A chemodosimer based on a core-substituted naphthalene diimide for fluoride ion detection

Theoretical investigation of naphthodithiophene diimide derivatives as fluorescent sensors for 2,4,6-trinitrophenol detection

CONTEXT

This study explored the geometry, aromaticity, electrostatic potential, and fluorescence sensing capability of N,N'-dimethyl naphthodithiophene diimide (C1-NDTI-S) and its derivatives (C1-NDFI-O and C1-NDPI-N), where thiophene rings were substituted with furan and pyrrole, respectively. Theoretical calculations revealed that C1-NDTI-S had the most negative adsorption energy for 2,4,6-trinitrophenol (TNP), and its electronic absorption spectrum and fluorescence spectrum decreased considerably upon TNP adsorption. Through FMO, hole-electron, independent gradient model, and energy decomposition analysis, it was revealed that the essence of fluorescence quenching is the intermolecular weak π-π interaction driving photo-induced electron transfer. Furthermore, C1-NDFI-O and C1-NDPI-N generated by modifying the structure of C1-NDTI-S have the potential to serve as more efficient fluorescent sensors for TNP detection. The fluorescence recovery times confirmed the suitability of the three compounds as fluorescence probes.

METHODS

In this study, the Gaussian 09 software package at B3LYP-D3(BJ)/6-311 +  + G** level was applied to optimize the structure, energy, and fluorescence recovery time. Multiwfn combined with VMD software package was used to analyze the aromaticity of compounds using LOL-π and HOMA, with a focus on the differences in aromaticity after thiophene was substituted with different rings. Using AMBER force field for energy decomposition analysis based on force field (EDA-FF), the weak intermolecular interaction components are decomposed. The independent gradient model analysis based on Hirshfeld partition analysis clearly demonstrates the π-π interactions between molecules, with the δginter parameter set to 0.005 a.u. Electron absorption spectroscopy, charge-transfer spectra spectroscopy, molecular interactions, and hole electron interactions were all completed with the help of Multifwn software.

A New 'Off-On' System Based on Core-Substituted Naphthalene Diimide with Dimethylamine for Reversible Acid-Base Sensing

A new 'Off-On' system designed and synthesised by functionalisation of a naphthalene diimide (NDI) core with dimethylamine produces 4,9-bis(dimethylamino)-2,7-dioctylbenzo[lmn][3,8]-phenanthroline-1,3,6,8-(2H,7H)-tetraone, abbreviated as DDPT (1). DDPT 1 was synthesised using a simple strategy, namely aromatic nucleophilic substitution using Br2 -NDI with dimethylamine at 110 °C. DDPT was characterized by 1 H and 13 C NMR spectroscopy, ESI mass spectrometry and elemental analysis. DDPT 1 was then used for optical studies through protonation of its dimethylamine core with trifluoroacetic acid (TFA), blue-shifting the absorption band from 600 nm to 545 nm in solution. Interestingly, the fluorescence of DDPT 1 is weak in solution with a quantum yield Φ=0.09, which is significantly enhanced to Φ=0.78 upon addition of TFA. The limit of detection (LOD) was determined to 2.77 nm. Furthermore, DDPT 1 can be used for naked eyed detection not only under UV light (365 nm) but also using visible light, as clear changes can be clearly seen upon addition of TFA. The binding constant of DDPT was calculated to 2.1×10-3  m-1 . Importantly, DDPT 1 showed reversible switching by alternative addition of acid (TFA) and base (triethylamine) without loss of activity. Immobilised on paper, DDPT 1 can be used for strip-test sensing in which the colour changes from blue to reddish when expose to TFA vapours and reverse in the presence of triethylamine vapours.

