Mixture Of Ligands Research Articles

Ligand-Dependent Coalescence Behaviors of Gold Nanoparticles Studied by Multichamber Graphene Liquid Cell Transmission Electron Microscopy.

The formation mechanism of colloidal nanoparticles is complex because significant nonclassical pathways coexist with the conventional nucleation and growth processes. Particularly, the coalescence of the growing clusters determines the final morphology and crystallinity of the synthesized nanoparticles. However, the experimental investigation of the coalescence mechanism is a challenge because the process is highly kinetic and correlates with surface ligands that dynamically modify the surface energy and the interparticle interactions of nanoparticles. Here, we employ quantitative in situ TEM with multichamber graphene liquid cell to observe the coalescence processes occurring in the synthesis of gold nanoparticles in different ligand systems, thus affording us an insight into their ligand-dependent coalescence kinetics. The analyses of numerous liquid-phase TEM trajectories of the coalescence and MD simulations of the ligand shells demonstrate that enhanced ligand mobility, employing a heterogeneous ligand mixture, results in the rapid nanoparticle pairing approach and a fast post-merging structural relaxation.

Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)-dipicolylamine complexes.

Gold nanoparticles covered with a mixture of ligands of which one type contains solubilizing triethylene glycol residues and the other peripheral zinc(II)–dipicolylamine (DPA) complexes allowed the optical detection of hydrogenphosphate, diphosphate, and triphosphate anions in water/methanol 1:2 (v/v). These anions caused the bright red solutions of the nanoparticles to change their color because of nanoparticle aggregation followed by precipitation, whereas halides or oxoanions such as sulfate, nitrate, or carbonate produced no effect. The sensitivity of phosphate sensing depended on the nature of the anion, with diphosphate and triphosphate inducing visual changes at significantly lower concentrations than hydrogenphosphate. In addition, the sensing sensitivity was also affected by the ratio of the ligands on the nanoparticle surface, decreasing as the number of immobilized zinc(II)–dipicolylamine groups increased. A nanoparticle containing a 9:1 ratio of the solubilizing and the anion-binding ligand showed a color change at diphosphate and triphosphate concentrations as low as 10 μmol/L, for example, and precipitated at slightly higher concentrations. Hydrogenphosphate induced a nanoparticle precipitation only at a concentration of ca. 400 μmol/L, at which the precipitates formed in the presence of diphosphates and triphosphates redissolved. A nanoparticle containing fewer binding sites was more sensitive, while increasing the relative number of zinc(II)–dipicolylamine complexes beyond 25% had a negative impact on the limit of detection and the optical response. Transmission electron microscopy provided evidence that the changes of the nanoparticle properties observed in the presence of the phosphates were due to a nanoparticle crosslinking, consistent with the preferred binding mode of zinc(II)–dipicolylamine complexes with phosphate anions which involves binding of the anion between two metal centers. This work thus provided information on how the behavior of mixed monolayer-protected gold nanoparticles is affected by multivalent interactions, at the same time introducing a method to assess whether certain biologically relevant anions are present in an aqueous solution within a specific concentration range.

Characterization of the unimodality constraint as an effective chemistry-based condition in resolving of chemical processes data

Multivariate curve resolution (MCR) techniques are powerful methods for qualitative and quantitative analyses of spectral data. However, MCR methods suffer from non-unique solutions - instead of a unique solution usually a continuum of possible pure component decomposition exists. This ambiguity is covered in a low-dimensional way by the so-called area feasible solutions (AFS). In the quantitative purpose, the rotational ambiguity has a negative effect on the accuracy of the results. By applying additional constraints on the profiles the range of feasible solutions can considerably improve the reliability of quantitative results. Another approach to analyze the size of the continuum of possible pure component profiles is to compute the extrema of the signal contribution function (SCF). The SCF can also be applied under additional constraints.In this study we analyze the restriction of the AFS and the change of the SCF-extrema under additional unimodality constraints. An interesting effect is stated for two examples namely that the unimodality constraint can divide a single subset of the AFS into two parts. In such cases the SCF cannot resolve the ambiguity completely. The effect of the unimodality constraints has been systematically investigated on two- and three-component simulation data sets. This phenomenon are also studied for an experimental data set related to the spectrophotometric titration of a mixture of ligand (3,7-diazanonanedioic acid diamide) and Cu2+ with varying degrees of acidity. Imposing of unimodality constraints as an effective chemically meaningful limitation on the feasible solutions of MCR methods is strongly recommended.

