查看更多>>摘要：Supercritical carbon dioxide (scCO2) is commonly used as an excellent solvent in chemical reactions and dyeing fields because of its advantages. In this work, three coumarin and 1,8-naphthalimide fluorescent dyes (DAMC, NP-NH, and NP-dimethyl) were successfully constructed on the basis of the Au/titanium dioxide (Au/TiO2) catalytic reduction of nitro in scCO2 instead of SnCl2/hydrochloric acid solution, and their structures were confirmed correctly by mass spectrometry (MS) and nuclear magnetic resonance (NMR). The cleaner synthesis and dyeing polyester fabrics of coumarin derivative (DAMC) in the presence or absence of N-methyl-pyrrolidone (NMP) were first studied by employing stepwise and synchronous methods. All results for DAMC indicated that the synchronous synmesis and dyeing method is more beneficial. Here, the synchronous synthesis and dyeing polyester fabrics of 1,8-naphthalimide derivatives (NP-NH and NP-dimethyl) in scCO2 were also investigated. Through the comprehensive analysis of color strength (K/S) value and fixation rate, the optimal temperatures and pressures of synthesis and dyeing for NP-NH and NP-dimethyl were obtained in the absence or presence of NMP. The dyed fabrics with NP-NH and NP-dimethyl exhibited yellow or yellowish-brown in daylight and bright fluorescent yellowish-green in ultraviolet light. All results showed that the clean production of fluorescent dyes (DAMC, NP-NH, and NP-dimethyl) can be realized by the hydrogenation of nitro with efficient Au/TiO2 catalyst in scCO2, meanwhile, the synchronous synthesis and dyeing method was proposed for the synthesized dyes. The realization of synchronous synthesis and dyeing fabrics for fluorescent dyes in scCO2 is an effective way to prevent environment pollution brought by the processes of synthesis and dyeing. Thus, the constructing and dyeing strategy of fluorescent dyes will be beneficial to the sustainable development of environment.
Timofey D. MoseevMikhail V. VaraksinElizaveta A. Virlova
11页
查看更多>>摘要：A series of novel push-pull fluorophores based on 2H-imidazole scaffold bearing perfluorophenyl substituent and extended electron-donating conjugating π-system were synthesized. In particular, the Pd-catalyzed Suzuki-Miyaura coupling reactions were exploited as a main synthetic strategy to modify 4-(4-bromophenyl)-2,2-dimethyl-5-(pentafluorophenyl)-2H-imidazole with various electron-donating functionalities. The comprehensive photophysical studies were carried out for the synthesized fluorophores, including the analysis of absor-bance and emission spectra and determination of absolute quantum yields. The designed compounds were found to have a strong emission in the range of 470-610 nm depending on both the nature of solvent used and the structure of electron-donating group attached to the aryl moiety. The pH effect of the aqueous-organic mixture buffer solution on the fluorescent characteristics of the synthesized compounds was established and the deprotonation-induced "turn-on" pH sensing mechanism supported by DFT calculations was proposed for the first time. Particularly, the sequence of deprotonation was confirmed, and free energies for all N-protonated and N-proton-free forms were calculated. No toxic effect on the human embryonic kidney cells (HEK-293) at concentration of ≤512 μM was observed in vitro experiments. In addition, new opportunities for the practical application of these molecular ensembles were demonstrated in case of fluorometric determination of the pH both in model solutions and real saliva probes, with 3-(4-(2,2-dimethyl-5-(pentafluorophenyl)-2H-imidazole-4-yl)phenyl)-9-phenyl-9H-carbazole being used.
查看更多>>摘要：1,3,4-Oxadiazole was modified with phenyl and fluorenyl groups at the 2- and 5- positions, respectively, which can be used as a new cyclometalating ligand to synthesize a series of novel Ir(III) complexes. In the preparation of picolinate iridium(III) complexes [Ir(N^C)2(pic)] (N^C = cyclometalating ligand, pic = picolinate), two isomeric products were isolated unexpectedly, among which, the iridium(III) center in one product was cyclometalated at the phenyl site of two cyclometalating ligands. In the other, the cyclometalations occurred at the fluorenyl site and phenyl site from the two ligands respectively. Another possible isomer completely coordinated by two fluorenyl groups was not obtained owing to the very low product yield. The obtained two isomers were characterized by ~1H NMR and MALDI-TOF. Single-crystal X-ray structural analysis of their methyl-substituted analogues confirmed the different coordination modes. Electrochemical and photophysical investigation revealed that the excited-state properties of the two isomers were closely related to their coordination modes, and thus a facile strategy was provided that is to regulate luminescent and electrochemical properties by easily changing coordination sites. Both isomers were used to fabricate high performance electroluminescence devices using spin-coating techniques. The unsymmetric coordination complex FP-DP exhibited the highest performance among all the devices, achieving a maximum current efficiency of 12.16 cd/A and luminance of 7037.69 cd/m~2.
