Search

The construction and investigation of dual-functional coordination polymers (CPs) with proton conduction and luminescence sensing is of great significance in clean energy and agricultural monitoring fields. In this work, an Mn-based coordination polymer (Mn-CP), namely, [Mn0.5(HL)] (H2L = HOOCC6H4C6H4CH2PO(OH)OCH3), was hydrothermally synthesized. Mn-CP has a one-dimensional (1D) chain structure, in which uncoordinated –COOH groups can serve as potential sites for fluorescence sensing. Moreover, Mn-CP shows good water and pH stabilities, offering the feasibility for proton conduction and sensing applications. Mn-CP displays comparatively high proton conductivity of 1.07 × 10−4 S cm−1 at 368 K and 95% relative humidity (RH), which is promising for proton conduction materials. Moreover, it can serve as a repeatable, highly selective, and visualized fluorescence sensor for detecting oxytetracycline (OTC). More importantly, Mn-CP reveals an amazing quantitative sensing of OTC in actual samples such as seawater, aquaculture freshwater, soil infiltration solutions, and tap water. This work proves the excellent application potential of dual-functional CPs in the field of clean energy and environmental protection, especially for the fluorescence detection of antibiotics in aquaculture systems. [ABSTRACT FROM AUTHOR]

By selecting a bisphosphonic ligand H4L (H4L = 4-F-C6H4CH2N(CH2PO3H2)2) and a coligand oxalate (H2C2O4), three isostructural lanthanide metal–organic frameworks (Ln-MOFs) with a 2D layer structure, [Ln(H3L)(C2O4)]·2H2O (Ln = Eu (1), Gd (2), or Tb (3)), were hydrothermally prepared. By tuning the molar ratio of Eu3+, Gd3+, and Tb3+ in the above reactions, six bimetallic or trimetallic doped Ln-MOFs (EuxTb1−x (x = 0.02 (4), 0.04 (5), and 0.06 (6)), Gd0.94Eu0.06 (7), Gd0.96Tb0.04 (8) and Gd0.95Tb0.03Eu0.02 (9)) were obtained. The powder X-ray diffraction (PXRD) patterns of doped Ln-MOFs 4–9 show that they are isomorphous with 1–3. The bimetallic doped Ln-MOFs show a gradual variation of luminous colors between yellow-green, yellow, orange, pink, and light blue. Meanwhile, the trimetallic doped Gd0.95Tb0.03Eu0.02 Ln-MOF (9) displays near white-light emission with a quantum yield of 11.39%. Interestingly, the luminous inks of 1–9 are invisible and color tunable, which makes it possible to promote their anti-counterfeiting applications. Additionally, 3 displays good thermal, water, and pH stabilities, which provides the feasibility for its sensing application. The luminescence sensing experiments show that 3 can serve as a highly selective, reusable, and ratiometric luminescent sensor of sulfamethazine (SMZ). Moreover, 3 shows an excellent SMZ detection performance in real samples, such as mariculture water and real urine. Owing to the visible variation of the response signal under a UV lamp, portable SMZ test paper was prepared. [ABSTRACT FROM AUTHOR]

Developing high-accuracy luminescent sensors for detecting emerging environmental pollutants is of great importance and is still a challenge. Utilizing a 4-carboxyphenylphosphonic acid (H3pbc) ligand, a novel one-dimensional (1D) Zn-based coordination polymer with the formula [Zn2(Hpbc)2(2,2′-bipy)(H2O)]·H2O (Zn–CP, H3pbc = 4-HOOCC6H4PO3H2, 2,2′-bipy = 2,2′-bipyridine) has been hydrothermally synthesized. Each of the 1D chains was linked via π–π stacking interactions and formed a supramolecular framework. Furthermore, due to the existence of uncoordinated –COOH groups, the terbium-functionalized hybrid (Tb3+@Zn-CP) was prepared by introducing Tb3+ ions into the structure through coordinated postsynthetic modification (PSM). Tb3+@Zn-CP shows the characteristic emission of Tb3+ ions due to the "antenna effect" of the H3pbc ligand. Based on the excellent luminescence properties and structural stabilities of Zn-CP and Tb3+@Zn-CP, they can be used as highly sensitive and selective luminescent probes of the UV filter BP (benzophenone) depending on multiquenching effects. In addition, their obvious color change can be easily distinguished by the naked eye under ultraviolet light, which was successfully used in the preparation of portable BP test paper. More importantly, Tb3+@Zn-CP is the first example of CPs as a ratiometric luminescent sensor for BP. This work provides a novel strategy for the construction of ratiometric luminescent probes of BP-type UVFs through coordinated postsynthetic modification. [ABSTRACT FROM AUTHOR]

