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Abstract A new oligothiophene functionalized Schiff base sensor 3TDC has been successfully designed and synthesized. Sensor 3TDC exhibited "naked-eye" colorimetric and selective "on-off" fluorescence response toward Cu2+ with high selectivity and sensitivity within a wide pH range. The binding ratio of the sensor 3TDC and Cu2+ was determined to be 1:1 through fluorescence titration, Job's plot, 1H NMR titration, FTIR and DFT studies. The detection limit is calculated to be as low as 2.81 × 10−8 M, which is much lower than the allowable level of Cu2+ in drinking water set by U.S. Environmental Protection Agency (~20 μM) and the World Health Organization (~30 μM). The binding constant (K a) of Cu2+ to sensor 3TDC was found to be 2.52 × 104 M−1. Sensor 3TDC for Cu2+ detection exhibited fast fluorescence response within 30 s and high anti-interference performance. Moreover, sensor 3TDC could be used as an effective fluorescent sensor for detecting Cu2+ ions in various real water and food samples with good accuracy and high precision. Graphical Abstract Unlabelled Image Highlights • Novel oligothiophene Schiff-base as naked-eye colorimetric and fluorescent sensor 3TDC has been synthesized. • Sensor 3TDC displayed highly selective and sensitive fluorescence sensing for Cu2+ within wide pH range. • Sensor 3TDC for Cu2+ showed high anti-interference ability and instantaneous response time. • Sensor 3TDC has been applied to detect trace amounts of Cu2+ in real water and food samples. [ABSTRACT FROM AUTHOR]

Developing low-cost and efficient sensors for rapid, selective and sensitive detection of the transition metal ions in environmental and food science is very important. In this study, a novel dual-functional fluorescent “turn-on” sensor 3TP based on oligothiophene-phenylamine Schiff base has been synthesized for discrimination and simultaneous detection of both Al 3+ and Fe 3+ ions with high selectivity and anti-interference over other metal ions. Sensor 3TP displayed a very fast fluorescence-enhanced response towards Al 3+ and Fe 3+ ions with low detection limits (0.177 μM for Al 3+ and 0.172 μM for Fe 3+ ) and wide pH response range (4.0–12.0). The Al 3+ /Fe 3+ sensing mechanisms were investigated by fluorescence experiments, 1 H NMR titrations, FT-IR and ESI-MS spectra. Importantly, sensor 3TP was served as an efficient solid material for the highly sensitive and selective detection of Fe 3+ on TLC plates. Moreover, the sensor 3TP has been successfully used to detect trace Al 3+ and Fe 3+ in environment and food samples with satisfactory results and good recoveries, revealing a convenient, reliable and accurate method for Al 3+ and Fe 3+ analysis in real samples. [ABSTRACT FROM AUTHOR]

A simple, reversible, colorimetric and water-soluble fluorescent chemosensor ADA for the naked-eye detection of Cu 2 + was developed. Sensor ADA showed high selectivity and sensitivity toward Cu 2 + in ~ 100% aqueous media over wide pH range. Sensor ADA exhibited a red-shift in the absorption spectra from 466 to 480 nm that is accompanied by significant color change from light yellow to yellowish brown instantaneously. The Cu 2 + recognition is based on the chelation–enhanced fluorescence quenching (CHEQ) effect of the paramagnetic nature. The lowest detection limit is determined to be 15.8 nM, which is much lower than the allowable level of Cu 2 + in drinking water set by U.S. Environmental Protection Agency (~ 20 μM) and the World Health Organization (~ 30 μM). The 1:1 binding process was confirmed by fluorescence measurements, IR analysis and DFT studies. Moreover, sensor ADA was successfully applied for determination of trace level of Cu 2 + with 4 reuse cycles in various water samples, which affords promising potential in ion-detection field. [ABSTRACT FROM AUTHOR]

A novel linear A-π-D-π-A-type organic small molecule Ph2(PDPP) 2 consisting diketopyrrolopyrrole (DPP) as acceptor unit, biphenylene as donor unit and acetylene unit as π-linkage has been successfully designed and synthesized. Its corresponding thermal, photophysical and electrochemical properties as well as the photoinduced charge-separation process were investigated. Ph2(PDPP) 2 exhibits high thermal stability and it can be soluble in common organic solvents such as chloroform and tetrahydrofuran. The photophysical properties show that DPP 2 Ph 2 harvests sunlight over the entire visible spectrum range in the thin-film state (300–800 nm). DPP 2 Ph 2 has lower band gaps and appropriate energy levels to satisfy the requirement of solution-processable organic solar cells. The efficient photoinduced charge separation process was clearly observed between DPP 2 Ph 2 with PC 61 BM and the K sv value was found to be as high as 2.13 × 10 4 M − 1 . Therefore, these excellent properties demonstrate that the designed A-π-D-π-A-type small molecule Ph2(PDPP) 2 is the prospective candidate as donor material for organic photovoltaic material. [ABSTRACT FROM AUTHOR]

