A highly selective turn-on colorimetric and luminescence sensor based on a triphenylamine-appended ruthenium(Ⅱ) dye for detecting mercury ion

A dual colorimetric and luminescent sensor based on a heteroleptic ruthenium dye [Ru（Hipdpa）（Hdcb- py）（NCS）2]^-.0.5H^＋ 0.5[N（C4H9）4]＋ Ru（Hipdpa） {where Hdcbpy = monodeprotonted-4,4＇-dicarboxy-2,2＇- bipyridine and Hipdpa = 4-（1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl）-N,N-diphenylaniline} for selective detection of Hg2. is presented. The results of spectrophotometric titrations revealed an evident luminescence intensity enhancement （I/Io = 11 ） and a considerable blue shift in visible absorption and luminescence maxima with the addition of rig2.. The sensitive response of the optical sensor on Hg^2＋ was attributed to the binding of the electron-deficient Hg^2＋ to the electron-rich sulfur atom of the thiocyanate （NCS） ligand in the Ru（Hipdpa）, which led to an increase in the energy gap between the highest occupied molecular orbital （HOMO） and the lowest unoccupied molecular orbital （LUMO）. Accordingly, the blue shift in the absorption spectrum of Ru（Hipdpa） due to the binding of Hg2. was obtained. Ru（Hipdpa） was found to have decreased Hg2~ detection limit and improved linear region as compared to di（tetrabutylammonium） cis-bis（isothiocyanato）bis（2,2＇-bipyridine-4-carboxylic acid-4＇- carboxylate）ruthenium（ll） N719. Moreover, a dramatic color change from pink to yellow was observed, which allowed simple monitoring of Hg^2＋ by either naked eyes or a simple colorimetric reader. Therefore, the proposed sensor can provide potential applications for Hg2＊ detection.

A Phenyl Sulfide Functionalized Luminescent Sensors for Efficient Fe3+ and Cr2O72- Ions Detection

A new complex, {[Cd(BIDPT)(NBA)]}n(1), was synthesized from the selfassembly of BIDPT(BIDPT = 4,4'-bis(imidazol-l-yl)diphenyl thioether) and H2NBA(H2 NBA = 4,4'-azanediyldibenzoic acid) ligands with Cd(Ⅱ). 1 was characterized by infrared spectroscopy, powder X-ray diffraction, elemental analysis, and thermogravimetry measurement. 1 crystallizes in monoclinic system, space group P21/c with a = 8.8204(1), b = 29.835(3), c = 10.3813(1) A, β = 96.180(2)°, V = 2730.7(5) A^3, Z = 4, C32H22CdN5O4S, Mr = 685.01, Dc = 1.666 g/cm^3, μ = 0.926 mm^-1, R = 0.0548 and wR = 0.1528. 1 features a parallel structure with 3-connected hcb network and the adjacent 2 D networks are stacked together via C–H···π interaction to form a 3 D network. Its application in detecting metal cations and inorganic anions was explored. 1 exhibits excellent photoluminescence sensing for Fe^3+ and Cr2O7^2- ions. And the mechanism of quenching is also studied.

2D Cd-MOF and its mixed-matrix membranes for luminescence sensing antibiotics in various aqueous systems and visible fingerprint identifying

The abuse of antibiotics has brought great harm to the human living environment and health,so it is extremely significant to develop an efficient and simple method to detect trace antibiotic residues in various wastewaters.Herein,a new two-dimensional(2D)Cd-based metal−organic framework(Cd-MOF,namely LCU-111)and its mixed matrix membranes(MMMs)is sifted as luminescence sensors for efficient monitoring antibiotic nitrofurazone(NFZ)in various aqueous systems and applied as visible fingerprint identifying.The LCU-111 has good selectivity,sensibility,reproducibility and anti-interference for luminescent quenching NFZ with low detection limits(LODs)of 0.4567,0.3649 and 0.8071 ppm in aqueous solution,HEPES biological buffer,and real urban Tuhai River water,respectively.Interestingly,the luminescent test papers and MMMs allow the NFZ sensing easier and more rapid by naked eyes,only with a low LOD of 0.8117 ppm for MMMs sensor.Notably,by combining multiple experiments with density functional theory(DFT)calculations,the photo-induced electron transfer(PET)quenching mechanism is further elucidated.More importantly,potential practical applications of LCU-111 for latent fingerprint visualization provide lifelike evidences for effective identification of individuals,which can be applied in criminal investigation.