Rapid and visual detection of Cd2+ based on aza-BODIPY near infrared dye and its application in real and biological samples for environmental contamination screening

Cadmium highly toxic and hazardous, and it can adversely affect human health leading to serious disorders. Herein, a water-soluble near-infrared sensor based on aza-BODIPY (1) was developed for dual determination of Cd²⁺ in environmental and biological media. This sensor exhibited color change from colorless to green along with a fluorescence enhancement in the near-infrared (NIR) region via photoinduced electron transfer (PET) after complexation with Cd²⁺. Sensor 1 can be employed in aqueous media at physiological pH for quantitative monitoring. It shows rapid response with high sensitivity (detection limit of 2.8 ppb; linear correlation over [Cd²⁺] 1.33 - 6.67 µM) and selectivity over potentially interfering ions. NIR sensor 1 can be used to determine [Cd²⁺] in living cells and environmental samples.

Ratiometric sensing of fluoride ions using Raman spectroscopy

Ratiometric Raman spectroscopy represents a novel sensing approach for the detection of fluoride anions based on alkyne desilylation chemistry. This method enables rapid, anion selective and highly sensitive detection of fluoride in a simple paper-based assay format using a portable Raman spectrometer.

A Naphthalene Diimide Based Macrocycle Containing Quaternary Ammonium Groups: An Electron-Deficient Host for Aromatic Carboxylate Derivatives

Naphthalene diimide (NDI) compounds are widely used as electron acceptors in various applications. Herein, we combine NDI with quaternary ammonium groups for the synthesis of a highly electron-deficient linear compound 2 and macrocycle 3. The complexation studies of the water-soluble macrocycle 3 with aromatic di- and tetra- carboxylate anions in water were done using absorption, emission, ¹ H NMR and NOESY spectroscopic titrations. The NDI incorporated macrocycle 3 showed high binding affinities towards linear aromatic tetracarboxylate anions owing to the size and charge complementarity of the host-guest complex. Macrocycle 3 binds tetracarboxylate anion much better than dicarboxylate anions. Furthermore, the macrocycle 3 is solvated differently in acetonitrile and in water or dimethyl sulfoxide, which induces changes in conformation and photophysical properties. Such electron-deficient optically active macrocycles are useful for developing useful sensor materials.

Recent progress in the usage of tetrabromo-substituted naphthalenetetracarboxylic dianhydride as a building block to construct organic semiconductors and their applications

The recent synthetic strategies and significant applications of TBNDA and their derivatives as promising building blocks to construct π-expanded semiconductors have been carefully summarized in this review.

A 2-(benzo[d]thiazol-2-yl)phenol based on conjugated polymer: Highly selective colorimetric fluorescent chemosensor for F-depending on Si–O bond cleavage reaction

Design and synthesis of highly selective fluorine ion probes become particularly important owing to the specific role of fluorine ion in chemical and biomedical progresses. As a new-type of fluorescent material, conjugated polymers with unique photometric properties have been widely researched by scientists in the field of the fluorescence sensors. In this study, the polymer PBTPV-OSi containing benzothiazole moiety is synthesized via palladium-catalyzed Heck coupling reaction. This polymer not only exhibits good solubility in organic solvents but also shows high selectivity for fluorine ion detection in comparison to other anions. Upon addition of F− to PBTPV-OSi solution, Si–O cleavage of PBTPV-OSi leads to the fluorescence quenching of the polymer in tetrahydrofuran dramatically, and the detection limit is 8 × 10−6 mol/L. Moreover, besides detecting fluorine ion from organic phase, the probe can also effectively detect potassium fluoride from inorganic phase. More importantly, a naked-eye detectable chromogenic and fluorogenic dual response to fluorine ion (F−) can be visibly noted and the detection process of fluorine ion is relatively fast.

Investigation of cation binding and sensing by new crown ether core substituted naphthalene diimide systems

Different modes of cation binding lead to very different optical readouts from two structurally similar sensors.

Rise of Conjugated Poly-ynes and Poly(Metalla-ynes): From Design Through Synthesis to Structure-Property Relationships and Applications

Conjugated poly-ynes and poly(metalla-ynes) constitute an important class of new materials with potential application in various domains of science. The key factors responsible for the diverse usage of these materials is their intriguing and tunable chemical and photophysical properties. This review highlights fascinating advances made in the field of conjugated organic poly-ynes and poly(metalla-ynes) incorporating group 4-11 metals. This includes several important aspects of conjugated poly-ynes viz. synthetic protocols, bonding, electronic structure, nature of luminescence, structure-property relationships, diverse applications, and concluding remarks. Furthermore, we delineated the future directions and challenges in this particular area of research.

