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2018 Volume 35 Issue 1
2018, 35(1): 1-20
doi: 10.11944/j.issn.1000-0518.2018.01.170328
Abstract:
Fluorescent probes are gaining more and more attention because of their high selectivity, sensitivity, fast response, simple operation and low detection limit. Compounds based on excited state intramolecular proton transfer(ESIPT) have special excited state photophysical properties, such as high fluorescence quantum yield and large Stokes shift. For fluorescent molecules, the larger Stokes shift can reduce the interference caused by self-absorption and internal filtration, and enhance light-fastness of the molecules and facilitate the emitting of fluorescence. In this review, we summarized these ESIPT fluorescent probes from the classification of targets. The targets for detection were divided into ions(including metal cations and anions), neutral small molecules and biological macromolecules. The existing problems and application prospects of fluorescent molecules based on ESIPT were commented.
Fluorescent probes are gaining more and more attention because of their high selectivity, sensitivity, fast response, simple operation and low detection limit. Compounds based on excited state intramolecular proton transfer(ESIPT) have special excited state photophysical properties, such as high fluorescence quantum yield and large Stokes shift. For fluorescent molecules, the larger Stokes shift can reduce the interference caused by self-absorption and internal filtration, and enhance light-fastness of the molecules and facilitate the emitting of fluorescence. In this review, we summarized these ESIPT fluorescent probes from the classification of targets. The targets for detection were divided into ions(including metal cations and anions), neutral small molecules and biological macromolecules. The existing problems and application prospects of fluorescent molecules based on ESIPT were commented.
2018, 35(1): 21-27
doi: 10.11944/j.issn.1000-0518.2018.01.170338
Abstract:
As a new type of protein redox-based post-translational modification acting as a molecular switch for the modulation of protein functions, the protein methionine sulfoxidation not only acts as a biomarker of cellular oxidative stress, but also regulates redox signaling transductions, which is thus closely related to many diseases, especially neurodegenerative diseases. In many organisms, the only molecule known to reduce the methionine sulfoxide is methionine sulfoxide reductases(Msrs), which can repair the oxidation damage and recover the function of protein thus play important roles in cellular redox balance regulations. In this article, we will first discuss the structure and catalytic mechanism of protein methionine sulfoxide(MetO) and Msrs, then review the recently developed fluorescent probes for MetO/Msrs type A(MsrA), and give a brief prospect at the last.
As a new type of protein redox-based post-translational modification acting as a molecular switch for the modulation of protein functions, the protein methionine sulfoxidation not only acts as a biomarker of cellular oxidative stress, but also regulates redox signaling transductions, which is thus closely related to many diseases, especially neurodegenerative diseases. In many organisms, the only molecule known to reduce the methionine sulfoxide is methionine sulfoxide reductases(Msrs), which can repair the oxidation damage and recover the function of protein thus play important roles in cellular redox balance regulations. In this article, we will first discuss the structure and catalytic mechanism of protein methionine sulfoxide(MetO) and Msrs, then review the recently developed fluorescent probes for MetO/Msrs type A(MsrA), and give a brief prospect at the last.
2018, 35(1): 28-39
doi: 10.11944/j.issn.1000-0518.2018.01.170363
Abstract:
Aptamers are oligonucleotides selected through an in vitro method known as systematic evolution of ligands by exponential enrichment(SELEX), which can recognize target with high specificity and high affinity. Aptamers have attracted wide attention because of their intrinsic advantages including simple synthesis, low molecular mass, high chemical stability, easy biochemical modification and so on. Aptamers can fold into specific two-dimensional or three-dimensional configurations and specifically bind with their targets. With appropriate signal transduction mechanism, aptamers can provide ideal molecular recognition and detection probes for biological research. Fluorescence is a type of detection technology that has several superiorities of high sensitivity, high resolution and easy multiplex detection. With the combination of the molecular recognition capability of aptamers and the outstanding detection performance of fluorescence technology, the aptamer-based fluorescence probes have been widely used in the study of life science. This review highlights the major progress of aptamer-based fluorescence probes in both bioanalysis and bioimaging area, and discusses the current limitations of aptamer probe for applications.
