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Reorientational dynamics of organic cations in perovskite-like coordination polymers
摘要： Here we report the dynamics of organic cations as guest molecules in a perovskite host-framework. The molecular motion of CH3NH3+ (MAFe), (CH3)2NH2+ (DMAFe) and (CH3)3NH+ (TrMAFe) in the cage formed by KFe(CN)63? units was studied using a combination of experimental methods: (i) thermal analysis, (ii) dielectric and electric studies, (iii) optical observations, (iv) EPR and 1H NMR spectroscopy and (v) quasielastic neutron scattering (QENS). In the case of MAFe and TrMAFe, the thermal analysis reveals one solid-to-solid phase transition (PT) and two PTs for the DMAFe crystal. A markedly temperature-dependent dielectric constant indicates the tunable and switchable properties of the complexes. Also, their semiconducting properties are confirmed by a dc conductivity measurement. The broadband dielectric relaxation is analyzed for the TrMAFe sample in the frequency range of 100 Hz–1 GHz. QENS shows that we deal rather with the localized motion of the cation than a diffusive one. Three models, which concern the simultaneous rotation of the CH3 and/or NH3 group, π-flips and free rotations of the organic cation, are used to fit the elastic incoherent structure factor. The 1H NMR spin–lattice relaxation time for all compounds under study, as well as the second moments, has been measured in a wide temperature range. In all studied samples, the temperature dependence of the second moment of the proton NMR line indicated the gradual evolution of the molecular movements from the rigid state up to a highly disordered one.
关键词： quasielastic neutron scattering,phase transitions,perovskite,coordination polymers,dielectric properties,NMR spectroscopy,dynamics,organic cations
更新于2025-11-14 17:28:48
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Synthesis, Crystal Structure and Fluorescent Properties of 1D New Double Chain Silver(I) Complex
摘要： A novel silver(I) complex [Ag(btzx)2(NO3)]n [complex 1, where btzx = m-xylylenebis(tetrazole)] is synthesized and characterized by elemental analysis, IR, powder and single crystal X-ray diffraction. The crystal structural analysis shows that silver center is four-coordinated in a distorted tetrahedral geometry by four nitrogen atoms from four different btzx and there are very weak interactions exist between Ag(I) and NO3– anions. This complex displays a 1D ladder-like double chain framework, which is further fabricated into a 2D supramolecular framework via π–π interactions. The fluorescence properties of complex 1 were investigated.
关键词： Silver complex,Coordination polymers,Flexible ligand,m-Xylylenebis(tetrazole)
更新于2025-11-14 14:48:53
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New one-dimensional mercury(II) coordination polymers built up from dispiro-dipyridyloxy-cyclotriphosphazene: Structural, thermal and UV-vis absorption properties
摘要： Reactions of flexible polydendate ligand system dispiro-dipyridyloxy-cyclotriphosphazene (L) with a variety of mercury(II) salts (HgX2) (X= I￣, Cl￣) afforded two one-dimensional mercury(II) coordination polymers, namely formulated as {[Hg(L)(I)2]}n (1) and {[Hg(L)(Cl)2]}n.(ACN)0,341 (2). The isolated crystalline compounds were structurally characterized by elemental analysis and single crystal X-ray crystallography. The X-ray crystal structure analysis revealed that 1 and 2 crystallizes in the orthorhombic (space group Pccn) and the monoclinic crystal system (space group P21/c), in which L exhibited a κ2N coordination binding mode with the divalent Hg ions to form one-dimensional chain structures. The central Hg2+ ion in 1 and 2 has a distorted tetrahedral coordination geometry. UV-Vis properties and thermal stability of L and complexes (1, 2) were also investigated. UV-Vis experiments (titration and continuous variation (Job’s plot) analysis) showed that all of spectrophotometric properties in solution state supports crystal structure of complexes. According to TGA analysis, coordination polymers exhibited thermal stability up to 300 °C, but L showed more thermal stability than 1 and 2.
