Impact of doping with organic dopants and mixed doping with alkali metals and organic dopants on the absorption, electronic, optoelectronic, thermodynamic and nonlinear optical properties of dibenzo[b,def]chrysene in gaseous media: DFT and TD-DFT studies

CONTEXT

In this study, we evaluate the geometrical, absorption, optoelectronic, electronic, nonlinear optical (NLO) and thermodynamic properties of dibenzo[b,def]chrysene molecule derivatives by means of DFT and TD-DFT simulations. In view of the aim of producing new high-performance materials for non-linear optics (NLO) by doping test, two types of doping were used. We obtained six derivatives by doping with organic dopants (Nitro, amide and ticyanoethenyl) and mixed alkali metal (potassium) and organic dopants. Doping with organic dopants produced molecules A, B and C, respectively when substituting one hydrogen with nitro (NO2), amide (CONH2) and tricyanoethenyl (C5N3) groups, while mixed doping involved considering A, B and C and then substituting two hydrogens with two potassiums to obtain compounds D, E and F respectively. The negative values of the various interaction energies calculated for all the doped molecules show that they are all stable, but also that molecules C and F are the most stable in the case of both dopings. The gap energies calculated at the B3LYP level of theory are all below 3 eV, which means that all the molecules obtained are semiconductors. Better still, compounds C and F, with gap energies of 1.852 eV and 1.204 eV, respectively, corresponding to decreases of 35.67% and 58.18% in gap energy compared with the pristine molecule, are more reactive than the other doped molecules. Mixed doping is therefore a highly effective way of narrowing the energy gap and boosting the semiconducting character and reactivity of organic materials. Optoelectronic properties have also been improved, with refractive index values higher than those of the reference material, glass. This shows that our compounds could be used under very high electric field conditions of the order of 4.164 × 109 V.m-1 for C and 7.410 × 109 V.m-1 for F the highest values at the B3LYP level of theory. The maximum first-order hyperpolarizability values for both types of doping are obtained at the CAM-B3LYP level of theory by C:β mol = 92.088 × 10-30esu and by F:β mol = 129.449 × 10-30esu, and second-order values are also given by these same compounds. These values are higher than the reference value, which is urea, making our compounds potential candidates for high-performance NLO applications. In dynamic mode and at a frequency of 1064 nm, at the CAM-B3LYP level of theory, the highest dynamic hyperpolarizability coefficients were obtained by C and F. Hyper-Rayleigh scattering β HRS , coefficients of the electro-optical Pockel effect (EOPE), EFISHG, third-order NLO-response degree four-wave mixingγ DFWM , quadratic nonlinear refractive index n2 were also calculated. The maximum values of n2 are obtained by C (6.13 × 10-20 m2/W) and F (6.60 × 10-20 m2/W), these values are 2.24 times higher than that of fused silica which is the reference for degenerate four-wave mixing so our molecules could also have applications in optoelectronics as wavelength converters, optical pulse modulators and optical switches.

METHODS

Using the DFT method, we were able to determine the optimized and stable electronic structures of doped dibenzo[b,def]chrysene derivatives in the gas phase. We limited ourselves to using the proven B3LYP and CAMB3LYP levels of theory for calculating electronic properties, and non-linear optics with the 6-311G +  + (d,p) basis set, which is a large basis set frequently used for these types of compound. Gaussian 09 software was used to run our calculations, and Gauss View 6.0.16 was used to visualize the output files. TD-DFT was also used to determine absorption properties at the B3LYP level of theory, using the same basis set.

A reaction-based carbazole-dicyanovinyl conjugated colorimetric and ratiometric fluorescent probe for selective detection of cyanide ions

In the present work, 4-(9'-hexylcarbazol-3'-yl)benzylidenemalononitrile 5 (probe L) was tested as a colorimetric and ratiometric fluorescent probe in dimethyl sulfoxide (DMSO) medium towards anions, cations and neutral molecules. The sensing properties of probe L were investigated by using UV-Vis absorption and fluorescence spectroscopy techniques. Probe L showed selectivity and sensitivity towards cyanide ions (CN-) in the presence of analytes used. Upon the addition of CN-, intramolecular charge transfer (ICT) band at 425 nm in UV spectrum disappeared. In addition, ICT emission intensity at 593 nm decreased and ligand-centred (LC) emission intensity at 480 nm increased. These findings indicate that nucleophilic conjugate addition of CN- to the dicyanovinyl group of probe L successfully occurs, hence forming a new adduct between probe L and CN-. In this adduct, π-conjugation was partially blocked, and the ICT transfer was hindered. Adduct formation was proved by Job's plot, 1H NMR and FT-IR analysis. Probe L showed very low limit of detection (LOD) value of 1.467 nM towards CN-. Probe L was also applied to the CN- detection in real-world water samples by the spike and recovery method. The maximum relative standard deviation (RSD) value was 4.24, indicating this method works successfully. Therefore, probe L could find a potential use in detection of CN- in liquid media.