Aptamers are oligonucleotides selected through an in vitro method known as systematic evolution of ligands by exponential enrichment(SELEX), which can recognize target with high specificity and high affinity. Aptamers have attracted wide attention because of their intrinsic advantages including simple synthesis, low molecular mass, high chemical stability, easy biochemical modification and so on. Aptamers can fold into specific two-dimensional or three-dimensional configurations and specifically bind with their targets. With appropriate signal transduction mechanism, aptamers can provide ideal molecular recognition and detection probes for biological research. Fluorescence is a type of detection technology that has several superiorities of high sensitivity, high resolution and easy multiplex detection. With the combination of the molecular recognition capability of aptamers and the outstanding detection performance of fluorescence technology, the aptamer-based fluorescence probes have been widely used in the study of life science. This review highlights the major progress of aptamer-based fluorescence probes in both bioanalysis and bioimaging area, and discusses the current limitations of aptamer probe for applications.
2018, 35(1): 40-45
doi: 10.11944/j.issn.1000-0518.2018.01.170317
Abstract:
A kind of fluorescence probe based on (R)-2, 2'-dihydroxy-[1, 1'-binaphthalene]-3-carboxaldehyde was constructed. The structure was characterized by hydrogen/carbon nuclear magnetic resonance spectroscopy(1H NMR, 13C NMR) and mass spectrometry(MS). The results show that the fluorescent probe can detect arginine in a sensitive and highly selective manner with a double response of color and intense fluorescence. The corresponding fluorescence enhancement ratio is in good linear relation with the concentration of arginine(0~30 μmol/L), the correlation coefficient R2 is 0.9914 and the lowest detection limit is 1.3 μmol/L. In addition, the addition of arginine also caused the chiral structure of the probe to deflect, and the changes of binaphthol derivative axial chiral were verified by the changes of the circular dichromatic spectrum.
A kind of fluorescence probe based on (R)-2, 2'-dihydroxy-[1, 1'-binaphthalene]-3-carboxaldehyde was constructed. The structure was characterized by hydrogen/carbon nuclear magnetic resonance spectroscopy(1H NMR, 13C NMR) and mass spectrometry(MS). The results show that the fluorescent probe can detect arginine in a sensitive and highly selective manner with a double response of color and intense fluorescence. The corresponding fluorescence enhancement ratio is in good linear relation with the concentration of arginine(0~30 μmol/L), the correlation coefficient R2 is 0.9914 and the lowest detection limit is 1.3 μmol/L. In addition, the addition of arginine also caused the chiral structure of the probe to deflect, and the changes of binaphthol derivative axial chiral were verified by the changes of the circular dichromatic spectrum.
2018, 35(1): 46-52
doi: 10.11944/j.issn.1000-0518.2018.01.170340
Abstract:
A quinoline substituted boron dipyrromethene(BODIPY) based probe(BHQ) was synthesized and characterized by nuclear magnetic resonance spectroscopy(NMR) and high resolution mass spectrometer(HRMS). The probe shows significant enhancement of fluorescence intensity in the presence of Fe3+ in aqueous solution. The probe exhibits fast response, high sensitivity and high selectivity toward Fe3+, while other common metal ions do not show significant interference. The binding between the probe and Fe3+ has been found to be in 1:1 mole ratio based on Job's plot. This result suggests that the probe BHQ has potential application in the determination of Fe3+ ions.
A quinoline substituted boron dipyrromethene(BODIPY) based probe(BHQ) was synthesized and characterized by nuclear magnetic resonance spectroscopy(NMR) and high resolution mass spectrometer(HRMS). The probe shows significant enhancement of fluorescence intensity in the presence of Fe3+ in aqueous solution. The probe exhibits fast response, high sensitivity and high selectivity toward Fe3+, while other common metal ions do not show significant interference. The binding between the probe and Fe3+ has been found to be in 1:1 mole ratio based on Job's plot. This result suggests that the probe BHQ has potential application in the determination of Fe3+ ions.
