A novel halogen bonding (XB) donor–acceptor N-benzylideneaniline 3, containing one terminal of iodo-tetrafluorobenzene and the other side of 4-dimethylaminophenyl connected by a CN bond, has been designed and synthesized. As a self-assembled halogen-bonded motif, 3 exists in two conformations and they are antiparallel to generate fishbone-like stacks by π⋯π and C–I⋯π intermolecular interactions. As a halogen-bonded donor, it can connect with 4,4′-bipyridine to constitute 2 : 1 ratio cocrystal with C–I⋯NPy interactions. When the acceptor changes to 4-alkoxystilbazole, liquid crystal property varies with the length of the terminal chains. DSC and POM experiments demonstrated a series of XB liquid crystals. Among them, 3-A10 shows a long range of nematic phase and an integrated schlieren texture.

A novel solvatochromic fluorescent cyanostilbene derivative 1 with a D–π–A structure was synthesized. The introduction of an electron-donating methoxy group and an electron-accepting nitro group into the π-conjugated cyanostilbene bridge offered an intense intramolecular charge transfer (ICT) process in molecules and endowed 1 with a prominent solvatochromic emission property. Compared with the moderate changes in its absorption spectra in the different solvents, the emission of 1 was strongly dependent on the solvent polarity and could be tuned from blue to red by changing the solvent from apolar toluene to polar dichloromethane (DCM). Significantly, 1 can function as an efficient intensity and wavelength-based fluorescent sensor for the detection of trace water in THF and dioxane, respectively. A low detection limit of 71 ppm in THF made it a supersensitive water sensor for practical applications. A remarkable red shift of about 45 nm in dioxane made 1 an efficient wavelength-based fluorescent sensor for water avoiding external disturbance, whose emission color can be easily observed and distinguished by the naked eye. Moreover, the easy-to-prepare test papers loaded with 1 provide a simple and low cost protocol for the qualitative and quantitative detection of the water content in organic solvents without resorting to instrumental analysis.

Schiff base 1 (2,4-di-tert-butyl-6-((2-hydroxyphenyl-imino)-methyl)phenol) containing two hydroxyl groups could undergo an oxidative cyclization reaction and then generate hydroxyphenylbenzoxazole (HBO) 2 when CN− was present as a catalyst. The multistep cyclization reaction was proved by spectroscopy, 1H NMR, 13C NMR and mass spectra. CN isomerization is the predominant decay process of the excited states, so sensor 1 is weakly emissive in solution at ambient temperature. When 1 reacts with CN−, the emission is remarkably enhanced, where 1 is converted to 2. The cyclization product HBO 2 displays bright green luminescence in micellar due to the ESIPT (excited-state intramolecular proton transfer) as well as AIEE (aggregation-induced emission enhancement) effect. The detection limit is 5.92 × 10−7 M, lower than the WHO guideline of CN− in drinking water (1.9 μM). The selective and competitive experiments reveal that sensor 1 shows high sensing selectivity and sensitivity for CN− over other anions. Test papers containing absorbed 1 were prepared and applied for practical application of cyanide detection.

A highly selective and sensitive FRET ratiometric fluorescent nanosensor has been developed for detection Fe3+ in aqueous solution and on test papers. The sensor consisted of rhodamine 6G moieties covalently coupled onto the surface of CDs. It works based on a Fe3+-triggered FRET process between CDs and ring-opened rhodamine 6G.

A copolymer poly(NIPAM-co-RD) consisting of N-isopropylacrylamide (NIPAM) and N-tripodal rhodamine 6G units (RD) as the thermoresponsive and sensing parts, respectively, has been prepared. At room temperature, the copolymer is fully dissolved in water and it could be used as a highly sensitive and selective fluorescent sensor for Hg2+ in a wide range of pH from 5.0 to 10.0. The non-fluorescent copolymer showed a significant fluorescence enhancement in the presence of Hg2+ over other competitive metal ions. It works based on the Hg2+ induced ring-opening of the rhodamine units. The detection limit was as low as 2.25 × 10−8 M. Upon heating above the lower critical solution temperature (LCST), the copolymer may collapse and form aggregates, therefore the copolymer containing Hg2+ could be separated from water by centrifugation at high temperature. In addition, the separated copolymer with Hg2+ could be treated by sodium sulfide, and the original copolymer was successfully regenerated and then reused for further Hg2+ sensing.

Correction for ‘An efficient phase-selective gelator for aromatic solvents recovery based on a cyanostilbene amide derivative’ by Yuping Zhang et al., Soft Matter, 2015, 11, 5095–5100.