Synthesis, Spectral, Redox, and Sensing Studies of β-Dicyanovinyl-Appended Corroles and Their Metal Complexes

A new family of β-dicyanovinyl (DCV)-appended corroles represented as MTPC(MN) (where M = 3H, Cu, Ag, and Co(PPh₃) and MN = malononitrile and TPC = 5,10,15-triphenylcorrole) were synthesized starting from the free base mono β-formyl corrole, H₃TPC(CHO), and characterized along with their respective MTPC(CHO) and MTPC complexes as to their spectroscopic and electrochemical properties in nonaqueous media. Comparisons between the two series of corroles demonstrate a pronounced substituent effect of the β-DCV group on the physicochemical properties making the MTPC(MN) derivatives substantially easier to reduce and more difficult to oxidize than the formyl or unsubstituted corroles. In addition, the colorimetric and spectral detection of 11 different anions (X) in the form of tetrabutylammonium salts (TBAX, X = PF₆^-, OAc^-, H₂PO₄^-, CN^-, HSO₄^-, NO₃^-, ClO₄^-, F^-, Cl^-, Br^-, and I^-) were also investigated in nonaqueous media. Of the investigated anions, only CN^- was found to induce changes in the UV-vis and ¹H NMR spectra of the β-DCV metallocorroles. This data revealed that CuTPC(MN) and AgTPC(MN) act as chemodosimeters for selective cyanide ion detection via a nucleophilic attack at the vinylic carbon of the DCV substituent, while (PPh₃)CoTPC(MN) acts as a chemosensor for cyanide ion sensing via axial coordination to the cobalt metal center. A low-limit detection of cyanide ions was observed at 1.69 ppm for CuTPC(MN) and 1.17 ppm for AgTPC(MN) in toluene.

Curcumin Is an Iconic Ligand for Detecting Environmental Pollutants

The rapid increase in industrial revolution and the consequent environmental contamination demands continuous monitoring and sensitive detection of the pollutants. Nanomaterial-based sensing system has proved to be proficient in sensing environmental pollutants. The development of novel ligands for enhancing the sensing efficiency of nanomaterials has always been a challenge. However, the amendment of nanostructure with molecular ligand increases the sensitivity, selectivity, and analytical performance of the resulting novel sensing platform. Organic ligands are capable of increasing the adsorption efficacy, optical properties, and electrochemical properties of nanomaterials by reducing or splitting of band gap. Curcumin (diferuloylmethane) is a natural organic ligand that exhibits inherent fluorescence and electrocatalytic property. Due to keto-enol tautomerism, it is capable of giving sensitive signals such as fluorescence, luminescence, ultraviolet absorption shifts, and electrochemical data. Curcumin probes were also reported to give enhanced meterological performances, such as low detection limit, repeatability, reproducibility, high selectivity, and high storage stability when used with nanosystem. Therefore, research on curcumin-modified nanomaterials in the detection of environmental pollution needs a special focus for prototype and product development to enable practical use. Hence, this article reviews the role of curcumin as a natural fluorophore in optical and electrochemical sensing of environmentally significant pollutants. This review clearly shows that curcumin is an ideal candidate for developing and validating nanomaterials-based sensors for the detection of environmental pollutants such as arsenic, lead, mercury, boron, cyanide, fluoride, nitrophenol, trinitrotoluene, and picric acid and toxic gases such as ammonia and hydrogen chloride. This review will afford references for future studies and enable researchers to translate the lab concepts into industrial products.