2018, 35(1): 53-59
doi: 10.11944/j.issn.1000-0518.2018.01.170344
Abstract:
Near-infrared fluorescence squaraine/polyvinyl alcohol(PVA) binary and squaraine/hydrophilic graphene/PVA ternary polymers with stronger fluorescence(660~665 nm) intensity, photostability and thermostability were designed and synthesized from a squaraine dye, water soluble graphene and PVA. Compared to those in water, the maximum UV-Vis absorption and fluorescence wavelengths of the squaraine in PVA showed red shifts, and the fluorescence intensity and photostability were significantly enhanced. The presence of the graphene improved the photostability and thermostability of the material.
Near-infrared fluorescence squaraine/polyvinyl alcohol(PVA) binary and squaraine/hydrophilic graphene/PVA ternary polymers with stronger fluorescence(660~665 nm) intensity, photostability and thermostability were designed and synthesized from a squaraine dye, water soluble graphene and PVA. Compared to those in water, the maximum UV-Vis absorption and fluorescence wavelengths of the squaraine in PVA showed red shifts, and the fluorescence intensity and photostability were significantly enhanced. The presence of the graphene improved the photostability and thermostability of the material.
2018, 35(1): 60-67
doi: 10.11944/j.issn.1000-0518.2018.01.170048
Abstract:
The fluorescence of Rhodamine B was quenched due to the surface energy transfer from Rhodamine B to silica supported gold nanoparticle surface. The Stern-Volmer quenching constant of the gold nanoparticles was 4.3×103 L/mol in this system. While, the fluorescence of Rhodamine B recovered after the addition of thiols due to the strong affinity of thiol to gold nanoparticles which obstructed the energy transfer between Rhodamine B and gold nanoparticles. As the unique response of Rhodamine B-Au-SiO2 system to thiols, it provides a simple analytical method for the detection of thiols. Moreover, Au-SiO2 becomes a recyclable probe because of the stabilization of silica support.
The fluorescence of Rhodamine B was quenched due to the surface energy transfer from Rhodamine B to silica supported gold nanoparticle surface. The Stern-Volmer quenching constant of the gold nanoparticles was 4.3×103 L/mol in this system. While, the fluorescence of Rhodamine B recovered after the addition of thiols due to the strong affinity of thiol to gold nanoparticles which obstructed the energy transfer between Rhodamine B and gold nanoparticles. As the unique response of Rhodamine B-Au-SiO2 system to thiols, it provides a simple analytical method for the detection of thiols. Moreover, Au-SiO2 becomes a recyclable probe because of the stabilization of silica support.
2018, 35(1): 68-74
doi: 10.11944/j.issn.1000-0518.2018.01.170030
Abstract:
Ten novel amino acid derived chiral stationary phases(CSPs), including eight amino acid modified triazine derived CSPs(CSP-1~CSP-8) and two N-p-methylbenzoyl L-amino acid CSPs(CSP-9~CSP-10), were prepared from L-valine and L-alanine. The chiral recognition ability of these CSPs was evaluated for regioisomers of o-, m-, p-nitrophenol and six racemates of naproxen ethyl ester, propiconazole, difenoconazole, tebuconazole, hexaconazole, 1, 1'-bi-2-naphthol, under normal phase mode. The results show that CSP-1~CSP-3 and CSP-6~CSP-8 exhibit good selectivity for three regioisomers of nitrophenol. The CSPs obtained from L-alanine show better enantioselective recognition toward the racemates, which leads to a baseline separation of naproxen ethyl ester on CSP-6. Meanwhile, the binding mode and association energy of L-alanine three-substituted triazine derivative CSP Ⅵ with R or S naproxen ethyl ester were investigated by computational simulation with Gaussian 09 software, and hydrogen bonding was found to be a significant factor on the enantioselective recognition.
Ten novel amino acid derived chiral stationary phases(CSPs), including eight amino acid modified triazine derived CSPs(CSP-1~CSP-8) and two N-p-methylbenzoyl L-amino acid CSPs(CSP-9~CSP-10), were prepared from L-valine and L-alanine. The chiral recognition ability of these CSPs was evaluated for regioisomers of o-, m-, p-nitrophenol and six racemates of naproxen ethyl ester, propiconazole, difenoconazole, tebuconazole, hexaconazole, 1, 1'-bi-2-naphthol, under normal phase mode. The results show that CSP-1~CSP-3 and CSP-6~CSP-8 exhibit good selectivity for three regioisomers of nitrophenol. The CSPs obtained from L-alanine show better enantioselective recognition toward the racemates, which leads to a baseline separation of naproxen ethyl ester on CSP-6. Meanwhile, the binding mode and association energy of L-alanine three-substituted triazine derivative CSP Ⅵ with R or S naproxen ethyl ester were investigated by computational simulation with Gaussian 09 software, and hydrogen bonding was found to be a significant factor on the enantioselective recognition.