Dual-Analyte Fluorescent Sensor Based on [5]Helicene Derivative with Super Large Stokes Shift for the Selective Determinations of Cu2+ or Zn2+ in Buffer Solutions and Its Application in a Living Cell

A new fluorescent sensor, M201-DPA, based on [5]helicene derivative was utilized as dual-analyte sensor for determination of Cu²⁺ or Zn²⁺ in different media and different emission wavelengths. The sensor could provide selective and bifunctional determination of Cu²⁺ in HEPES buffer containing Triton-X100 and Zn²⁺ in Tris buffer/methanol without interference from each other and other ions. In HEPES buffer, M201-DPA demonstrated the selective ON-OFF fluorescence quenching at 524 nm toward Cu²⁺. On the other hand, in Tris buffer/methanol, M201-DPA showed the selective OFF-ON fluorescence enhancement upon the addition of Zn²⁺, which was specified by the hypsochromic shift at 448 nm. Additionally, M201-DPA showed extremely large Stokes shifts up to ∼150 nm. By controlling the concentration of Zn²⁺ and Cu²⁺ in a living cell, the imaging of a HepG2 cellular system was performed, in which the fluorescence of M201-DPA in the blue channel was decreased upon addition of Cu²⁺ and was enhanced in UV channel upon addition of Zn²⁺. The detection limits of M201-DPA for Cu²⁺ and Zn²⁺ in buffer solutions were 5.6 and 3.8 ppb, respectively. Importantly, the Cu²⁺ and Zn²⁺ detection limits of the developed sensors were significantly lower than permitted Cu²⁺ and Zn²⁺ concentrations in drinking water as established by the U.S. EPA and WHO.

A near-infrared fluorescent probe for selective and quantitative detection of fluoride ions based on Si-Rhodamine

A highly selective fluorescent probe (SiROPS) based on Si-rhodamine (SiR) towards F^- was investigated. SiROPS can realize the NIR detection of F^- because of the long fluorescent wavelength (λ_ex = 650 nm, λ_em = 669 nm). The near-IR optical and the ratiometric fluorescence type signaling were realized by employing fluoride-selective cleavage of the latent thiophosphinated probe in mixed aqueous media. The cleavage of F^- to the ortho positions of dimethylphosphinothionyl group in the meso aryl involves the suppression of internal rotation upon phosphorylation of a reactive phenolate and the activating rotation of o-OH, which resulting in a large fluorescence "Turn-Off" response. The detection limit of the probe to F^- was 48 nM in the dynamic range of 0.5 μM-20 μM. In addition, the proposed probe has been used to detect F^- in water samples and toothpaste samples with satisfying results.

Colorimetric and fluorescent sensing of a new FRET system via [5]helicene and rhodamine 6G for Hg2+ detection

A “visually colorimetric” and fluorometric sensor based on [5]helicene connected to rhodamine 6G via a hydrazide moiety was designed and prepared for the highly sensitive and selective detection of Hg²⁺.

Fluoroalkyl-modified naphthodithiophene diimides

Two kinds of fluoroalkyl-modified naphthodithiophene diimides (NDTI) were designed and synthesized. α-Modified NDTI could form favorable slipped one-dimensional (1D) stacking and N-modified NDTI shows a torsion cofacial stacking. Single-crystal transistors confirm that both fluoroalkyl-modified NDTI possess good electron transport ability with electron mobilities of 0.065 cm² V^-1 s^-1 and 1.59 cm² V^-1 s^-1, respectively.

An aggregation-induced emission (AIE) active probe for multiple targets: a fluorescent sensor for Zn(2+) and Al(3+) & a colorimetric sensor for Cu(2+) and F(-)

A rationally designed probe L, which consists of both cation and anion binding sites, is capable of displaying interesting aggregation induced emission (AIE) properties. L not only can sense Al(3+) and Zn(2+) through selective turn-on fluorescence responses in 9 : 1 methanol-HEPES buffer (5 mM, pH 7.3; 9 : 1, v/v) medium due to metal ion triggered AIE activity, but also can distinguish them through individual emission signals. L can also detect Cu(2+) in mixed buffer medium and F(-) in acetonitrile through sharp colorimetric responses. All the sensing processes are conspicuous through the naked eye. A theoretical study strongly backed the proposed sensing mechanisms.