The development of a highly selective and sensitive optical method for quantitative enantioselective sensing of chiral amino acids in the presence of other amino acid interferences has remained a major challenge to date. Herein, a homochiral metal–organic framework (MOF), [Zn(L)(2,2′‐bipy)]·H2O (LNNU‐1) (H2L = HOOCC6H4CH2PO(OH)(OC2H5), 2,2′‐bipy = 2,2′‐bipyridine), is designed to interact with tryptophan via multiple noncovalent interactions. The interactions result in the emergence of a strong induced circular dichroism signal. This enables accurate determination of the absolute configuration and enantiomeric ratio of chiral tryptophan in water, mixed natural amino acids, and blood plasma components without any interference from other coexistent species. A simple device with advantageous characteristics of reusability and simple manipulation is designed for enantioselective sensing assay. The obtained results suggest that the rationally designed homochiral MOF is a promising candidate for enantioselective sensing of chiral species. [ABSTRACT FROM AUTHOR]

With the use of the tailored cyanometalate precursor, Bu4N[Fe(Tp*)(CN)3] (Tp* = hydridotris(3,5-dimethylpyrazol-1yl)borate), as the building block to react with fully solvated MII cations, three new one-dimensional (1D) heterobimetallic cyano-bridged chain complexes of squares, {[Fe(Tp*)(CN)3]2M (CH3CH2OH)2}·4H2O (M = Mn(1), Fe(2), Co(3)), have been prepared. In these compounds, the MII ions have slightly distorted octahedral coordination geometries, and they were bridged by [Fe(Tp*)(CN)3]− to form similar 1D chains of squares. The magnetic studies demonstrated that compound 1 exhibited weak ferromagnetism due to spin canting, compound 2 showed ferrimagnetic behavior in a low temperature region, whereas compound 3 indicated the presence of typical antiferromagnetic coupling. [ABSTRACT FROM AUTHOR]

A cyanide-bridged Fe Co double zigzag chain, {[Fe(bipy)(CN)]Co(btab)} [bipy=2,2′-bipyridine, btab=4,4′-(1,3-phenylene)-bis-4 H-1,2,4-triazole] ( 1), was obtained with tetracyanometalate precursors and Co ions. The chains were further linked by the ditopic btab ligands to a layer. Magnetic property studies demonstrate that 1 shows both metamagnetism with a critical field H =400 Oe and single-chain magnet behavior. [ABSTRACT FROM AUTHOR]

With the use of the tailored cyanometalate precursor, Bu4N[Fe(Tp*)(CN)3] (Tp* = hydridotris(3,5-dimethylpyrazol-1yl)borate), as the building block to react with fully solvated MII cations, three new one-dimensional (1D) heterobimetallic cyano-bridged chain complexes of squares, {[Fe(Tp*)(CN)3]2M (CH3CH2OH)2}·4H2O (M = Mn(1), Fe(2), Co(3)), have been prepared. In these compounds, the MII ions have slightly distorted octahedral coordination geometries, and they were bridged by [Fe(Tp*)(CN)3]− to form similar 1D chains of squares. The magnetic studies demonstrated that compound 1 exhibited weak ferromagnetism due to spin canting, compound 2 showed ferrimagnetic behavior in a low temperature region, whereas compound 3 indicated the presence of typical antiferromagnetic coupling. [ABSTRACT FROM AUTHOR]

Supercritical carbon dioxide (scCO 2) 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/TiO 2) catalytic reduction of nitro in scCO 2 instead of SnCl 2 /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 synthesis 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 scCO 2 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/TiO 2 catalyst in scCO 2 , 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 scCO 2 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. In this study, 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/TiO 2) catalytic reduction of nitro in scCO 2 , 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 synthesis 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 scCO 2 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.Synopsis: The synchronous synthesis and dyeing polyester fabrics of coumarin and 1,8-naphthalimide dyes in scCO 2 were also investigated. [Display omitted] • Three coumarin and 1,8-naphthalimide fluorescent dyes were constructed in scCO 2 media. • The synchronous synthesis and dyeing method was proposed for the synthesized dyes in scCO 2. • The constructing and dyeing strategy of fluorescent dyes is beneficial for the sustainable development of environment. [ABSTRACT FROM AUTHOR]