2018, 35(1): 75-81
doi: 10.11944/j.issn.1000-0518.2018.01.170040
Abstract:
The extraction behaviors of Fe(Ⅲ) in the preparation of high purity aluminum chloride with N, N, N', N'-tetrabutyl malonamide(TBMA), N, N, N', N'-tetraoctyl-3-oxy-glutaramide(TODGA) and methyl isobutyl ketone(MIBK) have been investigated. The results show that the extraction efficiency of Fe(Ⅲ) with TBMA or MIBK is 90% when the concentration of hydrochloric acid in the aluminum chloride solution is 4 mol/L. TODGA shows an excellent separation performance. When the concentrations of Al3+, Fe3+, and HCl are 2.0 mol/L, 0.0036 mol/L(0.2 g/L), and 1.2 mol/L, respectively, in the solution of aluminum chloride, the extraction efficiency of Fe3+ is more than 99.9% with 0.20 mol/L TODGA in cyclohexane or n-dodecane. After several extractions, the iron impurities in the aluminum chloride can be deeply removed and the iron content in the solution is lower than 0.01 mg/L, indicating that it has potential application in industrial production.
The extraction behaviors of Fe(Ⅲ) in the preparation of high purity aluminum chloride with N, N, N', N'-tetrabutyl malonamide(TBMA), N, N, N', N'-tetraoctyl-3-oxy-glutaramide(TODGA) and methyl isobutyl ketone(MIBK) have been investigated. The results show that the extraction efficiency of Fe(Ⅲ) with TBMA or MIBK is 90% when the concentration of hydrochloric acid in the aluminum chloride solution is 4 mol/L. TODGA shows an excellent separation performance. When the concentrations of Al3+, Fe3+, and HCl are 2.0 mol/L, 0.0036 mol/L(0.2 g/L), and 1.2 mol/L, respectively, in the solution of aluminum chloride, the extraction efficiency of Fe3+ is more than 99.9% with 0.20 mol/L TODGA in cyclohexane or n-dodecane. After several extractions, the iron impurities in the aluminum chloride can be deeply removed and the iron content in the solution is lower than 0.01 mg/L, indicating that it has potential application in industrial production.
2018, 35(1): 82-88
doi: 10.11944/j.issn.1000-0518.2018.01.170336
Abstract:
By solvothermal reaction of Eu(NO3)3 6H2O with 2-(2-bromophenyl)-1H-imidazole-4, 5-dicarboxylic acid (o-BrPhH3IDC) in the presence of terephthalic acid, a three-dimensional supramolecular complex (H3O)[Eu(o-BrPhH2IDC)4](1) was prepared. The crystal structure of complex 1 was determined by single crystal X-ray diffraction. The results show that complex 1 crystallizes in the cubic system, Ⅰ-43d space group, and the central europium ion is in a eight-coordinate system. The solid-state fluorescence of complex 1 reveals that complex 1 exhibits a characteristic europium emission spectra at the excitation wavelength of 395 nm which implies that the organic ligand has a good antenna effect and a good sensitization effect on europium ion.
By solvothermal reaction of Eu(NO3)3 6H2O with 2-(2-bromophenyl)-1H-imidazole-4, 5-dicarboxylic acid (o-BrPhH3IDC) in the presence of terephthalic acid, a three-dimensional supramolecular complex (H3O)[Eu(o-BrPhH2IDC)4](1) was prepared. The crystal structure of complex 1 was determined by single crystal X-ray diffraction. The results show that complex 1 crystallizes in the cubic system, Ⅰ-43d space group, and the central europium ion is in a eight-coordinate system. The solid-state fluorescence of complex 1 reveals that complex 1 exhibits a characteristic europium emission spectra at the excitation wavelength of 395 nm which implies that the organic ligand has a good antenna effect and a good sensitization effect on europium ion.