查看更多>>摘要：Two europium-postdoped metal organic frameworks (MOFs) Eu~(3+)@1 and Eu~(3+)@2 [1:{[Zn2(bta)(bpy)(H2O)2]· 2H2O}n, 2:{[Ni(bta)Cbpy)(H2O)2][Ni(bpy)·(H2O)4]·4H2O}n (H4bta = 1, 2, 3, 5-benzenetetracarboxylic acid, bpy = 4, 4'-dipyridine)] were prepared by hydrothermal synthesis and post-synthesis modification. MOFs 1-2 are all three-dimensional network structure connected by (bta)4" and bpy ligands. Eu~(3+)@1 and Eu~(3+)@2 in aqueous solution can achieve the quantitative detection of 2, 4, 6-trinitrobenzene (TNP), tetracycline (TC) and pesticides with high sensitivity and selectivity. In particular, when the volume of TNP increases to 50 μL , the luminescence quenching rate of Eu~(3+)@2 can reach 99.7% and the LOD for TNP can reach 78 nM. Interestingly, Eu~(3+)@1 has a good response to PTH (Pyrimethanil), while Eu~(3+)@2 has a good selectivity to FLU (Fluazinam), and both can be used for rapid in-situ imaging detection of simulated pesticide residues on fresh vegetables. Under UV lamp, Eu~(3+)@1 showed a significant fluorescence quenching effect on PTH in beans, while the fluorescence quenching effect of Eu~(3+)@2 on FLU on cabbage was obvious. Surprisingly, two kinds of composite materials can be used as anti-counterfeiting ink functional material with strong anti-counterfeiting ability and long term stability.
查看更多>>摘要：The initiation and propagation of cancer is closely associated with bacterial infection, which generally requires the simultaneous usage of anticancer drugs and antibiotics. However, the adverse effects have increased too much due to the multiple use of chemodrugs. To tackle this problem, a successful attempt has been made by developing two BODIPY-based cationic photosensitizers, 1BDPC-Py and 1BDPC-TPP, for treating both cancer and bacterial infection. Optimization of the basic design of these photosensitizers resulted in the red-light absorption, improved ~1O2 generation yield, outstanding therapeutic effects and optical physical properties for excellent imaging. The decorated cationic groups grant some highly favorable features, such as a mediated hydrophilic-lipophilic balance for improving cell penetrability, specific mitochondrial anchoring for enhanced PDT and the increased attraction towards bacterial cells for efficient photoinactivation. As a result, these photosensitizers exhibited extremely high phototoxicity and phototoxic index (PI) against breast cancer cells along with promising photodynamic activity against two bacterial species and their corresponding antibiotic resistant strains. For example,1BDPC-Py and 1BDPC-TPP have the values of 7.8 nM and 30 nM for IC_(50) along with 1539 and 720 for PI against the MCF-7 cells, respectively. Similarly, both 1BDPC-Py and 1BDPC-TPP decreased the viability of S. aureus and E. coli to almost 0% at 100 nM and 400 nM, respectively. Thus, to the best of our knowledge, both of these are the first excitable BODIPY-based photosensitizers in the therapeutic window for the precise treatment of both cancer and bacterial infection.