A CH-Controlled Colorimetric Probe Based on Anthracene Carboximide for Near-Infrared Cyanide Detection

A chemical sensor that can induce near-infrared red-shifted response represents a promising strategy for the design and development of anion probes. In this work, novel CH-controlled colorimetric probe 3 based on anthracene carboximide was developed for near-infrared detection of cyanide. Probe 3 consisted of CHCN binding site to anthracene carboximide fluorophore, and showed a significant visual change from yellow-green (535 nm) to deep violet (825 nm) with a larger redshift (≈ 290 nm) and fluorescence quenching at 480 nm and 520 nm upon interacting with cyanide. Job curves determined 1:1 binding stoichiometry of probe 3 with cyanide. Additonally, probe 3 detected cyanide ion conveniently in aqueous solution and could be reused after trifluoroacetic acid treatment. Colorimetric test paper was used to detect cyanide in aqueous solutions. The C-H deprotonation sensing mechanism was confirmed by ¹H NMR titration. The near-infrared detection of cyanide by CH-controlled probes was founded for the first time.

A sensitive and selective BINOL based ratiometric fluorescence sensor for the detection of cyanide ions

A highly selective, novel BINOL based sensor BBCN has been developed for the fluorescent ratiometric detection of cyanide ions (CN⁻). The optical study revealed that BBCN exhibited unique spectral changes only with cyanide ions in the presence of other competing ions. Besides, an apparent fluorescent colour change from green to blue was observed. A clear linear relationship was observed between the fluorescence ratiometric ratio of BBCN and the concentration of CN⁻ with a reasonably low detection limit (LOD) of 189 nM (507 ppb). The optical response was due to the nucleophilic addition of CN⁻ to the dicyanovinyl group of the sensor, which compromises the probe's intramolecular charge transfer. This mechanism was well confirmed by Job's plot, ¹H-NMR and ESI-MS studies. BBCN showed immediate spectral response towards (1 second) CN⁻ and detection could be realized in a broad pH window. Furthermore, the practical utility of BBCN was studied by test paper-based analysis and the detection of CN⁻ in various water resources.

A highly selective, novel BINOL based sensor BBCN has been developed for the fluorescent ratiometric detection of cyanide ions (CN⁻).

Rational Design of an ICT-Based Chemodosimeter with Aggregation-Induced Emission for Colorimetric and Ratiometric Fluorescent Detection of Cyanide in a Wide pH Range

An alkoxy-substituted 1,3-indanedione-based chemodosimeter 1 with an aggregation-induced emission (AIE) characteristic was rationally designed and synthesized for the ultrasensitive and selective sensing of cyanide in a wide pH range of 3.0-12.0. The nucleophilic addition of cyanide to the β-conjugated carbon of the 1,3-indanedione group obstructs intramolecular charge transfer (ICT) and causes a significant change in the absorption and fluorescence spectra, enabling colorimetric and ratiometric fluorescent detection of cyanide in a 90% aqueous solution. The cyanide-sensing mechanism is supported by single-crystal X-ray diffraction analysis, time-dependent density functional theory (TD-DFT) calculations, and 1H NMR titration experiments. Sensor 1 exhibits strong yellow fluorescence in the solid state due to the AIE effect, and the paper probes containing 1 can be conveniently used to sense cyanide by the naked eye. Furthermore, chemodosimeter 1 was successfully used for sensing cyanide in real environmental water samples.

Highly sensitive turn-off fluorescent detection of cyanide in aqueous medium using dicyanovinyl-substituted phenanthridine fluorophore

Herein, the turn-off fluorescence sensor of 2-((4'-(7,8,13,14-tetrahydrodibenzo[a,i]phenanthridin-5-yl)-[1,1'-biphenyl]-4-yl)methylene)malanonitrile (7) was developed for the recognition of CN- ions and studied using different spectroscopic techniques. The selective recognition of CN- ions by 7 was investigated via UV-vis spectroscopy and fluorescence studies in acetonitrile solvent, which exhibited an obvious color change from orange to colorless under 365 UV light. The sensor compound 7 possesses a high binding constant (K a) for CN- ions in the order of 5.22 × 106 M-1. The results from the interference studies revealed that probe 7 shows high sensing selectivity and sensitivity for CN- ions over other competitive anions. Probe 7 interacts with cyanide to form a 1 : 1 adduct, and this mechanism was further verified by 1H NMR titration, Job's plot analyses and DFT studies. The sensor probe 7 exhibits advantages such as low limit of detection (LOD) of 39.3 nM, fast response and sensing in a wide pH range of 3 to 11. The practical application of 7 was successfully demonstrated for the determination of CN- ions in test paper strips and various water samples.