2018, 35(1): 102-108
doi: 10.11944/j.issn.1000-0518.2018.01.170034
Abstract:
To obtain thermosensitive and injectable hydrogels, hydrotalcite(LDHs) and N-isopropylacrylamide(NIPA) were used to synthesize a series of PNIPA/LDHs hydrogels by free radical polymerization. The properties of PNIPA/LDHs hydrogels were characterized by thermal gravimetric analyzer(TGA), differential scanning calorimetry(DSC) and scanning electronic microscopy(SEM). The results show that the synthesized hydrogels have a reversible sol-gel transformation around 33℃. LDHs mass ratios have no influence on the temperature and time of gelation. The thermal stability of PNIPA/LDHs is remarkably increased by the addition of LDHs. The endothermic peak of PNIPA/LDHs hydrogels increases with the increase of LDHs mass ratios and the molar ratio of Mg to Al. PNIPA/LDHs hydrogels have porous structures.
To obtain thermosensitive and injectable hydrogels, hydrotalcite(LDHs) and N-isopropylacrylamide(NIPA) were used to synthesize a series of PNIPA/LDHs hydrogels by free radical polymerization. The properties of PNIPA/LDHs hydrogels were characterized by thermal gravimetric analyzer(TGA), differential scanning calorimetry(DSC) and scanning electronic microscopy(SEM). The results show that the synthesized hydrogels have a reversible sol-gel transformation around 33℃. LDHs mass ratios have no influence on the temperature and time of gelation. The thermal stability of PNIPA/LDHs is remarkably increased by the addition of LDHs. The endothermic peak of PNIPA/LDHs hydrogels increases with the increase of LDHs mass ratios and the molar ratio of Mg to Al. PNIPA/LDHs hydrogels have porous structures.
2018, 35(1): 109-115
doi: 10.11944/j.issn.1000-0518.2018.01.170025
Abstract:
A high performance flexible polymer solar cells(PSCs) are obtained by using a flexible, transparent composite electrode based on silver nanowire(AgNW) with doctor blading method. The AgNW-based flexible composite film(APA) consisting of AgNWs, polyvinyl butyral(PVB) and Al-doped ZnO(AZO) nanoparticles was readily prepared by multi-layer doctor blading on the poly(ethylene terephthalate)(PET) substrate at moderate temperature. The transparent APA composite film prepared on the PET substrate exhibits superior opto-electrical properties with a high transmittance of 90.90% at 550 nm and a low sheet resistance of 13.01 Ω/sq. The flexible PSCs employing the transparent APA/PET substrate obtain power convention efficiency(PCE) of 5.47%. Moreover, the PCE falls only 14% after bending for 1000 cycles with a bending radius of 5 mm.
A high performance flexible polymer solar cells(PSCs) are obtained by using a flexible, transparent composite electrode based on silver nanowire(AgNW) with doctor blading method. The AgNW-based flexible composite film(APA) consisting of AgNWs, polyvinyl butyral(PVB) and Al-doped ZnO(AZO) nanoparticles was readily prepared by multi-layer doctor blading on the poly(ethylene terephthalate)(PET) substrate at moderate temperature. The transparent APA composite film prepared on the PET substrate exhibits superior opto-electrical properties with a high transmittance of 90.90% at 550 nm and a low sheet resistance of 13.01 Ω/sq. The flexible PSCs employing the transparent APA/PET substrate obtain power convention efficiency(PCE) of 5.47%. Moreover, the PCE falls only 14% after bending for 1000 cycles with a bending radius of 5 mm.
2018, 35(1): 116-122
doi: 10.11944/j.issn.1000-0518.2018.01.170016
Abstract:
Nitrogen-doped carbon-coated lithium titanate(Li4Ti5O12/NC) composites with high performance were prepared via the sol-gel method by using tetrabutyl titanate as the titanium source, lithium monohydrate as the source of lithium, citric acid as carbon source and carbamide as the source of nitrogen. The composites were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Focuier transform infrared spectrometer(IR), thermal gravimetric analyzer(TG), scanning electron microscoy(SEM) and transmission electron microscopy(TEM). The results show that the composites are consisted of Li4Ti5O12 with a NC coating layer. The Li4Ti5O12/NC material with 9.48% of NC exhibits a better electrochemical performance. It delivers a capacity of 212.9 mA·h/g at the first discharge under 1C, after 100 cycles at 1C, it still retains a capacity of 160.1 mA·h/g. The NC coating does not change the material's morphology, but inhibits the growth of composite particles and increases the active site for Li+ ion insertion/extraction, and thus improves the rate capacity and electronic conductivity.