Two novel low molecular weight organogelators (LMOGs) 1 and 2 composed of a cholesteryl group, an amide group and various terminal cyanostilbene moieties were synthesized. They could form stable gels in p-xylene. In particular, 2 with more extended π-conjugation length showed remarkable gelation ability in many aromatic solvents, chloroform and chloroform-containing mixed solvents at a relatively low concentration. FT-IR and XRD spectra indicated that the difference between 1 and 2 in the gelation properties may result from the deviation of the intermolecular hydrogen bonding and π–π stacking as driving forces for the formation of the gels. Significantly, 2 can function as an efficient room-temperature phase-selective gelator (PSG) for potential application in the separation and recovery of various aromatic solvents from its mixture with water. Meanwhile, the gelator can be easily recovered and reused several times. Furthermore, the phase-selective gelation properties of 2 can provide a simple and feasible approach for the removal of the rhodamine B (RhB) dye from water.

An “off-the-shelf” fluorescence “turn-on” Mg2+ chemosensor 3,5-dichlorosalicylaldehyde (BCSA) was rationally designed and developed. This proposed sensor works based on Mg2+-induced formation of the 2:1 BCSA–Mg2+ complex. The coordination of BCSA to Mg2+ increases its structural rigidity generating a chelation-enhanced fluorescence (CHEF) effect which was confirmed by single crystal XRD studies of the BCSA–Mg2+ complex and TD/DFT calculations. This sensor exhibits high sensitivity and selectivity for the quantitative monitoring of Mg2+ with a wide detection range (0–40 μM), a low detection limit (2.89 × 10−7 mol L−1) and a short response time (<0.5 s). It can also resist the interference from the other co-existing metal ions, especially Ca2+. Consequently, this fluorescent sensor can be utilized to monitor Mg2+ in real time within actual samples from drinking water.

An easy-to-make salicylimine (L) bearing an “O–N–O”-coordination site was used as a highly selective fluorescent sensor for Al3+ and PPi in aqueous solution. Sensor L showed a significant fluorescence enhancement in the presence of Al3+ over other competitive metal ions. It works based on the Al3+-induced formation of a 1:1 L–Al3+ complex, producing a chelation-enhanced fluorescence effect, the fluorescence quantum yield reached 0.59. This L–Al3+ ensemble is a subsequent fluorescent sensor for PPi due to the strong attraction between Al3+ and PPi, it can selectively discriminate PPi overcoming the interference of the biological competitors including PO43−, ADP and ATP at physiological pH. L and L–Al3+ exhibit high sensitivity and selectivity for Al3+ and PPi, the detection limits were found to be as low as 2.94 × 10−8 M and 2.74 × 10−7 M, respectively. It was further confirmed that sensor L had potential practical applications through mapping of Al3+ in live cells.

An intensely fluorescent zinc-salicylideneimine complex (1-Zn(II)) was developed as a fluorescent ratiometric detector for the quantitative determination of trace water contents both in THF and methanol. It works based on a water-triggered cascade process: the dissociation reaction of the supramolecular ensemble and the subsequent hydrolysis reaction of its ligand.

A V-shaped cyanostilbene amide derivative (BPBIA) containing tert-butyl groups has been designed and synthesized. It was employed as building blocks to fabricate one-dimensional (1D) organic nano- or microstructures. BPBIA shows excellent self-assembling properties. First, it can readily self-assemble into gels with nanofiber structures in several kinds of organic solvents through the cooperative effect of intermolecular hydrogen bonding, π–π stacking and cyano interactions. Second, size controllable well-defined 1D nanowires with lengths up to several millimeters also have been fabricated based on the slow evaporation approach. More importantly, the individually dispersed nanowires with uniform morphology are independent of substrates and solvents. Compared with the solution, both the generated nanofibrous gels and the nanowires exhibited significantly enhanced emission, showing typical aggregation-induced emission (AIE) behavior. The single-crystal X-ray analysis provided a reasonable explanation for the formation of 1D nano- or microstructures. Thus, the molecule could provide ways for the easy fabrication of highly emissive nano- and microstructures for use in organic optoelectronics.