A new phenothiazine-based selective visual and fluorescent sensor for cyanide

A new donor-π-acceptor derived from phenothiazine, namely 2-(2-((10-hexyl-10H-phenothiazin-3-yl)methylene)-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile (PTZON) was synthesized and fully characterized, and its potential as a fluorescent sensor for cyanide anion was investigated. The PTZON showed a visible absorption band at 564 nm corresponds to an intramolecular charge transfer (ICT) and an emission band at 589 nm in CH₃CN/H₂O. The results of cyanide anion titration revealed ratiometric changes in both absorption and fluorescence spectra as a result of the nucleophilic addition of cyanide anion via Michael addition. The optical studies, FT-IR spectra, NMR, high-resolution mass, and DFT calculations confirmed the sensing mechanism. The selectivity of PTZON as a cyanide anion fluorescent sensor was proved in mixed solvent solutions, and the sensitivity was as low as 0.011 µM, which is far lower than the value allowed by the United States Environmental Protection Agency for drinking water (1.9 µM). Also, the detection limit of PTZON was assessed to be 3.39 μM by the spectrophotometric method. The binding stoichiometry between PTZON and cyanide anion was found to be 1:1 as evidenced by mass spectra. TLC silica-coated plates test strips demonstrated the fluorescent detection of cyanide anion.

Colorimetric N-butyl-3,6-diamidecarbazole-based chemosensors for detection of fluoride and cyanide anions

Colorimetric sensors from N-butyl-3,6-disubstituted carbazole derivatives containing nitroazobenzene (1) and nitrobenzene (2) were designed, synthesized and compared for their anion sensing ability. Computational simulations were undertaken to determine the optimum geometry of 1. Anion sensing studies revealed that selectivity in anion detection depended on the polarity of solvent, acidity of binding unit and basicity of the anion. The ability to sense via naked eye observations using the strong basic anions (F^- and CN^-) for both sensors arises from a deprotonation process at the binding sites attributed to the intramolecular charge transfer transition at the sensory unit. The discrimination of F^- from CN^- has been achieved by the optimization of solvent polarity. Sensor 1 offers a promising property over sensor 2 with a lower detection limit, a few of anion interference and higher stability.

Anion Sensing by Novel Triarylboranes Containing Boraanthracene: DFT Functional Assessment, Selective Interactions, and Mechanism Demonstration

Analytical methods often involve expensive instrumentation and tedious sample pretreatment for an analyte detection. Being toxic and detrimental to human health, sensing of cyanide (CN-), fluoride (F-), chloride (Cl-), bromide (Br-), nitrate (NO3 -), acetate (CH3COO-), and bisulfate (HSO4 -) is performed by a boron-based molecular receptor, N,N,N,3,5-pentamethyl-4-{2-thia-9-boratricyclo[8.4.0.03,8]tetradeca-1(10),3(8),4,6,11,13-hexaen-9-yl}anili-nium (1), and the three newly designed receptors from it. Thermodynamics, electronic structure, and photophysical properties are computed by employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to explore selective sensing of these anions and its mechanism. Free-energy changes (ΔG) and binding energies (ΔE) suggest that among these anions, only binding of CN- and F- is thermodynamically feasible with a very strong binding affinity with the receptors. Boron atoms containing positive natural charges act as the electrophilic centers to bind the anions involving a 2p-2p orbital overlap resulting in charge transfer. In the receptor-analyte complexes with CN- and F-, fluorescence is quenched due to the intramolecular charge transfer transitions (π-π* transitions in the case of the receptors lead to fluorescence), internal conversion, and associated configurational changes. Among the six tested functionals, CAM-B3LYP/6-31G(d) is found to be the most accurate one. The designed receptors are better fluorescent probes for F- and CN-, demonstrating their importance for the practical utility.