查看更多>>摘要：Two stable three-dimensional lanthanide metal-organic frameworks, Ln-MOFs of [M2O(BDCPO)_(1.5)(H2O)7]·2H2O (Eu for CUST-621, Tb for CUST-622) are successfully constructed using π-electron riched ligand N,N'-bis(2,4-dicarboxyphenyl)-oxalamide (H6BDCPO) and Eu and Tb metal ions under solvothermal conditions. The appropriate chromophores in ligands can effectively sensitize Ln~(3+) ions, resulting in luminescence emission. The crystal structures are determined by single X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, infrared spectrophotometer and luminescence measurements. Triple emission centers are successfully designed and realized the solid-state white light (SSWL) performance, whose CIE coordinates are close to ideal white light (0.32, 0.33). Furthermore, the temperature sensitivity tests indicate that the two materials can be used to sense the temperature in the range of 303-423 K with remarkable color change. The maximum sensitivity are 6.86% K~(-1) and 7.73% K~(-1) at 423 K, respectively. Moreover, CUST-621 and CUST-622 can be used as multi-responsive luminescence sensors to Fe~(3+) and Cr2O7~(2-), with high sensitivity, long-time stability and remarkable selectivity with resistance to interference from other ions. This work supply a general way to construct Ln-MOFs materials for multifunctional luminescence properties for sensing fields.
查看更多>>摘要：1,1-dicyanovinyl push-pull dye PTTCN undergoes rapid and reversible aza-Michael addition with volatile primary aliphatic amines in solution in DMSO, yielding highly fluorescent imine derivatives. This reaction is accompanied by a dramatic colour change as well as a strong increase in fluorescence (1200-fold increase) allowing sensitive turn-on detection of primary amine in solution. In the solid state, PTTCN is emissive and reaction with primary amine vapours results in a shift in fluorescence and a possible ratiometric detection of primary amines. The selectivity is excellent for primary amines over secondary, tertiary and aromatic amines as well as over thiols and fluorescence spectroscopy allows to discriminate between primary amines and other nitrogen nucleophiles such as hydrazine and ammonia. Finally, we show as proof-of-concept that the fluorescence turn-on reaction can be used in response to the vapours of volatile amines released during food spoilage.
查看更多>>摘要：Although neutral luminescent radicals have arisen much attention recently, their applications in fluorescence imaging are rarely reported due to their insolubility in water and weak luminescence in polar solvents. Herein, we encapsulated a luminescent radical and its precursor into nanoparticles (NPs) by an amphiphilic polymer matrix, DSPE-PEG_(2000), to avoid aggregation-caused quenching and poor solubility in water to further achieve its application in cell-imaging. The obtained radical NPs exhibited strong red emission, excellent stability and remarkable biocompatibility under physiological conditions. The radical NPs were incubated with live HCT116 cells and showed good cellular uptake, thus making fluorescence imaging possible in vitro. The results confirm the feasibility of stable neutral luminescent radical as a promising candidate for the application in fluorescence imaging.
查看更多>>摘要：A novel benzofuranone fluorescent probe, BFO-SFT, for monitoring sulfite in living cells and mice is described which operates over a wide pH range and exhibits a red-shifted emission maximum. The response of the probe BFO-SFT was relatively rapid (within 20 min) and exhibited a good linear correlation of 0-10 Eq (100 μM) with reliable accuracy (R~2 = 0.9934). The probe also showed high sensitivity (Limit of detection =152 nM) and selectivity. With low cytotoxicity, BFO-SFT was successfully applied into the biological imaging of sulfite in living MCF-7 cells and in BALB/C Nude mice.
查看更多>>摘要：Cyanidin-3-diglycoside-5-glycoside, the major fraction of red cabbage anthocyanins, is influenced by environmental factors such as pH, oxygen, enzymes, light, and high temperatures which make its encapsulation necessary. In this study, ethanol: water (75.5: 24.5%) acidified with 0.15% citric acid was found to be the optimum solvent regarding highest anthocyanin and phenol extraction as well as antioxidant capacity. The anthocyanin rich extract was loaded in phosphatidylcholine-based liposome prepared based on lyophilized monophase solution method using tert-butyl alcohol-water cosolvent system. The particle size of nanoliposomes ranged from 37.12 to 56.1 nm with zeta potentials of about -39 mV. Encapsulation efficiency (EE) values of the prepared nanoliposomes was 74% ± 3.5. During 21 days storage, anthocyanin loaded nanoliposomes were more stable at 4 °C in comparison with 25 °C. The best fitted models at hydrophilic and lipophilic media were zero order and Weibull kinetic, respectively. Spherical morphology was obtained for liposome containing red cabbage extract through transmission electron microscopy, FTIR spectroscopy demonstrated interaction between red cabbage anthocyanin with liposome structure. Overall, lyophilized nanoliposome can extend application of red cabbage extract in functional food formulations.
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