The investigation on the construction strategy, relationship between the structure and photophysical properties of fluorescein analogs plays an important role in the rational design of specific fluorescent dyes. In this work, a fluorescein analog Fc-1 , containing a reactive aldehyde group was prepared using 2′, 7′-dichlorofluorescein (DCF) as the raw material and Vilsmeier–Haack reaction mechanism. Meanwhile, two more fluorescein analogs Fc-2 and Fc-3 were synthesized based on Fc-1 and the Knoevenagel reaction mechanism. The results of Fc-1 indicated that the yield of Fc-1 was higher than 95% after a step of the low-temperature hydrolysis (40 °C) from an intermediate imine salt DCF-3. The fluorescence quantum yield (Φ) of Fc-1 was relatively high in polar protic solvents, even in H 2 O (Φ = 0.25). Fc-1 had large Stokes shifts in different solvents (≧ 123 nm), which was indentified by the Gaussian calculation of Fc-1. Meanwhile, Fc-1 was also used as a ratio and colorimetric fluorescent probe for H 2 S in vitro , and the dianion ([Fc-1-2H] 2- ) mechanism for detecting H 2 S was proposed by nuclear magnetic resonance (NMR), pH titration, and Gaussian calculation. Additionally, Fc-1 can be used in leukocyte classification because of its relatively high Φ in water, cell permeability, and cytotoxicity. All the data of dyes Fc-2 and Fc-3 indicated that the derivatization of the carboxyl group for Fc-2 did not affect the photophysical properties of Fc-2. Both of them had relatively large Stokes shifts and long emission wavelengths. The large Stokes shift of Fc-2 and Fc-3 was due to the distribution of electron clouds in the excited states of Fc-2 and Fc-3. The results of pH titration proved that dyes Fc-2 and Fc-3 were sensitive to the changes in pH and exhibited their potentials as pH probes. Thus, the strategy of constructing fluorescent dyes based on Vilsmeier–Haack and Knoevenagel reactions and the relationship between structure and properties will be beneficial to developing more dyes with large Stokes shift. In this work, three fluorescein analogs (Fc-1 , Fc-2 , and Fc-3) using DCF as raw material were designed and successfully synthesized by the Vilsmeier–Haack and Knoevenagel reaction mechanisms. Dye Fc-1 with reactive aldehyde group was obtained in high yield from the low-temperature hydrolysis. The photophysical results showed that Fc-1 had relatively high fluorescence quantum yields in polar proton solvents and large Stokes shifts in different solvents. The Gaussian calculation proved and explained the reason for the large Stokes shift of Fc-1. Meanwhile, it was found that Fc-1 could detect H 2 S in ratio and colorimetric assay. The mechanism of detecting H 2 S with Fc-1 was rationally proposed by combining the results of NMR, pH titrations, and Gaussian calculation. Additionally, Fc-1 realized the five-classification detection of leukocytes because of its good water solubility, cell permeability, and cytotoxicity. Further, the photophysical properties of dyes Fc-2 and Fc-3 were studied, which showed that both dyes exhibited large Stokes shifts and long emission wavelengths. The derivatization of the carboxyl group on the benzene ring did not affect the photophysical properties of Fc-2. Similarly, the Gaussian calculation method was used to explain the reason for the large Stokes shift. The spectral changes of two dyes at different pH values proved that dyes Fc-2 and Fc-3 had potential applications in pH fluorescent probes. The strategy of constructing fluorescent dyes with excellent photophysical properties was recommended on the basis of Vilsmeier–Haack and Knoevenagel reactions and it will be beneficial to developing more dyes. [Display omitted] • Three fluorescein analogs were constructed based on Vilsmeier-Haack and Knoevenagel condensation reactions. • The fluorescent dye Fc-1 can realize the detection of H 2 S and pH simultaneously. • The constructing strategy of fluorescent dyes based on Vilsmeier-Haack and Knoevenagel reactions will be beneficial to developing dyes with large Stokes shifts. Synopsis: Three fluorescein analogs with relatively good photophysical properties were synthesized and their relationships between structure and properties were investigated. [ABSTRACT FROM AUTHOR]

The construction and investigation of dual-functional coordination polymers (CPs) with proton conduction and luminescence sensing is of great significance in clean energy and agricultural monitoring fields. In this work, an Mn-based coordination polymer (Mn-CP), namely, [Mn 0.5 (HL)] (H 2 L = HOOCC 6 H 4 C 6 H 4 CH 2 PO(OH)OCH 3 ), was hydrothermally synthesized. Mn-CP has a one-dimensional (1D) chain structure, in which uncoordinated -COOH groups can serve as potential sites for fluorescence sensing. Moreover, Mn-CP shows good water and pH stabilities, offering the feasibility for proton conduction and sensing applications. Mn-CP displays comparatively high proton conductivity of 1.07 × 10 -4 S cm -1 at 368 K and 95% relative humidity (RH), which is promising for proton conduction materials. Moreover, it can serve as a repeatable, highly selective, and visualized fluorescence sensor for detecting oxytetracycline (OTC). More importantly, Mn-CP reveals an amazing quantitative sensing of OTC in actual samples such as seawater, aquaculture freshwater, soil infiltration solutions, and tap water. This work proves the excellent application potential of dual-functional CPs in the field of clean energy and environmental protection, especially for the fluorescence detection of antibiotics in aquaculture systems.