Anion/Cation (H_2PO_4^- and Fe^(3+)) induced dual luminescence quenching effect based on terbium solid sensor

An investigation on the photophysical properties of the newly designed terbium imidazole-4,5-dicarboxylic acid complex encapsulated in the inert matrices (tetraethoxysilane, TEOS) was performed. The composite material was very stable and showed strong green emission in pure water. Interestingly, we discovered that the luminescence of hybrid material was selectively responsive to H2PO4-. 1H-NMR and fluorescence spectra supported that the receptor had strong affinity to dihydrogen phosphate. Meanwhile, the luminescence was quenched by Fe3+ when adding different metal ions such as Fe3+, Pd2+, Cd2+, Co2+ and Mn2+ concomitantly. Moreover, thin film was successfully pre-pared by the same materials and it also exhibited selective recognition behavior to the above two ions.

Nafion-Induced Metal-Metal Interactions in a Platinum(II) Terpyridyl Acetylide Complex:a Luminescent Sensor for Detection of Volatile Organic Compounds

The platinum(II) terpyridyl acetylide complex [Pt(terpy)(C≡CR)]ClO4 (terpy=2,2'∶6'2''-terpyridine, R=CH2CH2CH3) (1) was incorporated into Nafion membranes. At high loading the dry membranes exhibit intense photoluminescence with max at 707 nm from the 3MMLCT state, which was not observed in fluid solution. Upon exposure to the vapor of polar volatile organic compounds (VOC), this photoluminescence was significantly red-shifed. This process was fully reversible when the VOC-incorporated membrane was dried in air. The dramatic and reversible changes in the emission spectra made the Nafion-supported complex as an interesting sensor candi-date for polar VOC.

Hierarchical porous cellulose/lanthanide hybrid materials as luminescent sensor

Photoluminescent hybrid materials containing carboxymethyl cellulose and lanthanide ions（Eu3＋, Tb3＋）were prepared by a facile method under ambient conditions. Lanthanide ions were covalently grafted to the cellulose framework through coordination with the carboxylic groups of the cellulose. Hybrid materials were fabricated as hydrogel and aerogel. As shown by SEM and pore parameters, aerogel materials which were obtained by supercritical CO2 drying show hierarchical porous structure. The photoluminescence spectrum of the hybrid materials shows the characteristic red emission of Eu3＋ ion and green emission of Tb3＋. Further luminescent investigations reveal that these hybrid materials can detect Fe3＋ with relative selectivity and high sensitivity, which suggests that the hybrid materials could be a promising luminescent probe for selectively sensing Fe3＋ ion.

Recent Progresses in Lanthanide Metal-Organic Frameworks(Ln-MOFs) as Chemical Sensors for Ions, Antibiotics and Amino Acids

Various ions and antibiotics,widely used in industry and clinical medicine,respectively,are massively discharged to atmosphere and water,resulting in severe pollutions on environment and potential threats to human health.Besides,amino acids,the primary substances for the establishment of proteins,cells and tissues,are crucial to human health.Therefore,seeking effective and practicable materials to detect aforesaid analytes is vitally meaningful.Metal-organic frameworks centered with lanthanide ions(Ln-MOFs),also known as lanthanide coordination polymers,are considered as a charming category of multi-functional hybrid crystalline materials with fascinating structures and incomparable luminescent characteristics.Benefited from their unique merits,Ln-MOFs have been largely developed as excellent luminescent sensors for fast and efficient sensing various analytes.In this review,we aim to introduce some of the recent researches between 2018 to 2022 on Ln-MOFs applied as chemical sensors for ions,antibiotics and amino acids based on luminescent quenching and enhancing effects,and provide an update and summary for the latest progresses in this field.

Using europium(Ⅲ) complex of 1,4,7,10-tetraazacyclododecane-1,4,7-triacedic acid Eu.DO3A as a luminescent sensor for bicarbonate

Sensing of analyte s in biological fluids and biotechnological production media remains a challenge.He re,the luminescent response of the europium(Ⅲ)complex of 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid(DO3A)to bicarbonate was investigated in detail.The response of Eu.DO3A to changes in bicarbonate concentration was studied in different buffers,and the influence of ionic strength,pH,and specific ions was determined.The response is found to depend on pH and ionic strength,but it is not possible to separate contributions from the sensing event from those in the bicarbonate activity.Prior to demonstrating the ability to determine the bicarbonate concentration in bioproduction media and serum,the influence of competing carboxy anions was evaluated.It is established that while competing anions bind stronger to the responsive complex,at the relevant concentration their contribution to the recorded signal is negligible.We are thus able to conclude that Eu.DO3A is a good platform for building a bicarbonate sensor.