Tuning the reaction rates of fluoride probes for detection in aqueous solution

Tuning the reaction rates of fluoride probes for detection in aqueous solution by varying the pendent groups of probe molecules.

Poly(norbornyl-NDIs) as a potential cathode-active material in rechargeable charge storage devices

Two pendant-type naphthalene diimide (NDI) polymers bearing a polynorbornene backbone were prepared and their electrochemical properties explored.

A switchable electrochemical redox ratiometric substrate based on ferrocene for highly selective and sensitive fluoride detection

A ferrocene based electrochemical redox substrate for highly selective and sensitive fluoride detection in non-transparent solutions.

Novel indole based dual responsive "turn-on" chemosensor for fluoride ion detection

An efficient new dual channel chemosensor 2,3-bis((E)-(1H-indole-3-yl)methyleneamino)maleonitrile (DN) which exhibits selective sensing of F(-) ions in DMSO, was synthesized by a facile one step condensation reaction of indole-3-carboxaldehyde with diaminomaleonitrile. The probe DN was characterized by elemental analysis, (1)H, (13)C-NMR, ESI-MS and IR spectral techniques. Upon addition of F(-), DN induces remarkable changes in both absorption and fluorescence spectra on the basis of charge transfer mechanism. The receptor DN serves for highly selective, sensitive detection of F(-) without the interference of other relevant anions. The Job's plot analysis indicates the binding stoichiometry to be 1:1 (host/guest).

A novel pyrazoline-based fluorescent probe for detecting fluoride ion in water and its application on real samples

We have designed and synthesized a new fluorescent probe, pyrazoline-based probe 1, to detect fluoride ion with high selectivity and sensitivity in aqueous media.

A study on fluoride detection and assembly of hydroxyaromatic aldoximes caused by tetrabutylammonium fluoride

Different assemblies formed by the interactions of tetrabutylammonium fluoride with hydroxy-aromatic oximes show characteristic optical properties.

A highly selective colorimetric Cys sensor based on core-substituted naphthalene diimides

This study presents the core-substituted naphthalenediimide based probe 1 for the selective detection of cysteine via photoinduced electron transfer (PET) effect.

Synthesis of Novel Fluorescent Sensors Based on Naphthalimide Fluorophores for the Highly Selective Hg2+-Sensing

With an aim to develop the new sensors for optical detection of Hg2+ions, two novel fluorometric sensors were designed and successfully prepared using 2-(3-(2-aminoethylsulfanyl)propylsulfanyl)ethanamine and one or twoN-methylnaphthalimide moieties (1and2). Sensor1was obtained viaN-alkylation,N-imidation and a one-pot nucleophilic aromatic substitution, andN-formylation of the amine, while sensor2was prepared viaN-alkylation,N-imidation, and nucleophilic aromatic substitution. The characterization, including1H NMR,13C NMR, and mass spectrometry, was then performed for1and2. The Hg2+-binding behaviors of the sensors were investigated in terms of sensitivity and selectivity by fluorescence spectroscopy. Sensor1especially provided the reversible and highly Hg2+-selective ON-OFF fluorescence behavior by discriminating various interfering ions such as Pb2+, Co2+, Cd2+, Mn2+, Fe2+, K+, Na+, and in particular Cu2+and Ag+with a detection limit of 22 ppb toward Hg2+ions.

Chromogenic and fluorescent 'turn-on' chemodosimeter for fluoride based on a F(-)-triggered cascade reaction

We developed a new chromogenic and fluorescent 'turn-on' chemodosimeter 1 based on a F(-)-triggered cascade reaction. This system displayed significant changes in UV/vis absorption and fluorescence emission intensities selectively for F(-) over other anions in a mixture of CH3CN/H2O(95 : 5, v/v) and in acetonitrile.