Polarized perovskite luminescence

Nanomaterials Optical elements can generate circularly polarized luminescence (CPL), but sources that directly emit CPL are desirable for many applications. Kim et al. synthesized formamidinium lead bromide nanocrystals (NCs) with mixtures of longer achiral ligands and shorter chiral ( R )-2-octylamine. Lower fractions of the chiral ligand formed smaller NCs that had stronger CPL at room temperature, apparently because these NCs have a higher fraction of chiral ligands that also have stronger electronic interactions with their perovskite cores. The perovskite NCs exhibited a luminescence dissymmetry g-factor of ∼0.06 at wavelengths between 520 and 540 nanometers. Although purification steps removed some of the chiral ligand, CPL could be restored in thin films with the addition of ( R )- or ( S )-methylbenzylammonium bromide. ACS Nano 14 , 8816 (2020).

Enhanced extracellular electron transfer of yeast-based microbial fuel cells via one pot substrate-bound growth iron-manganese oxide nanoflowers

The growth of manganese oxide decorated iron oxide nanoflowers atop polyethylenimine functionalized carbon felt via surface-bound iron particle seeds is explored with and without the aid of a surfactant ligand in a one-pot aqueous solution for the first time. Widespread, uniquely shaped, rough nanocrystal growth is shown to develop on the hydrophilic surface of functionalized carbon felt fibers and the growth is achieved using a seed, initiator, reducer, and ligand mixture. The structure of the iron-manganese oxide nanoflowers are optically examined, and the anodic viability of the modified carbon felt in microbial fuel cells is determined through analysis of the stimulation and maturation of yeast via electrochemical characterization. The developmental growth of the iron-manganese oxide nanoparticles with the beneficial addition of the surfactant ligand, sodium dodecylbenzenesulfonate, and different ratios of iron to manganese are observed to have an effect on the condition of yeast biofilm inhabitancy, viability, and the resulting electrochemical behaviour. The best power density of 5.8 ± 0.61 W m−2 is achieved when utilizing this surfactant mediated iron-manganese oxide nanoparticle growth technique to the microbial fuel cell anode.

LM-ANN-based QSAR model for the prediction of pEC50 for a set of potent NNRTI using the mixture of ligand–receptor interaction information and drug-like indexes

A combination of ligand–receptor interactions and drug-like indexes have been used to develop a quantitative structure–activity relationship model to predict anti-HIV activity (pEC50) of 73 azine derivatives as non-nucleoside reverse transcriptase inhibitors. Ligand–receptor interactions were derived from the best position (best pose) of studied compounds, as ligands, in the active site of receptors using Autodock 4.2 software and named as molecular docking descriptors. The drug-like indexes were calculated using DRAGON 5.5 software. Two groups of descriptors were mixed, and the stepwise regression method was used for the selection of the most relevant descriptors. Four selected descriptors were subsequently used to construct the quantitative structure–activity relationship model using the Levenberg–Marquardt artificial neural network method. Dataset was randomly divided into the train (53 compounds), validation (10 compounds) and test set (10 compounds). The best model was selected according to the lowest mean square error value of the validation set. The accuracy and predictability of the model were evaluated using test and validation sets and the leave-one-out technique. According to the predicted results, the coefficient of determination of the test set (R2 = 0.86) and all data ( $${Q}_{LOO}^{2}$$ = 0.73) were acceptable. The mean square error value for the test set was equal to 0.11. The obtained results emphasized the good prediction ability and generalizability of the developed model in the prediction of pEC50 values for new compounds.

Predicting the Activation of the Androgen Receptor by Mixtures of Ligands Using Generalized Concentration Addition.

Concentration/dose addition is widely used for compounds that act by similar mechanisms. But it cannot make predictions for mixtures of full and partial agonists for effect levels above that of the least efficacious component. As partial agonists are common, we developed generalized concentration addition, which has been successfully applied to systems in which ligands compete for a single binding site. Here, we applied a pharmacodynamic model for a homodimer receptor system with 2 binding sites, the androgen receptor, that acts according to the classic homodimer activation model: Each cytoplasmic monomer protein binds ligand, undergoes a conformational change that relieves inhibition of dimerization, and binds to DNA response elements as a dimer. We generated individual dose-response data for full (dihydroxytestosterone, BMS564929) and partial (TFM-4AS-1) agonists and a competitive antagonist (MDV3100) using reporter data generated in the MDA-kb2 cell line. We used the Schild method to estimate the binding affinity of MDV3100. Data for individual compounds fit the homodimer pharmacodynamic model well. In the presence of a full agonist, the partial agonist had agonistic effects at low effect levels and antagonistic effects at high levels, as predicted by pharmacological theory. The generalized concentration addition model fits the empirical mixtures data-full/full agonist, full/partial agonist, and full agonist/antagonist-as well or better than relative potency factors or effect summation. The ability of generalized concentration addition to predict the activity of mixtures of different types of androgen receptor ligands is important as a number of environmental compounds act as partial androgen receptor agonists or antagonists.