A Water-Stable 3D Eu(Ⅲ)-Organic Framework as a Bi-Functional Ratiometric Luminescent Sensor for Fast, Sensitive and Selective Detection of ODZ and Hg^(2+) in Aqueous Media

The fast,sensitive and selective detection of some antibiotics and heavy metal cations in water is highly desirable for environmental protection and human health,but it is still currently challenging.In this work,a new luminescent Eu(Ⅲ)-based metalorganic framework(MOF),{[(CH_(3))_(2)NH_(2)][Eu(L)2(H_(2)O)_(2)]·xDMF}n(1)[H_(2)L=4,4’-((naphthalene-1,4-dicarbonyl)bis(azanediyl))dibenzoic acid],was solvothermally synthesized.Complex 1 exhibits good water stability and luminescent property and could serve as a bifunctional ratiometric luminescent sensor for fast,sensitive and selective detection of ornidazole(ODZ)and Hg^(2+)in aqueous solution.The corresponding luminescent mechanism has also been discussed.This work indicates that 1 as a promising luminescent material exhibits luminescent quenching behavior for ODZ and luminescent enhancement behavior for Hg^(2+)in H_(2)O,which will promote the practical application of Ln-MOF-based ratiometric luminescent sensors in monitoring antibiotics and metal ions pollutants in the environmental water matrices.

Europium Activated Aluminum Organic Frameworks for Highly Selective and Sensitive Detection of Fe and Cr(Ⅵ) in Aqueous Solution

The aluminum based MOFs compound, MIL-96(Al), has been studied as a luminescence sensor by incorporating of Eu3+ ions, which renders the compound strong red-light emission. The as-synthesized MIL-96(Al):Eu3+ nanocrystals exhibit water dispersibility and environmental stability, which are general requirement for an ideal sensing material. The MIL-96(Al):Eu3+ nanocrystals show excellent selective detection ability on Fe3+ ions in aqueous solution with value of low detection limit 20 μM. Meanwhile, it also exhibits excellent selective detection ability on CrO42- and Cr2O72- in aqueous solution with value of low detection limit 10 and 22 μM, respectively. The results of this study show that MIL-96(Al):Eu3+ nanocrystals could be used as a multi-responsive luminescent senor for Fe3+ and Cr(Ⅵ) species in aqueous solution. The possible luminescence quenching mechanism has also been discussed.

Luminescent gold nanocluster-based sensing platform for accurate H_(2)S detection in vitro and in vivo with improved anti-interference

Gold nanoclusters(Au NCs)are promising luminescent nanomaterials due to their outstanding optical properties.However,their relatively low quantum yields and environment-dependent photoluminescence properties have limited their biological applications.To address these problems,we developed a novel strategy to prepare chitosan oligosaccharide lactate(Chi)-functionalized Au NCs(Au NCs@Chi),which exhibited emission with enhanced quantum yield and elongated emission lifetime as compared to the Au NCs,as well as exhibited environment-independent photoluminescence properties.In addition,utilizing the free amino groups of Chi onto Au NCs@Chi,we designed a FRET-based sensing platform for the detection of hydrogen sulfide(H_(2)S).The Au NCs and the specific H_(2)S-sensitive merocyanine compound were respectively employed as an energy donor and acceptor in the platform.The addition of H_(2)S induced changes in the emission profile and luminescence lifetime of the platform with high sensitivity and selectivity.Utilization of the platform was demonstrated to detect exogenous and endogenous H_(2)S in vitro and in vivo through wavelength-ratiometric and time-resolved luminescence imaging(TLI).Compared to previously reported luminescent molecules,the platform was less affected by experimental conditions and showed minimized autofluorescence interference and improved accuracy of detection.

Porous organic polymer nanotubes as luminescent probe for highly selective and sensitive detection of Fe^(3+)

Two porous organic polymer nanotubes(PNT-2 and PNT-3) were synthesized via Ni-catalyzed Yamamoto reaction, using2,4,6-tris-(4-bromo-phenyl)-[1,3,5]-triazine(TBT) as one monomer, and 2,7-dibromopyrene(DBP) or 1,3,6,8-tetrabromopyrene(TBP) as another monomer. The scanning electron microscope(SEM) images show that both PNT-2 and PNT-3 possess clear hollow tube structures. Luminescent measurements indicate that both PNT-2 and PNT-3 can serve as luminescent probe for highly selective and sensitive detection of Fe^(3+) by luminescent quenching effect. Absorption competition quenching(ACQ) mechanism is also proposed to explain luminescent quenching behavior, i.e., the overlap of the UV-spectra between Fe^(3+) and PNTs causes the energy competition, and therefore leads to luminescent quenching. Moreover, both PNT-2 and PNT-3 still show high selectivity and sensitivity for sensing Fe^(3+) in 10% ethanol aqueous solution, which means that the two porous PNTs are promising candidates as luminescent probes for detecting Fe^(3+) in practical applications.