Tuning the Photophysical and Electroluminescence Properties in Asymmetrically Tetrasubstituted Bipolar Carbazoles by Functional Group Disposition

Carbazoles decorated with both donor and acceptor fragments offer a classical way to optimize bipolar functional properties. In this work, a series of carbazoles featuring triphenylamine donors and cyano acceptors are synthesized and their structure-property relationship is studied. The effects of connectivity and the chromophore number density on photophysical and electroluminescence properties are investigated. The position of the triphenylamine donor on the 3,6-dicyanocarbazole nucleus significantly affected the photophysical and electroluminescence properties. The dye possessing triphenylamine on C2 and C7 displayed a red shift in absorption when compared with the structural analogue with triphenylamine tethered to C1 and C8. The emission wavelength of the dyes are tunable from blue to green, by altering the position of triphenylamine and cyano substituents. All of the dyes exhibited positive solvatochromism in emission, attributable to the photoinduced intramolecular charge transfer from the triphenylamine donor to the cyano acceptor. However, the extent of charge transfer and hybridization of local and charge-transfer-excited states is highly dependent on the position of triphenylamine and cyano groups on the carbazole nucleus. Dyes containing cyano substituents at C2 and C7 showed a prolonged excited state lifetime, broad emission, and large Stokes shifts, indicating the presence of a higher charge transfer component in the excited state. The dyes displayed exceptional thermal stability with the onset decomposition temperature (10% weight loss) > 350 °C. Electrochemical measurements revealed low oxidation potential for dyes containing triphenylamine at C3 and/or C6. Addition of a cyano acceptor on carbazole led to the stabilization of lowest unoccupied molecular orbital. Furthermore, the materials were tested as emitting dopants in solution-processable multilayer organic light emitting diodes and found to display deep-blue/sky-blue electroluminescence with external quantum efficiency as high as 6.5% for a deep-blue emitter (CIE y ∼ 0.06).

A theoretical study on anion sensing mechanism of multi-phosphonium triarylboranes: intramolecular charge transfer and configurational changes

The binding selectivity and recognition mechanism of a series of mono-, di- and triphosphonium substituted triarylboranes: (4-(dimesitylboryl)-3,5-dimethylphenyl)phosphonium ([Mes₂BAr^P]⁺, 1), 1,1'-mesitylboranediylbis(3,5-dimethylphenyl)phosphonium ([MesBAr^P₂]²⁺, 2) and 1,1',1''-boranetriyltris(3,5-dimethylphenyl)phosphonium ([BAr^P₃]³⁺, 3) where Ar^P = 4-(H₃P)-2,6-Me₂-C₆H₂, for various anions has been investigated by employing density functional theory (DFT) and time dependent-density functional theory (TD-DFT) methods. Natural population analysis indicates the electrophilic nature of the boron centers in 1-3 for the nucleophilic addition of anions. The calculated free energy changes (ΔG) reveal that out of CN^-, F^-, Cl^-, Br^-, NO₃^-, CH₃COO^- and HSO₄^- only the binding of CN^- and F^- with 1, 2 and 3 is thermodynamically feasible. In addition, the calculated binding energies reflect that CN^- shows lesser binding affinity than F^- with 1, 2 and 3. Frontier molecular orbital (FMO) analysis reveals that the first excited states (S₁) of 1-3 are the local excited states with a π → π* transition, whereas the third excited state (S₃), fifth excited state (S₅), fourth excited state (S₄) and fourth excited states (S₄) of [Mes₂BAr^P]⁺F (1F, the fluoro form of 1), [MesBAr^P₂]²⁺F (2F, the fluoro form of 2), [Mes₂BAr^P]⁺CN (1CN, the cyano form of 1) and [MesBAr^P₂]²⁺CN (2CN, the cyano form of 2), respectively, are charge separation states found to be responsible for the intramolecular charge transfer (ICT) process. The partial configuration changes and ICT induce fluorescence quenching in 1F, 2F, 1CN and 2CN synergistically after an internal conversion (IC) from their respective S₃, S₅, S₄ and S₄ to S₁.

Nanomolar-level selective dual channel sensing of Cu2+and CN−from an aqueous medium by an opto-electronic chemoreceptor

A novel chromogenic and fluorogenic chemoreceptor exhibiting a proclivity towards Cu²⁺and CN⁻, with applications in bioimaging and molecular electronics, was developed.

Studies on a multifunctional chromo-fluorogenic sensor for dual channel recognition of Zn2+ and CN− ions in aqueous media: mimicking multiple molecular logic gates and memory devices

A new effectual naphthalene-based azomethine receptor has been systematically designed and synthesized as a selective colorimetric and fluorescent chemosensor for dual channel detection of cations and anions in aqueous environments.

