aminocyclohexaneC18H18N2O2Ee 100%[α]D20=+2.3 (c 2.50, CHCl3)Source of chirality: (1R,2R)-1,2-diaminocyclohexaneAbsolute configuration: (1R,2R)(1R,2R)-1-(4′-Bromo-1′,8′-naphthalimide)-2-aminocyclohexaneC18H17BrN2O2Ee 100%[α]D20=-12.8 (c 0.065, CHCl3)Source of chirality: (1R,2R)-1,2-diaminocyclohexaneAbsolute configuration: (1R,2R)(1R,2R)-1-(4′-Dimethylamino-1′,8′-naphthalimide)-2-aminocyclohexaneC20H23N3O2Ee 100%[α]D20=-16.0 (c 0.025, CHCl3)Source of chirality: (1R,2R)-1,2-diaminocyclohexaneAbsolute configuration: (1R,2R)

A new 4-amino-1,8-naphthalimide-based fluorescent chemosensor bearing a guanidiniocarbonyl pyrrole moiety has been synthesized. The sensor displays a selective fluorescent enhancement with pyrophosphate over ATP, ADP, AMP and other inorganic anions in aqueous solution.

A new fluorescent cyclodextrin shows unexpected and strong fluorescence enhancement upon binding of organic molecules, and the enhancing mechanism is found to be different from those reported in the literature.

This paper reports the first fluorescent sensor for medium-chain fatty acids in water. The hybrid sensing material (S2) was prepared by the reaction of a rationally designed “recognition center”, N-butyl-4-piperazin-1,8-naphthalimide, with a 3-glycidoxypropyl group which is pre-grafted on the interior of a mesoporous solid (MCM-41). The organo-functionalization of the mesoporous solid (MCM-41) was confirmed by FT-IR, 29Si MAS NMR and elemental analysis. The results of XRD, N2 physical adsorption–desorption, SEM and TEM studies proved that the organized structure of the nanoscopic porous solid is preserved after the reactions. The fatty acid-selective signaling behavior of S2 was investigated in water at pH = 5.80/7.16/8.00. This material displays much stronger fluorescence enhancement with C8–C12 fatty acids than with the shorter and longer chains in aqueous media, both in the absence and in the presence of aromatic acids.