Nitrogen-doped carbon-coated lithium titanate(Li4Ti5O12/NC) composites with high performance were prepared via the sol-gel method by using tetrabutyl titanate as the titanium source, lithium monohydrate as the source of lithium, citric acid as carbon source and carbamide as the source of nitrogen. The composites were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Focuier transform infrared spectrometer(IR), thermal gravimetric analyzer(TG), scanning electron microscoy(SEM) and transmission electron microscopy(TEM). The results show that the composites are consisted of Li4Ti5O12 with a NC coating layer. The Li4Ti5O12/NC material with 9.48% of NC exhibits a better electrochemical performance. It delivers a capacity of 212.9 mA·h/g at the first discharge under 1C, after 100 cycles at 1C, it still retains a capacity of 160.1 mA·h/g. The NC coating does not change the material's morphology, but inhibits the growth of composite particles and increases the active site for Li+ ion insertion/extraction, and thus improves the rate capacity and electronic conductivity.
2018, 35(1): 89-101
doi: 10.11944/j.issn.1000-0518.2018.01.170031
Abstract:
Mononuclear nickel complexes[(2, 6-R2-C6H3)NC(H)(3-Ph-5-PhCOO-2-O-C6H2)-κ2-N, O]Ni(CH3)(pyridine)](R=iPr; 3, 5-tBu2C6H3)(Ni1~Ni2) and binuclear nickel complex(Ni3) were synthesized, characterized and applied in ethylene (co)polymerization. As single-component catalysts, all these complexes are capable of converting ethylene to branched polyethylenes(PE) with moderate relative molecular mass. The electron-donating group PhCOO-facilitates the initiation of catalyst Ni1, leading to better catalytic activity at low temperature compared to nickel methyl pyridine comples(Ni0). Introducing bulky 2, 6-(3, 5-(t-Bu)2C6H3)2C6H3N-moiety, the activities of Ni2 up to 1.8×106 g of PE mol-1·Ni-1·h-1(at 5×105 Pa ethylene) were among the highest values using phenoxyiminato neutral nickel catalysts. Binuclear catalyst Ni3 showes better tolerance toward PPh3 donor additive than its mononuclear counterpart. In the presence of comonomers 1, 5-hexadiene, 1, 7-octadiene, 6-bromo-1-hexene, or methyl 10-undecenoate, these catalysts effectively enchain these comonomers into the polymer chain to give functionalized polyethylenes.
Mononuclear nickel complexes[(2, 6-R2-C6H3)NC(H)(3-Ph-5-PhCOO-2-O-C6H2)-κ2-N, O]Ni(CH3)(pyridine)](R=iPr; 3, 5-tBu2C6H3)(Ni1~Ni2) and binuclear nickel complex(Ni3) were synthesized, characterized and applied in ethylene (co)polymerization. As single-component catalysts, all these complexes are capable of converting ethylene to branched polyethylenes(PE) with moderate relative molecular mass. The electron-donating group PhCOO-facilitates the initiation of catalyst Ni1, leading to better catalytic activity at low temperature compared to nickel methyl pyridine comples(Ni0). Introducing bulky 2, 6-(3, 5-(t-Bu)2C6H3)2C6H3N-moiety, the activities of Ni2 up to 1.8×106 g of PE mol-1·Ni-1·h-1(at 5×105 Pa ethylene) were among the highest values using phenoxyiminato neutral nickel catalysts. Binuclear catalyst Ni3 showes better tolerance toward PPh3 donor additive than its mononuclear counterpart. In the presence of comonomers 1, 5-hexadiene, 1, 7-octadiene, 6-bromo-1-hexene, or methyl 10-undecenoate, these catalysts effectively enchain these comonomers into the polymer chain to give functionalized polyethylenes.
