The recent development of controlling of the triplet excited state of organic chromophores was summarized. Controlling the triplet excited state is very useful, by which various functional organic compounds can be developed. For instance, the activatable PDT photosensitizers, phosphorescent molecular probes, and can be applied in photoswitchable triplet-triplet annihilation (TTA) upconversion. However, by comparison to the controlling of singlet excited state (fluorescence), the study on the controlling of the triplet excited state is rare. Recently there are some reports on triplet state switching by supramolecular or covalent modification methods, based on photophysical processes such as Förster resonance energy transfer (FRET), triplet triplet energy transfer (TTET), photo-induced electron transfer (PET), etc. These reports show that controlling of the triplet excited state is very different from controlling of the singlet excited state. For example, usually the singlet excited state can be quenched by PET effect, but the triplet excited state can not be quenched by PET effect in many cases. This review article summarizes the development of triplet state switching, and will be useful for the molecular design concerning the controlling and application of triplet excited state in functional organic compounds.
Naphthopyran and its derivatives are transitional photochromic materials with low background color, good resistance fatigue and fine contral over fading kinetics. Herein, we introduce the progress of the application of naphthopyran in photochromic fluorescence switching, including hazarding manner, polymers and organic molecules in solutions and films.These researches also explored the potential applications in non-destructive readout and fluorescent images.
Organic photochromic materials have attracted much considerable attention because of their potential promising applications in optical memory and molecular switching devices. Among the various photochromic systems, diarylethenes have broad applications in the photoelectric materials and biomedicine field due to their good thermal stability, excellent fatigue resistance, rapid response, and high sensitivity. In recent years, controllability optical chemical sensors based on diarylethenes have gradually became a hotspot in the field of functional material. This review summarizes the research progress of optical chemical sensors with multiple control function based on diarylethene as a optical control units, and the developing orientation for further research is also presented.
Small molecule α-ketoglutaric acid (α-KA) is a very important product of metabolism in human body, which exhibits direct or indirect relation with many kinds of diseases. A fluorescence resonance energy transfer (FRET) ratiometric probe for α-KA containging rhodamine and BODIPY has been synthesized. As the energy donor, the fluorescence spectrum of BODIPY matches well with the absorption spectrum of rhodamine which is chosen as the energy acceptor. Research shows that the orginal fluorescence spectrum of probe RDM-BO is similar with BODIPY. While the α-KA induces ring-open reacntion with rhodamine unit of RDM-BO, the molecular conjugate is changed, resulting in new fluorescence peaks. The detection limit could reach 3.14 μmol·L-1.
Copper is a highly toxic environmental pollutant, therefore, there is an urgent need to develop new materials for its removal from water. In the present study,new TEMPO oxidized cellulose-based materials were synthesized and investigated as an adsorbent for simple and rapid removal of copper ion[Cu(Ⅱ)] via spectrophotometry. Cellulose was extracted from chemical pulp fiber, TEMPO oxidized, and modified by reaction with three different amino acids (Gly, Lys, His). Compared with TEMPO oxidizedcellulose (TOC), the amino acid modified cellulose (AMC) had better effect on the adsorption of copper ion, in which histidine modified cellulose achieved the best adsorption rate with 97% in low copper concentration. In addition,the AMC dosing amount, initial copper concentration, pH on the adsorption effect were also investigated.The data were analyzed on the basis of variouskinetic and isotherm models, and pseudo-second-order kinetics and Langmuir isotherm were followed for Cu2+ adsorption.
In this paper, we constructed a kind of fluorescent probe based on 3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methylbenzaldehyde for the detection of aluminum ions. The fluorescent probe has high sensitivity and selective detection to aluminum ions, and can display the dual response of color and strong fluorescence change. Research results show that the probe showed very good fluorescence enhancement effect to aluminum ion. Other metal ions in the process of test do not have noticeable interference to the test results. The ratio of fluorescence intensity (I490/I567) with aluminum ion concentration (0-20 μmol/L) shows a good linear relationship between the probe and aluminum. The detection limit is as low as 0.5 μmol/L. Due to its high sensitivity and selectivity, the probe can be used for detection of aluminum ion content in the polluted river.
As a strong oxidant, HClO was widely applied in people everyday life, so it is great important to monitor the concentration of HClO. Herein, we developed a new strategy to resolve the deficiency of photobleaching and poor water-solubility for the current HClO probes. On the basis of the fact that hypochlorite can destroy the conjugated structure of the organic dye, a polystyrene nanoparticle loaded with the Cy7 dye (PS-Cy7) had been designed and synthesized. Moreover, PS-Cy7 with the size of 78 nm was carried out as colorimetric nanoprobe for detection of hypochlorite anion (ClO-). The nanoprobe exhibits good water-solubility and high photostability. The detection limit of PS-Cy7 for hypochlorite in water was 0.22 μmol/L. Furthermore, PS-Cy7 can specifically respond to hypochlorite in presence of other reactive oxygen species. The experimental result demonstrated that PS-Cy7 was a colorimetric nanoprobe with high sensitivity and selectivity of hypochlorite.
Mercury ion (Ⅱ) is known as one of the most toxic metal ions both for humans and the environment. In this work, a new fluorescent probe based on dansyl dye was designed and synthesized, and its determining property towards metal cations was investigated. The result indicated that this dansyl-based fluorescent probe possessed high selectivity and good sensitivity towards mercury ion (Ⅱ) in an aqueous media without any interference from other metal cations. It was worth mentioning that the detection limit of mercury ion (Ⅱ) can reach to 2.1×10-8 mol/L. Such low detection limit and good water-solubility supported this probe could be used to visualize the level of mercury ion (Ⅱ) in living cells. Furthermore, the bioimaging experiment confirmed that this probe had good membrane permeability and biocompatibility.
The paper describes a systematic study on the synthesis of Zn-Al layered double hydroxides (LDHs). Different guest species intercalated LDHs have been synthesized by the methods of coprecipitation and ion exchange, respectively, such as o-, m-, p-nitrobenzoic acid. PXRD, FTIR, UV/Vis and theoretical calculation were used to study the photosensitivity, and the possible mechanism was proposed, which provides a theoretical basis and a prerequisite for the application of the new photosensitive materials.
With the development of technology and the progress of society, the food safety problem gains increasing attention. Saccharin sodium, as one kind of food additives, is occasionally reported as illegal additions. Thus it is necessary to find a rapid and accurate method for the detection of saccharin sodium. The fluorescence molecular probe has gained a widely application in analytical chemistry determination due to its advantages such as high sensitivity, good selectivity and short response time. In this paper, a novel compound contained an anthracene fluorophore and an aza-15-crown-5 group was designed and synthesized. Based on the molecular recognition, the compound could specifically recognize the saccharin sodium in solution, resulting in the changes of fluorescence intensity.What's more,the phenomenon is visible and easy to be observed. The method provides a practicable strategy for rapid determination saccharin sodium in food.
Theformaldehyde had been identified as a carcinogenic and teratogenic molecule. To solve the problems of inconvenient analysis techniques, a novel probe of (km2bn) basedon the structure of benzodiazepin was prepared, which could be assembled to a 1D molecular line (km2bn·H2O) by water. This supramolecular material could react with theformaldehyde and yield a colored polymer through Hantzsch reaction. The formaldehyde sensing film was prepared using the sol-gel method. The chemochromicdata were collected by the CCD and then processed by thecomputer and found thelinear correlation with the concentrations of formaldehyde.