By selecting a bisphosphonic ligand H 4 L (H 4 L = 4-F-C 6 H 4 CH 2 N(CH 2 PO 3 H 2 ) 2 ) and a coligand oxalate (H 2 C 2 O 4 ), three isostructural lanthanide metal-organic frameworks (Ln-MOFs) with a 2D layer structure, [Ln(H 3 L)(C 2 O 4 )]·2H 2 O (Ln = Eu (1), Gd (2), or Tb (3)), were hydrothermally prepared. By tuning the molar ratio of Eu 3+ , Gd 3+ , and Tb 3+ in the above reactions, six bimetallic or trimetallic doped Ln-MOFs (Eu x Tb 1- x ( x = 0.02 (4), 0.04 (5), and 0.06 (6)), Gd 0.94 Eu 0.06 (7), Gd 0.96 Tb 0.04 (8) and Gd 0.95 Tb 0.03 Eu 0.02 (9)) were obtained. The powder X-ray diffraction (PXRD) patterns of doped Ln-MOFs 4-9 show that they are isomorphous with 1-3. The bimetallic doped Ln-MOFs show a gradual variation of luminous colors between yellow-green, yellow, orange, pink, and light blue. Meanwhile, the trimetallic doped Gd 0.95 Tb 0.03 Eu 0.02 Ln-MOF (9) displays near white-light emission with a quantum yield of 11.39%. Interestingly, the luminous inks of 1-9 are invisible and color tunable, which makes it possible to promote their anti-counterfeiting applications. Additionally, 3 displays good thermal, water, and pH stabilities, which provides the feasibility for its sensing application. The luminescence sensing experiments show that 3 can serve as a highly selective, reusable, and ratiometric luminescent sensor of sulfamethazine (SMZ). Moreover, 3 shows an excellent SMZ detection performance in real samples, such as mariculture water and real urine. Owing to the visible variation of the response signal under a UV lamp, portable SMZ test paper was prepared.

Developing high-accuracy luminescent sensors for detecting emerging environmental pollutants is of great importance and is still a challenge. Utilizing a 4-carboxyphenylphosphonic acid (H 3 pbc) ligand, a novel one-dimensional (1D) Zn-based coordination polymer with the formula [Zn 2 (Hpbc) 2 (2,2'-bipy)(H 2 O)]·H 2 O (Zn-CP, H 3 pbc = 4-HOOCC 6 H 4 PO 3 H 2 , 2,2'-bipy = 2,2'-bipyridine) has been hydrothermally synthesized. Each of the 1D chains was linked via π-π stacking interactions and formed a supramolecular framework. Furthermore, due to the existence of uncoordinated -COOH groups, the terbium-functionalized hybrid (Tb3+@Zn-CP) was prepared by introducing Tb 3+ ions into the structure through coordinated postsynthetic modification (PSM). Tb3+@Zn-CP shows the characteristic emission of Tb 3+ ions due to the "antenna effect" of the H 3 pbc ligand. Based on the excellent luminescence properties and structural stabilities of Zn-CP and Tb3+@Zn-CP, they can be used as highly sensitive and selective luminescent probes of the UV filter BP (benzophenone) depending on multiquenching effects. In addition, their obvious color change can be easily distinguished by the naked eye under ultraviolet light, which was successfully used in the preparation of portable BP test paper. More importantly, Tb3+@Zn-CP is the first example of CPs as a ratiometric luminescent sensor for BP. This work provides a novel strategy for the construction of ratiometric luminescent probes of BP-type UVFs through coordinated postsynthetic modification.

The preparation of single-chain magnets (SCMs) with photo-switchable bistable states is essential for the development of high-density photo-recording devices. However, the reversible switching of the SCM behavior upon light irradiation is a formidable challenge. Here we report a well-isolated double zigzag chain {[Fe(bpy)(CN) 4 ] 2 [Co(phpy) 2 ]}·2H 2 O (bpy = 2,2'-bipyridine, phpy = 4-phenylpyridine), which exhibits reversible redox reactions with interconversion between FeIIILS(μ-CN)CoIIHS(μ-NC)FeIIILS (LS = low-spin, HS = high-spin) and FeIIILS(μ-CN)CoIIILS(μ-NC)FeIILS linkages under alternating irradiation with 808 and 532 nm lasers. The bidirectional photo-induced metal-to-metal charge transfer results in significant changes of anisotropy and intrachain magnetic interactions, reversibly switching the SCM behavior. The on-switching SCM behavior driven by light irradiation at 808 nm could be reversibly switched off by irradiation at 532 nm. The results provide an additional and independent way to control the bistable states of SCMs by switching in the 0 → 1 → 0 sequence, with potential applications in high density storage and molecular switches.