Theoretical Characterization of Catalytically Active Species in Reductive Hydroxymethylation of Styrene with CO2 over a Bisphosphine-Ligated Copper Complex.

In this work, a density functional theory (DFT) study was performed to identify the catalytically active species in the copper-catalyzed three-component reductive hydroxymethylation of styrene with CO2 and hydrosilane. The calculations reveal that the dimeric copper(I) hydride species, formed in a mixture of the bisphosphine ligand, Cu(OAc)2, and hydrosilane, probably acts as the catalyst precursor. In the beginning, this species is catalytically competent to trigger the hydrocupration of styrene, along with the formation of the dimeric copper(I) alkyl intermediate. Subsequently, CO2 insertion into the dimeric copper(I) alkyl intermediate occurs, which is accompanied by the cleavage of the Cu-Cu bond and the generation of the monomeric copper(I) carboxylate intermediate. In the end, the sequential reduction of the monomeric copper(I) carboxylate intermediate with the hydrosilane produces the monomeric copper(I) hydride species as the actual catalyst and turns on the catalytic cycle. On the other hand, the monomeric copper(II) hydride species, yielded as the kinetic product in the initial reaction of the bisphosphine ligand, Cu(OAc)2, and hydrosilane, is also reactive for the hydrocupration of styrene. However, the resulting monomeric copper(II) alkyl intermediate is found to be the catalyst resting state, because of the much higher energy barrier demanded for the subsequent nucleophilic attack toward CO2. On the basis of the results of an activation-strain model (ASM) analysis and charge decomposition analysis (CDA), the low activity of the monomeric copper(II) alkyl intermediate can be ascribed to the more crowded environment around the central copper(II) ion and the weaker nucleophilicity of the alkyl moiety. Furthermore, all of the possible CuH species generated in the system are competent to promote the two-component hydrosilylation of CO2 with hydrosilane, which is an inevitable side reaction along with the reductive hydroxymethylation of styrene with CO2 and hydrosilane.

Experimental, Structural, and Computational Investigation of Mixed Metal–Organic Frameworks from Regioisomeric Ligands for Porosity Control

Porosity control and structural analysis of metal–organic frameworks (MOFs) can be achieved using regioisomeric ligand mixtures. While ortho-dimethoxy-functionalized MOFs yielded highly porous structures and para-dimethoxy-functionalized MOFs displayed almost nonporous properties in their N2 isotherms after evacuation, regioisomeric ligand-mixed MOFs showed variable N2 uptake amount and surface area depending on the ligand-mixing ratio. The quantity of N2 absorbed was tuned between 20 and 300 cm3/g by adjusting the ligand-mixing ratio. Both experimental analysis and computational modeling were performed to understand the porosity differences between ortho- and para-dimethoxy-functionalized MOFs. Detailed structural analysis using X-ray crystallographic data revealed significant differences in the coordination environments of DMOF-[2,3-(OMe)2] and DMOF-[2,5-(OMe)2] (DMOF = dabco MOF, dabco = 1,4-diazabicyclo[2.2.0]­octane). The coordination bond between Zn2+ and carboxylate in the ortho-functionalized DMOF-[2,3-(OMe)2] was more rigid than that in the para-functionalized DMOF-[2,5-(OMe)2]. Quantum-chemical simulation also showed differences in the coordination environments of Zn secondary building unit surrounded by methoxy-functionalized ligands and pillar ligands. In addition, the binding energy differences between Zn2+ and regioisomeric ligands (ortho- and para-dimethoxy-functionalized benzene-1,4-dicarboxylates) explained the rigidity and porosity changes of the mixed MOFs upon evacuation and perfectly matched with experimental N2 adsorption and X-ray crystallography data.