Selective Complexation of Cyanide and Fluoride Ions with Ammonium Boranes: A Theoretical Study on Sensing Mechanism Involving Intramolecular Charge Transfer and Configurational Changes

The anion binding selectivity and the recognition mechanism of two isomeric boranes, namely, 4-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline ([p-(Mes₂B)C₆H₄(NMe₃)]⁺, 1, where "Mes" represents mesitylene and "Me" represents methyl) and 2-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline ([o-(Mes₂B)C₆H₄(NMe₃)]⁺, 2) has been investigated using density functional theory (DFT) and time dependent-density functional theory (TD-DFT) methods. Natural population analysis indicates that the central boron atoms in 1 and 2 are the most active centers for nucleophilic addition of anions. The negative magnitude of free energy changes (ΔG) reveals that out of CN^-, F^-, Cl^-, Br^-, NO₃^-, and HSO₄^- only the binding of CN^- and F^- with 1 and 2 is thermodynamically feasible and spontaneous. In addition, the calculated binding energies reveal that the CN^- is showing lesser binding affinity than F^- both with 1 and 2, while other ions, viz. NO₃^-, HSO₄^-, Br^-, and Cl^-, either do not bind at all or show very insignificant binding energy. The first excited states (S₁) of 1 and 2 are shown to be the local excited states with π → σ* transition by frontier molecular orbital analysis, whereas fourth excited states (S₄) of 4-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline cyanide ([p-(Mes₂B)C₆H₄(NMe₃)] CN, 1CN, the cyano form of 1) and 4-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline fluoride ([p-(Mes₂B)C₆H₄(NMe₃)] F, 1F, the fluoro form of 1) and fifth excited state (S₅) of 2-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline fluoride ([o-(Mes₂B)C₆H₄(NMe₃)] F, 2F, the fluoro form of 2) are charge separation states that are found to be responsible for the intramolecular charge transfer (ICT) process. The synergistic effect of ICT and partial configuration changes induce fluorescence quenching in 1CN, 1F, and 2F after a significant internal conversion (IC) from S₄ and S₅ to S_1.

Carbazole- and/or triphenylamine-based D–π–D multiarylamino dyes: synthesis, characterization and photophysical properties

One-photon and two-photon fluorescence quenching by benzoyl peroxide of D–π–D multiarylamino dyes was investigated.

Promising ESIPT-based fluorescence sensor for Cu2+ and CN− ions: investigation towards logic gate behaviour, anticancer activities and bioimaging application

An excited state intramolecular proton transfer (ESIPT) process-based novel chromogenic and fluorogenic probe (2) was synthesized with the aim of sequential in situ detection of Cu²⁺ and CN⁻ ions under aqueous and biological conditions.

Selective and sensitive colorimetric sensor for CN− in the absence and presence of metal ions (Cu2+/Ni2+): mimicking logic gate behaviour

Enone based anion sensors have significance due to their colorimetric reaction upon deprotonation and variable occurrence in the conjugated moiety.

A pyrylium–coumarin dyad as a colorimetric receptor for ratiometric detection of cyanide anions by two absorption bands in the visible region

A pyrylium–coumarin dyad behaves as a colorimetric receptor for ratiometric detection of cyanide anions in aqueous media by two absorption bands in the visible wavelength region.

A novel phenylacetylene-indolium fluorophore for detection of cyanide by the naked eye

The compound 2 mixed α-cyclodextrin exhibits the highest CN⁻ recognition sensitivity in aqueous media with the detection limit of 1.3 μM. Test strips based on compound 2 can act as a convenient and efficient CN⁻ test kit.

Porphyrin chemodosimeters: synthesis, electrochemical redox properties and selective ‘naked-eye’ detection of cyanide ions

β-Dicyanovinyl substituted porphyrins have been synthesized and utilized as chemodosimeters for ratiometric and colorimetric sensing of cyanide ions in CH₃CN and H₂O/CH₃CN mixture.

Effects of substituents on fluorometric detection of cyanide anions by indolium–coumarin dyads

Fluorometric detection of cyanide anions was carried out with indolium–coumarin dyads in aqueous media. Substituents on the dyads strongly affect the selectivity, sensitivity, and response to cyanide anions.

Fe-catalyzed cycloaddition of indoles and o-phthalaldehyde for the synthesis of benzo[b]carbazoles with TMSCl- or acid-responsive properties

The indolyl benzo[b]carbazoles achieved by iron catalysis via sequential carbon–carbon bond-forming reaction could be used as fluorescent sensors for TMSCl and acids.