Designing Multifunctional 5-Cyanoisophthalate-Based Coordination Polymers as Single-Molecule Magnets, Adsorbents, and Luminescent Materials

Two coordination polymers: Crystal structures, prevention and nursing values on postoperative infection

In this current work, two fresh transition metal coordination polymers (CPs) have been created with the reaction between terphenyl-3,3″,5,5″-tetracarboxylic acid (H4L), the symmetrical rigid carboxylic acid ligand and the relevant metal salts under the reaction conditions of solvothermal, and the chemical compositions of the compounds respectively are {[Cu2(TPTC) (DMF)2(H2O)]·2DMF·2H2O} (2) and {[Zn (TPTC) (1,2-bimb)2]·4(H2O)}n (1, bimb = 1,2-bis((1H-imidazol-1-yl)methyl)benzene). Moreover, the prevention and nursing values of the compound on postoperative infection was explored and their corresponding mechanism also was investigated. Firstly, enzyme linked immunosorbent assay kit (ELISA) was employed to detect the release of inflammatory cytokines into plasma. Additionally, the expression of the bacterial survival genes was determined via exploiting the real time reverse transcription-polymerase chain reaction (RT-PCR) after treated with the compound.

Two Transition Metal Coordination Polymers: Luminescent Sensing Properties and Treatment Effect on Chronic Periodontitis by Reducing IL-6 and TNF-α Content

Two novel sulfonic functionalized coordination polymers (CPs) {[Cd1.5(dimb)(5-sip)(H2O)3]·3H2O}n (1, dimb = 1,4-di(1H-imidazol-1-yl)butane) and [Co2(iptz)(Hiptz)(5-sip)(H2O)]·4H2O (2, Hiptz = 1-(4-(1H-imidazole-5-yl)phenyl)-1H-1,2,4-triazole) were acquired via different metal(II) salts reacting with the mixed ligands containing 1-(4-(1H-imidazole-5-yl)phenyl)-1H-1,2,4-triazole, 1,4-di(1H-imidazol-1-yl)butane and sodium 5-sulfoisophthalate (NaH2sip), respectively. Furthermore, the complex 1 based on Cd(II) could be utilized as the luminescent senor for picric acid (PA) detection in water. In bio-research, compounds 1 and 2 treatment effect on chronic periodontitis was assessed and the specific mechanism was discussed. First of all, the RT-PCR was performed to measure the HmuY and fimA genes relative expression level in P.gingivalis after treated by compounds 1 and 2. Then, the TNF-α and IL-6 content in the fluid of gingival crevicular after compounds treatment was determined with ELISA detection kit.

Modulating Magnetic and Photoluminescence Properties in 2-Aminonicotinate-Based Bifunctional Coordination Polymers by Merging 3d Metal Ions

Herein, the synthesis and study of bifunctional coordination polymers (CPs) with both magnetic and photoluminescence properties, derived from a heterometallic environment, are reported. As a starting point, three isostructural monometallic CPs with the formula [M(μ-2ani)₂ ]_n (M^II =Mn (1_Mn ), Co (3_Co ) and Ni (4_Ni ); 2ani=2-aminonicotinate), crystallise as chiral 2D-layered structures stacked by means of supramolecular interactions. These compounds show high thermal stability in the solid state (above 350 °C), despite which, in aqueous solution, compound 1_Mn is shown to partially transform into a novel 1D chain CP with the formula [Mn(2ani)₂ (μ-H₂ O)₂ ]_n (2_Mn ). A study of the direct current (dc) magnetic properties of 1_Mn , 3_Co and 4_Ni reveals a spin-canted structure derived from antisymmetric antiferromagnetic weak exchanges along the chiral network (as confirmed by DFT calculations) and magnetic anisotropy of the ions, in such a way that long-range ordering is observed with variable magnitude for the spin carriers. Moreover, compounds 3_Co and 4_Ni show no frequency-dependent alternating current (ac) susceptibility curves under zero dc field; this is characteristic behaviour of a glassy state that may be partially supressed for 3_Co by applying an external dc field. To overcome long-range magnetic ordering, Co^II ions are diluted in a diamagnetic Zn^II -based matrix, which enables single-molecule magnet behaviour. Interestingly, this strategy allows a bifunctional Co_x Zn_1-x 2ani material, which is imbued with a strong photoluminescent emitting capacity, as characterised by an intense blue light followed by a green afterglow, to be obtained.