A phenylamine-oligothiophene-based fluorescent sensor 2TBEA was reported. This sensor exhibited highly selective, sensitive and rapid detection of Hg 2 + ion in THF/H 2 O (7/3, v/v) solution through fluorescence quenching. The detection was unaffected by the coexistence of other competitive metal cations including Na + , K + , Ag + , Ca 2 + , Fe 3 + , Al 3 + , Co 2 + , Cu 2 + , Ni 2 + , Zn 2 + , Pb 2 + , Cd 2 + , Fe 2 + and Cr 3 + . A1:1 binding ratio for 2TBEA — Hg 2 + was demonstrated by Job's plot and mole-ratio curves. The coordination process was chemically reversible with EDTA. The detection limit was evaluated to be as low as 6.164 × 10 − 8 M. [ABSTRACT FROM AUTHOR]

A fast-responsive fluorescent phenylamine-oligothiophene sensor 3TDDA was reported. This sensor exhibited highly selective and sensitive detection of Hg 2 + ion in aqueous solution (THF/CH 3 CN/H 2 O, 45/50/5, v/v) through fluorescence quenching. The detection was not affected by the coexistence of other competitive metal ions such as Na + , K + , Ag + , Ca 2 + , Fe 3 + , Al 3 + , Co 2 + , Ni 2 + , Zn 2 + , Pb 2 + , Cd 2 + , Fe 2 + and Cr 3 + . A stoichiometric ratio (1:1) of the sensor and Hg 2 + was determined by a Job's plot and mole-ratio curves. The binding of sensor 3TDDA and Hg 2 + was also chemically reversible with EDTA. The detection limit was calculated as low as 4.392 × 10 − 7 M. [ABSTRACT FROM AUTHOR]

Abstract: Three novel planar and star-shaped molecules containing thiophene-functionalized group and acetylenic spacers, 4-((5″-iodo-[2,2′:5′,2″-terthiophen]-5-yl)ethynyl)aniline (I3TEA), 4,4′-([2,2′:5′,2″-terthiophene]-5,5″-diylbis(ethyne-2,1-diyl))dianiline (3TDDA), 1,3,5-tris((5-((trimethylsilyl)ethynyl)thiophen-2-yl)ethynyl)benzene (TETEB) were synthesized through Sonogashira coupling reaction. Their photophysical and electrochemical properties were explored by UV–vis, photoluminescence (PL) emission and DFT calculation. Three compounds possess unusual phenomena of PL, with the concentration of gradually decreased, the intensity of PL firstly increased and then decreased, this may be due to the aggregate-enhanced emission (AEE) effect and aggregation-caused quenching (ACQ) effect. Their spectroscopic data demonstrate that D–π–A–π–D structured organic dye 3TDDA based on NH2 as donor units and 3T as acceptor units with acetylenic spacers π-conjugated chain between them exhibits good luminescent properties. Dye I3TEA with donor(D)–acceptor(A) structure shows good charge transfer because of amino functional group and iodine atom. Octupolar organic π-conjugated star-shaped molecule TETEB possesses excellent luminescent properties because of its unique structure applied in the optoelectronic field. The redox curves and results of DFT calculations suggest that three compounds have low ionization potential and low E oxd. All the good properties demonstrate three compounds could be promising candidates for photovoltaic materials. [Copyright &y& Elsevier]

Using Hg2+-promoted deprotection reaction, we have developed a new fluorescent turn-on sensor 2TS based on bithiophene fluorophore for Hg2+ detection. The sensing mechanism of 2TS towards Hg2+ was strongly proved by 1H NMR, FTIR, HRMS, UV–vis and fluorescence spectra. Remarkly, 2TS towards Hg2+ in 100% aqueous solution shows high sensitivity with a low detection limit of 19 nM, superior selectivity and ultra-rapid response of 20 s during a wide sensing pH range from 4 to 10. Taking advantage of the excellent properties, the low-cost sensor 2TS -based filter paper/TLC test strips were fabricated for visual, immediate and quantitative detection of Hg2+ in water, proving its applicability towards sensitive in-situ and on-site detection. Meanwhile, 2TS showed high analytical performance for Hg2+ detection in water, seafood as well as human urine samples. Moreover, thanks to the good water solubility, negligible cytotoxicity, good biocompatibility and cell-membrane permeability, 2TS was further applied to effectively image Hg2+ in live cells. Furthermore, the developed sensor 2TS acted as good fluorescent display material for Hg2+ with obvious color change. Unlabelled Image • A new turn-on fluorescent sensor 2TS for Hg2+ in 100% aqueous solution was developed. • 2TS features good selectivity, ultra-sensitivity, ultra-rapid response towards Hg2+ in a wide sensing pH range. • 2TS was used to detect Hg2+ in water, seafood, human urine, test strips and living cells. • 2TS was used as fluorescent display material for conveniently detecting Hg2+. [ABSTRACT FROM AUTHOR]