关键词： JOBS Diagram,Pyridyloxy Cyclotriphosphazene,Hg2+ Coordination Polymers,UV-Vis Absorption,1D Coordination Polymers
更新于2025-09-23 15:23:52
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Structural diversity, magnetic properties, and luminescent sensing of four coordination polymers based on 6-(3,5-dicarboxylphenyl)nicotinic acid
摘要： Four coordination polymers (CPs), namely, [Ni(HDNA)(bibp)(H2O)]n (1), [Co(HDNA)(bibp)]n (2), {[Co(HDNA)(bibp)]·H2O}n (3) and {[Zn(HDNA)(bibp)]·H2O}n (4), have been synthesized from the mixed-ligand strategy of 6-(3,5-dicarboxylphenyl)nicotinic acid (H3DNA) and 4,4′-bis(benzimidazo-1-ly)benzene (bibp). Structural analyses revealed that four CPs all feature 2D sheets with diverse nets from {44.62}-sql net (1), {Co2(COO)2} SBUs based {44.62}-sql net (2), to 4-connected {65.8} sheet (3 & 4). Besides, the temperature-dependent magnetic susceptibilities of CPs 1-3 were investigated. And the luminescent sensing indicated CP 4 is a good bifunctional sensor for Fe3+ and Cr2O7 2- ions.
关键词： Structural diversity,Coordination polymers,Luminescent sensing,Magnetic property,Polycarboxylic acid ligand
更新于2025-09-23 15:23:52
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One-dimensional coordination polymers based on a new 3-position substituted imidazo[1,2-a]pyridine ligand: Crystal structures, photoluminescent and magnetic properties
摘要： A new 3-position substituted imidazo[1,2-a]pyridine ligand, namely, 5-(2-chloroimidazo[1,2-a]pyridine-3-carboxamido) isophthalic acid (H2L) was synthesized and characterized by 1H NMR spectroscopy. Based on this ligand, three isostructural one-dimensional coordination polymers, [ML(H2O)2]n (M = Zn (1), Ni (2) and Co (3)) were synthesized under the solvothermal conditions, and structurally characterized by single crystal X-ray diffraction, infrared spectroscopy, powder X-ray diffraction and elemental analyses. The coordination polymer 1 reveals similar photoluminescent spectrum to H2L ligand, but possesses the enhanced phosphorescent emission and higher phosphorescent quantum yield, compared to H2L ligand. Furthermore, the magnetic properties of coordination polymers 2 and 3 have been investigated, the results show there are antiferromagnetic interactions between the NiII ions or CoII ions in 2 or 3.
关键词： Photoluminescence,Coordination polymers,Imidazo[1,2-a]pyridine,X-ray structures,Magnetic properties
更新于2025-09-23 15:22:29
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Ratiometric Luminescent Sensor of Picric Acid based on the Dual-Emission Mixed-Lanthanide Coordination Polymer
摘要： Powerful explosive sensors play a key role in public security and environmental protection. Herein we report a series of isostructural lanthanide coordination polymers [Ln2L1.5(NMP)2]n (LnL, Ln = Eu , Gd, Tb, Dy, Ho and Er, H4L = [1,1′:4′,1″-terphenyl]-2′,4,4″,5′-tetracarboxylic acid, NMP = N-methyl-2-pyrrolidone) and mixed-Ln LnL (EuxTb1-xL, EuxGd1-xL, TbxGd1-xL and EuxTb0.02-xGd0.98L). Luminescence studies show that both H4L and GdL emit strong fluorescence and phosphorescence at 77 K while only fluorescence at room temperature, and TbL exhibits strong Tb3+ characteristic emission though the energy difference between the triplet excited state of H4L (20661 cm-1) and the 5D4 energy level of Tb3+ (20500 cm-1) is very small. By doping Eu3+ and Tb3+ into GdL, we obtained EuxTb0.02-xGd0.98L emitting warm white light. For TbL and Tb0.01Gd0.99L showing the dual-emission, upon addition of picric acid (PA) into their suspensions in Tris-HCl buffer, Tb3+ emission decreases slowly, however, the ligand-based emission is sharply quenched, rendering TbL and Tb0.01Gd0.99L excellent single-lanthanide and mixed-lanthanide ratiometric luminescence PA sensor materials, respectively.
关键词： picric acid (PA),ratiometric luminescence sensors,white light emission,metal-organic frameworks (MOFs),Coordination polymers (CPs)
更新于2025-09-23 15:21:21
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Synthesis of eight isostructural 2D lanthanide coordination polymers assembled by rigid furan-2,5-dicarboxylic acid and flexible adipic acid as linkers and exploration of luminescent Eu/Tb polymers as efficient and sensitive sensors for nitroaromatic compounds
摘要： Detection of hazardous chemicals is crucial for a healthy and safe environment as well as for the well-being of humans. A confluence of chemistry and engineering continues to improve the sensitivity and selectivity for several classes of harmful chemicals with the promise of cheap and portable sensing. Herein, following the function-oriented research strategy, eight novel lanthanide coordination polymers (Ln-CPs) have been successfully assembled with the framework composition [Ln(2,5-FDC)0.5(Adip)(H2O)2] (Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), Ho (7), Er (8), 2,5-FDC2? = furan-2,5-dicarboxylate, Adip2? = Adipate) under solvothermal synthesis conditions. The structural analysis indicates that all the eight CPs have the same structural features. All compounds crystallize in the orthorhombic crystal system (space group Pnma) with point symbol {33·44·53} and consist of 2D cem topological type. The linkers 2,5-FDC2? and Adip2? exhibit μ2-κ4,Z1:Z1:Z1:Z1 and μ3-κ5,Z2:Z1:Z1:Z1 coordination modes respectively. The as-synthesized polymers were characterized by powder X-ray crystallography, infrared spectroscopy, thermogravimetric analysis, and photoluminescence studies. CP-3 and CP-5 are promising luminescent lanthanide coordination polymers (Ln-CPs) and function as efficient sensors for the detection of nitroaromatic compounds at the ppm level in mix N,N′-dimethyl formamide-aqueous medium via the luminescence quenching mechanism.