A novel 3-5-dichlorosalicylaldehyde Schiff base chemodosimeter (compound 1) for water is designed and synthesized, and it works based on a water-triggered reaction of a Schiff base. Addition of trace amounts of water into 1 in various organic solvents leads to a fluorescence turn-on response and a simultaneous dual-channel signal modulation (both in the fluorescence and absorption spectra). Especially, 1 is found to be an outstanding fluorescence enhancement water sensor in methanol with an extremely low detection limit of 22 ppm. Consequently this probe can be utilized to detect trace water in commercial methanol. The quantitative detection of a wide range of water content is enhanced in THF and acetonitrile (0–35% v/v for THF and 0–20% v/v for acetonitrile), where the fluorescence peak intensity is nearly proportional to the amount of water added. Moreover, 1 can be used for monitoring pH through a novel ON–OFF–ON type signal modulation both in fluorescence and absorption spectra within a wide pH detection range. Thus, the chemodosimeter can not only be utilized to monitor the intracellular pH fluctuations, but also to accomplish simultaneous in situ staining of the cytosol and acidic organelles in two different channels, respectively.

A cholesterol-based salicylidene Schiff base derivative CDBHA (cholesterol 2-(3,5-di-tert-butyl-2-hydroxybenzylideneamino)acetate) with excellent multi-stimuli-responsive properties has been designed and synthesized. CDBHA can readily self-assemble into gels with nanofiber structures in several kinds of organic solvents. Compared to their corresponding solutions, the generated gels exhibited a significantly enhanced emission. This typical aggregation-induced emission (AIE) property is a result of the cooperative formation of the J-aggregates and inhibition of the intramolecular rotation. In addition, CDBHA gels are intelligent. On one hand, gel–sol transitions together with noticeable fluorescence changes can be reversibly modulated by alternating rounds of cooling and heating. On the other hand, the gels show a highly selective dual-responsive behavior to Zn2+ through a gel–sol transition, a turn-on of fluorescence and an efficient dual-responsive behavior to F− through gel–sol transition and color changes.

A new and easy-to-prepare gelator based on cyano-substituted amide (BPNIA) was designed and synthesized. BPNIA could form thermoreversible gel in DMSO–H2O (v/v, 9:1) and ultrasound-stimulated gel in DMSO. FT-IR, UV–vis and XRD spectra indicated that the gelator molecules self-assemble into a fibrous network resulting from the cooperation of intermolecular hydrogen bonding, π–π stacking and cyano interactions. BPNIA can act as a highly selective colorimetric sensor for fluoride in DMSO, overcoming the interference of H2PO4−, AcO− and other halide anions. The deprotonation of the NH groups is responsible for the dramatic color change from colorless to yellow. Interestingly, the organogel of BPNIA could allow a two channel fluoride response by proton controlled reversible sol–gel transition and color changes.

Highly ordered iron oxide nanoparticles with controlled size and spacing over a large surface area were prepared with polystyrene-block-poly(2-vinyl pyridine) (PS-b-P2VP) diblock copolymer template, the obtained nanoparticles could be used as catalysts for CNTs growth in a plasma-enhanced chemical vapor deposition (PECVD) system. This route offers the capability of controlling the density of CNTs on the substrate by altering the growing time, and aligned CNTs grew vertically onto the substrates with a pre-coating of aluminium oxide (Al2O3) layer. In addition, Au nanoparticles were successfully attached to the sidewall of deposited CNTs through in situ synthetic method.

The 2,2′-bis(3,5-dichloro-2-hydroxybenzylideneamino)-1,1′-binaphthyl salen-type Schiff base (BCHB) has been synthesized and characterized. Exhibiting absorption and fluorescence changes in the presence of Cu2+ and Zn2+ in tetrahydrofuran (THF) solution, BCHB could be used as a colorimetric ‘naked eye’ and fluorescent chemosensor for the detection of Cu2+ and Zn2+ bi-functionally. Furthermore, this organic ligand can selectively recognize Cu2+ and Zn2+ in the presence of other metal ions (such as Na+, Ag+, Mn2+, Co2+, Ni2+, Fe3+, Cd2+, Hg2+, Pb2+, La3+, and Nd3+), respectively. On the other hand, BCHB presents a tunable system integrated with one OR logic gate as well as one INHIBIT logic gate with Zn2+ and Cu2+ as chemical inputs by monitoring fluorescence and absorbance as output signals. Also, one IMPLICATION gate operating in fluorescence mode with Cu2+ and EDTA as chemical inputs, based on their different binding capabilities, is present in this system.

The salen-type Schiff base (2,2′-bis(2-hydroxybenzylideneamino)-1,1′-binaphthyl (BHB)) has been synthesized and characterized. Exhibiting absorption and fluorescence changes in the presence of Zn2+ in chloroform and ethanol mixed solution, BHB could be used as a fluorescent chemosensor for the detection of Zn2+. Furthermore, by monitoring the fluorescence and absorbance as output signals, BHB can function as a combinatorial logic circuit for a molecular half-subtractor with Zn2+ and UV irradiation as input variables.