Magnetic and Photoluminescent Sensors Based on Metal-Organic Frameworks Built up from 2-aminoisonicotinate

In this work, three isostructural metal-organic frameworks based on first row transition metal ions and 2-aminoisonicotinate (2ain) ligands, namely, {[M(μ-2ain)₂]·DMF}_n [M^II = Co (1), Ni (2), Zn (3)], are evaluated for their sensing capacity of various solvents and metal ions by monitoring the modulation of their magnetic and photoluminescence properties. The crystal structure consists of an open diamond-like topological 3D framework that leaves huge voids, which allows crystallizing two-fold interpenetrated architecture that still retains large porosity. Magnetic measurements performed on 1 reveal the occurrence of field-induced spin-glass behaviour characterized by a frequency-independent relaxation. Solvent-exchange experiments lead successfully to the replacement of lattice molecules by DMSO and MeOH, which, on its part, show dominating SIM behaviour with low blocking temperatures but substantially high energy barriers for the reversal of the magnetization. Photoluminescence studied at variable temperature on compound 3 show its capacity to provide bright blue emission under UV excitation, which proceeds through a ligand-centred charge transfer mechanism as confirmed by time-dependent DFT calculations. Turn-off and/or shift of the emission is observed for suspensions of 3 in different solvents and aqueous solutions containing metal ions.

Three chiral one-dimensional lanthanide–ditoluoyl-tartrate bifunctional polymers exhibiting luminescence and magnetic behaviors

Since Ln-CPs have excellent optical properties (higher color purity, longer fluorescence lifetime and higher quantum yield) and magnetic properties, it is of great significance to prepare dual magneto-optical materials based on Ln(iii). Herein, we obtained three versatile Ln-CPs, [Ln(HDTTA)₃(CH₃OH)₃]_n, derived from reactions of lanthanide salts (Ln = Tb 1, Dy 2, Ho 3) and a chiral and flexible ligand, namely, (+)-di-p-toluoyl-d-tartaric acid (d-H₂DTTA) in a methanol–water solution, at room temperature and pressure. The structures of these compounds have been characterized by single crystal and powder X-ray diffraction, infrared spectroscopy, elemental analyses and thermogravimetric analyses. Complexes 1–3 are isomorphic, crystallizing in the chiral trigonal R3 space group with the linkage of Ln³⁺ ions and featuring 1D propeller chain structures. The circular dichroism spectra confirm that the complexes maintain the chirality from the ligands. Furthermore, the luminescent and magnetic properties have been investigated, relying on intrinsic properties of the lanthanide ions. The photoluminescence measurements indicate that 1, 2 and 3 show strong green, white and blue emission bands with CIE chromaticity coordinates of (0.32, 0.56), (0.29, 0.26) and (0.21, 0.12), respectively. The decay lifetime curve of 1 shows the exponential decay with long lifetime of 1.169 ms and the relative quantum yield for 1 was 19.31%. In addition, the magnetic properties of complexes 1–3 have been investigated by measuring the magnetic susceptibility in the temperature range of 2–300 K. They are all dominated by spin–orbit coupling and ligand field perturbation, and the exchange coupling between Ln³⁺ ions is almost negligible. Therefore, complexes 1–3 are promising chiral, optical and magnetic multifunctional materials.

Self-assembly of three chiral one-dimensional Ln-CPs with luminescence and magnetic behaviors.

Effect of the change of the ancillary carboxylate bridging ligand on the SMM and luminescence properties of a series of carboxylate-diphenoxido triply bridged dinuclear ZnLn and tetranuclear Zn2Ln2 complexes (Ln = Dy, Er)