A new simple and efficient fluorescent sensor L based on 1,8‑diaminonaphthalene Schiff-base for highly sensitive and selective determination of Cu 2+ in drink and water has been developed. This Cu 2+ -selective detection over other tested metal ions displayed an obvious color change from blue to colorless easily detected by naked eye. The detection limit is determined to be as low as 13.2 nM and the response time is very fast within 30 s. The 1:1 binding mechanism was well confirmed by fluorescence measurements, IR analysis and DFT calculations. Importantly, this sensor L was employed for quick detection of Cu 2+ in drink and environmental water samples with satisfactory results, providing a simple, rapid, reliable and feasible Cu 2+ -sensing method. [ABSTRACT FROM AUTHOR]

An oligothiophene-based colorimetric and ratiometric fluorescence dual-channel cyanide chemosensor 3 T-2CN was reported. Sensor 3 T-2CN showed both naked-eye recognition and ratiometric fluorescence response for CN − with an excellent selectivity and high sensitivity. The sensing mechanism based on the nucleophilic attack of CN − on the vinyl C C bond has been successfully confirmed by the optical measurements, 1 H NMR titration, FT-IR spectra as well as the DFT/TD-DFT calculations. Moreover, the detection limit was calculated to be 0.19 μM, which is much lower than the maximum permission concentration in drinking water (1.9 μM). Importantly, test strips (filter paper and TLC plates) containing 3 T-2CN were fabricated, which could act as a practical and efficient solid state optical sensor for CN − in field measurements. [ABSTRACT FROM AUTHOR]

A novel dual-responsive colorimetric and fluorescent chemosensor L based on diketopyrrolopyrrole derivative for Fe 3 + detection was designed and synthesized. In presence of Fe 3 + , sensor L displayed strong colorimetric response as amaranth to rose pink and significant fluorescence enhancement and chromogenic change, which served as a naked-eye indicator by an obvious color change from purple to red. The binding constant for L -Fe 3 + complex was found as 2.4 × 10 4 with the lower detection limit of 14.3 nM. The sensing mechanism was investigated in detail by fluorescence measurements, IR and 1 H NMR spectra. Sensor L for Fe 3 + detection also exhibited high anti-interference performance, good reversibility, wide pH response range and instantaneous response time. Furthermore, the sensor L has been used to quantify Fe 3 + ions in practical water samples with good recovery. [ABSTRACT FROM AUTHOR]

A new thiophene hydrazide derivative TSB was synthesized and utilized as naked-eye colorimetric sensor for Cu2+ by the color changed from colorless to yellow as well as green fluorescent turn on sensor for Al3+ in DMSO/H 2 O (1/1, V /V) solution. The dual-functional chemosensor TSB for Cu2+/Al3+ sensing displayed excellent properties of special selectivity, superior sensitivity, outstanding anti-interference performance, instantaneous response, wide pH working range and good reversibility. The detection limits of TSB for Cu2+/Al3+ were determined as low as 46.5 nM and 32.7 nM, respectively. The 1:1 binding mode of TSB with Cu2+/Al3+ was proved by spectrometric titrations, Job's plots, FTIR, 1H NMR and HRMS analysis. Moreover, chemosensor TSB was successfully utilized for detection of Cu2+ and Al3+ in real environmental water and food samples with high reliability, demonstrating its practical applicability. Unlabelled Image • A new thiophene-hydrazide based colorimetric and fluorescent sensor TSB was synthesized. • The dual-functional sensor TSB shows colorimetric response to Cu2+ and fluorimetric response to Al3+. • The low detection limits of TSB for Cu2+/Al3+ were determined to be 46.5 nM and 32.7 nM. • TSB was utilized for detecting Cu2+/Al3+ in environmental water and food samples with high reliability. [ABSTRACT FROM AUTHOR]