A new symmetric bi-pyridyl banana-shaped molecule 1,3-phenylene diisonicotinate (PDI) was designed and synthesized. Its molecular structure was confirmed by FTIR, Elemental analysis and 1H NMR. X-ray crystallographic study reveals that there is an angle of approximate 118° among the centroids of the three rings (pyridyl–phenyl–pyridyl) in each PDI molecule indicating a desired banana shape. In addition, a series of liquid crystal complexes nBA:PDI:nBA induced by intermolecular hydrogen bonding between PDI (proton acceptor) and 4-alkoxybenzoic acids (nBA, proton donor) were synthesized and characterized. The mesomorphism properties and optical textures of the complex of nBA:PDI:nBA were investigated by differential scanning calorimetry, polarizing optical microscope and X-ray diffraction.

A new and easy-to-prepare gelator based on cyano-substituted amide (BPNIA) was designed and synthesized. BPNIA could form thermoreversible gel in DMSO–H2O (v/v, 9:1) and ultrasound-stimulated gel in DMSO. FT-IR, UV–vis and XRD spectra indicated that the gelator molecules self-assemble into a fibrous network resulting from the cooperation of intermolecular hydrogen bonding, π–π stacking and cyano interactions. BPNIA can act as a highly selective colorimetric sensor for fluoride in DMSO, overcoming the interference of H2PO4−, AcO− and other halide anions. The deprotonation of the NH groups is responsible for the dramatic color change from colorless to yellow. Interestingly, the organogel of BPNIA could allow a two channel fluoride response by proton controlled reversible sol–gel transition and color changes.

A V-shaped cyanostilbene amide derivative (BPBIA) containing tert-butyl groups has been designed and synthesized. It was employed as building blocks to fabricate one-dimensional (1D) organic nano- or microstructures. BPBIA shows excellent self-assembling properties. First, it can readily self-assemble into gels with nanofiber structures in several kinds of organic solvents through the cooperative effect of intermolecular hydrogen bonding, π–π stacking and cyano interactions. Second, size controllable well-defined 1D nanowires with lengths up to several millimeters also have been fabricated based on the slow evaporation approach. More importantly, the individually dispersed nanowires with uniform morphology are independent of substrates and solvents. Compared with the solution, both the generated nanofibrous gels and the nanowires exhibited significantly enhanced emission, showing typical aggregation-induced emission (AIE) behavior. The single-crystal X-ray analysis provided a reasonable explanation for the formation of 1D nano- or microstructures. Thus, the molecule could provide ways for the easy fabrication of highly emissive nano- and microstructures for use in organic optoelectronics.

An “off-the-shelf” fluorescence “turn-on” Mg2+ chemosensor 3,5-dichlorosalicylaldehyde (BCSA) was rationally designed and developed. This proposed sensor works based on Mg2+-induced formation of the 2:1 BCSA–Mg2+ complex. The coordination of BCSA to Mg2+ increases its structural rigidity generating a chelation-enhanced fluorescence (CHEF) effect which was confirmed by single crystal XRD studies of the BCSA–Mg2+ complex and TD/DFT calculations. This sensor exhibits high sensitivity and selectivity for the quantitative monitoring of Mg2+ with a wide detection range (0–40 μM), a low detection limit (2.89 × 10−7 mol L−1) and a short response time (<0.5 s). It can also resist the interference from the other co-existing metal ions, especially Ca2+. Consequently, this fluorescent sensor can be utilized to monitor Mg2+ in real time within actual samples from drinking water.

In aromatic solvents, V-shaped bis-cyanostilbene derivative 1 forms stable and emissive gels which are capable of responding to light and, selectively, to TFA via a gel-to-sol transformation.

An easy-to-make salicylimine (L) bearing an “O–N–O”-coordination site was used as a highly selective fluorescent sensor for Al3+ and PPi in aqueous solution. Sensor L showed a significant fluorescence enhancement in the presence of Al3+ over other competitive metal ions. It works based on the Al3+-induced formation of a 1:1 L–Al3+ complex, producing a chelation-enhanced fluorescence effect, the fluorescence quantum yield reached 0.59. This L–Al3+ ensemble is a subsequent fluorescent sensor for PPi due to the strong attraction between Al3+ and PPi, it can selectively discriminate PPi overcoming the interference of the biological competitors including PO43−, ADP and ATP at physiological pH. L and L–Al3+ exhibit high sensitivity and selectivity for Al3+ and PPi, the detection limits were found to be as low as 2.94 × 10−8 M and 2.74 × 10−7 M, respectively. It was further confirmed that sensor L had potential practical applications through mapping of Al3+ in live cells.