关键词： furan-2,5-dicarboxylic acid,lanthanide coordination polymers,adipic acid,luminescent sensors,nitroaromatic compounds
更新于2025-09-23 15:21:01
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Heterometallic Cluster Coordination Polymers Assembled from Cuprous-Halide Clusters and Organotina??Oxygen Pyridinecarboxylate Clusters
摘要： By using the bifunctional ligands bearing carboxylate and N-donor groups, the precursor of nBu2SnO undergoes a transformation to yield organotin–oxygen carboxylate clusters, namely, [(nBu2Sn)4(μ3-O)2(μ2-OH)2(INA)2] (INA = isonicotinate), [(nBu2Sn)5(μ3-O)3(μ2-OH)2(INA)2] and [(nBu2Sn)4(μ3-O)2(NA)4] (NA = nicotinate), resulting in different geometric building units with two or four extension points. Such organotin–oxygen carboxylate clusters assemble with various CunIn clusters such as Cu2I2 rhomboid dimer, Cu4I4 cubic tetramer, Cu6I6 prismatic hexamer to engender various heterometallic cluster coordination polymers.
关键词： organotin–oxygen pyridinecarboxylate clusters,heterometallic cluster coordination polymers,bifunctional ligands,structural dimensions,cuprous-halide clusters
更新于2025-09-23 15:19:57
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Coupled Electrical Conduction in Coordination Polymers: From Electrons/Ions to Mixed Charge Carriers
摘要： The coupled transport of ions and electrons is of great potential for next-generation sensors, energy storage and conversion devices, optoelectronics, etc. Coordination polymers (CPs) intrinsically have both transport pathways for electrons and ions, however, the practical conductivities are usually low. In recent years, significant advances have been made in electronic or ionic conductive coordination polymers, which also results in progress in mixed ionic-electronic conductive coordination polymers. Here we start from electronic and ionic conductive CPs to mixed ionic-electronic conductive CPs. Recent advances in the design of mixed ionic-electronic conductive CPs are summarized. In addition, devices based on mixed conduction are selected.
关键词： metal-organic frameworks,coordination polymers,ionic,conductivity,electronic
更新于2025-09-23 15:19:57
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Solvent-controlled assembly of two Zn(II) coordination polymers constructed from 1,3,5-tris(1-imidazolyl)benzene and 2,5-dichloroterephthalic acid with fluorescent recognition of carcinogenic dye in chloroform
摘要： Two Zn(II) coordination polymers, [Zn2(tib)2(BDC-Cl2)(HBDC-Cl2)2](cid:1)2H2O (1) and [Zn(tib)(BDC-Cl2)](cid:1)H2O (2), were synthesized by reaction of 1,3,5-tris(1-imidazolyl)benzene (tib) and 2,5-dichloroterephthalic acid (H2BDC-Cl2) with Zn2t under solvothermal conditions. The results of X-ray single-crystal analysis show that 1 possesses a 1-D chain structure, while 2 exhibits a 2-D layer structure with {44(cid:1)62} topology. Both display a 3-D supramolecular framework through hydrogen bonding interactions. Experimental results indicated that the ratio of solvent may regulate the structural formation of the polymers. 1 and 2 were further characterized by powder X-ray diffraction (PXRD), IR spectroscopy, thermogravimetric analysis (TGA), and elemental analysis. Notably, 1 and 2 possess the ability to identify chloroform by emitting specific fluorescence spectra. Both can detect carcinogens in dyes by the modified fluorescent signal of the compound in chloroform.
关键词： crystal structure analysis,mixed-ligand strategy,carcinogen identification,Zinc(II)-coordination polymers,fluorescent recognition
更新于2025-09-23 15:19:57