Eleven new dinuclear and tetranuclear compounds of general formulae [Zn(μ-L)(μ-X)Ln(NO3)2]·nS, [Zn2Dy2(μ3-L')2(μ-sal)2(NO3)(CH3OH)](NO3)·5CH3OH and [Zn2Er2(μ3-L')2(μ-sal)2(CH3OH)2](NO3)2·4CH3OH (X = benzoate, anthracenate, diclofenac, salicylate, 2,6-dihydroxybenzoate; Ln = Dy, Er; S = water, acetonitrile, methanol) were prepared from the N,N'-dimethyl-N,N'-bis(2-hydroxy-3-formyl-5-bromobenzyl)ethylenediamine compartmental ligand (H2L). Complexes 1-6 and 9-11 consist of diphenoxido-carboxylate triply bridged compounds, which differ mainly in the carboxylate bridging ligand. It should be noted that the acidic character of the salicylic acid promotes, in the presence of methanol, the methoxylation of the H2L ligand thereby yielding a hemiacetal H3L', which is able to connect the Ln(iii) ions of two ZnLn dinuclear units forming the Zn2Ln2 tetranuclear complexes 7 and 8. All compounds display SMM behaviour in the presence of an external field with effective energy barriers (Ueff) as high as 61 K. Magneto-structural data for these complexes reveal that their SMM behaviour is not only significantly affected by the type of Ln(iii) ion but also by the carboxylate bridging ligand connecting the Zn(ii) and Ln(iii) ions. Photoluminescence properties have also been accomplished, showing that the ligands are able to sensitize lanthanide centred emissions in the visible and near-infrared regions with variable capacity. Moreover, the analysis of the luminescence decay curves reveals emission lifetimes in the range of few microsecond or hundreds of nanoseconds for Dy(iii)-based or Er(iii)-based luminophores, respectively.

Magnetic and luminescent coordination networks based on imidazolium salts and lanthanides for sensitive ratiometric thermometry

The synthesis and characterization of six new lanthanide networks [Ln(L)(ox)(H₂O)] with Ln = Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺, Ho³⁺ and Yb³⁺ is reported. They were synthesized by solvo-ionothermal reaction of lanthanide nitrate Ln(NO₃)₃·xH₂O with the 1,3-bis(carboxymethyl)imidazolium [HL] ligand and oxalic acid (H₂ox) in a water/ethanol solution. The crystal structure of these compounds has been solved on single crystals and the magnetic and luminescent properties have been investigated relying on intrinsic properties of the lanthanide ions. The synthetic strategy has been extended to mixed lanthanide networks leading to four isostructural networks of formula [Tb_{1- x} Eu _x (L)(ox)(H₂O)] with x = 0.01, 0.03, 0.05 and 0.10. These materials were assessed as luminescent ratiometric thermometers based on the emission intensities of ligand, Tb³⁺ and Eu³⁺. The best sensitivities were obtained using the ratio between the emission intensities of Eu³⁺ (⁵D₀→⁷F₂ transition) and of the ligand as the thermometric parameter. [Tb_0.97Eu_0.03(L)(ox)(H₂O)] was found to be one of the best thermometers among lanthanide-bearing coordination polymers and metal-organic frameworks, operative in the physiological range with a maximum sensitivity of 1.38%·K^-1 at 340 K.

Design and synthesis of a family of 1D-lanthanide-coordination polymers showing luminescence and slow relaxation of the magnetization

We have designed and synthesized eight isostructural 1D coordination polymers (CPs) with the general formula {[Ln(aapc)3(DMF)]}n [where Ln(iii) = Y (2), La (3), Nd (4), Eu (5), Gd (6), Tb (7), Dy (8), Er (9); and aapc = 3-((anthraquinone-1-yl)amino)propanoate]. These CPs consist of Ln-carboxylate infinite rods in which the bulky anthraquinone scaffolds arise from it in such a way that the resulting supramolecular packing exhibits isolated 1D chains. Solution structures have been corroborated through NMR methods including PGSE and EXSY NMR studies and, due to the presence of lanthanide ions, magnetic and luminescence properties have been studied. Alternating current magnetic measurements of compound 8 show slow relaxation of the magnetization, a characteristic of single molecule magnets (SMMs). The evaluation of solid-state photophysical properties reveals that the aapc scaffold sensitizes lanthanide(iii) based emission of compounds 4-9 both in the visible and near-infrared (NIR) regions at 10 K.

3D LnIII-MOFs: slow magnetic relaxation and highly sensitive luminescence detection of Fe3+ and ketones

Five Ln-MOFs were obtained: the Dy-MOF shows slow magnetic relaxation, and the Eu-MOF and Tb-MOF show selective and sensitive sensing towards Fe³⁺ ions and ketones in a water system.

Slow relaxation of magnetization and luminescence properties of a novel dysprosium and pyrene-1,3,6,8-tetrasulfonate based MOF

A novel multifunctional Dy(iii) and pyrene-1,3,6,8-tetrasulfonate based MOF displays intense PL/ SIM behaviour.