Interaction of pyridoxal-derived hydrazones with anions and Co2+, Co3+, Ni2+, Zn2+ cations

ABSTRACT Present paper reports on the interactions between four hydrazones derived from pyridoxal and hydrazides of 2-furoic, thiophene-2-carboxylic, pyrazinoic and pyridine-3-carboxylic acids and 10 different anions (F−, Cl−, I−, PO4 3-, HPO4 2-, H2PO4 3-, NO3 −, SO3 2-, SO4 2-, CH3COO−) and three cations (Co2+, Ni2+, Zn2+). Hydrazones are sensitive towards anion presence in non-buffered DMSO only, thus, indicating that the proton transfer from ligand towards anion is responsible for the changes in colour, UV-Vis and fluorescent spectra. Buffered solutions of ligand mixture with any anion are indistinguishable from free hydrazone. The addition of d-metal ions to pyridoxal-derived hydrazones dissolved in buffered DMSO changes the solution colour, UV-Vis and fluorescent spectra. Conditional rate constants of Co2+ oxidation, as well as the apparent stability constants of Co2+, Co3+ complexes with Schiff bases, were determined from kinetic experiments, while Ni2+, Zn2+ complexes stability constants were calculated from UV-Vis and fluorimetry titration data.

Double-Propeller-like Heterometallic 3d-4f Clusters Ln18Co7.

Two high-nuclearity lanthanide-transition metal clusters with the general formula [Ln18CoIICoIII6(OH)14(CO3)9(CH3CH2COO)6(dea)12(H2O)30]·(NO3)8·Cl4·(CH3CH2OH)6·(H2O)12 (Ln18Co7, Ln = Gd (1) and Dy (2)) have been obtained by reacting CoCl2·6H2O, Ln(NO3)3·6H2O, and a mixture of ligands consisting of propionate and diethanolamine (H2dea). Crystal structural analysis exhibits two three-blade propellers composed of the CoIII3Ln9 units connected by one CoII ion and three CO32- ions, which assemble into a double-propeller-like structure (Ln18CoIICoIII6). Magnetocaloric effect (MCE) studies indicate that Gd18Co7 exhibits a large entropy change (-ΔSm) of 36.9 J kg-1 K-1.

1544-P: Associations between Dietary Factors and Serum Aryl Hydrocarbon Receptor Bioactivity as a Biomarker of Persistent Organic Pollutants in Prediabetic Population

Aim: Many studies suggest that the persistent organic pollutants (POPs) is a risk factor of type 2 diabetes. The relationship between dietary factors and POPs has been explored recently. POPs are fat-soluble substances that accumulate through the consumption of high fat diets, fish, meat and dairy products. Vegetables and fruits are known to prevent the accumulation of POPs. We aimed to examine the associations between dietary factors and serum cumulative bioactivity of AhR ligand mixture (AhRB) as a biomarker of POPs in subjects at high risk for type 2 diabetes. Methods: We performed a cross-sectional analysis of 304 prediabetic subjects using the Korea National Diabetes Program cohort data. AhRB was divided into quartiles according to the concentrations. (Q1 (the lowest quartile): (Q1 (the lowest quartile): 1.7±0.3, Q2: 2.4±0.2, Q3:3.1±0.2, Q4 (the highest quartile): 3.9±0.2). Socio-demographic, health related-behaviors, and dietary factors were assessed. Dietary factors were collected from the 3-day dietary records and food frequency questionnaire. Results: Starting with the Q1 of AhRB, adjusted mean concentrations of serum triglycerides were 147.06±12.97, 151.30±12.64, 125.80±13.19 and 166.78±13.76 mg/dL for ascending quartiles, respectively (P< 0.05). In the 3Q of AhRB, the highest consumption of sugars (Q3: 13.6±11.6g, P=0.016) and dairy products (Q3: 117.0±126.6g, P=0.032) were shown compared to those of other three groups. On multiple linear regression analysis, high consumption of dairy products (P< 0.05) and fried fish with oil (P < 0.05) were significantly positive associated with serum AhRB concentration after adjusting covariates. Conclusion: This study found an association between dietary factors and AhRB level, however, further longitudinal studies are needed to clarify the effects of these dietary factors on POP levels. Disclosure S. Chon: None. H. Lim: None. J. Kim: None. S. Oh: None.

Numerical Simulation of Non-Linear Models of Reaction—Diffusion for a DGT Sensor

In this work, we present a novel strategy for the numerical solution of a coupled system of partial differential equations that describe reaction–diffusion processes of a mixture of metals and ligands that can be absorbed by a sensor or a microorganism, in an aqueous medium. The novelty introduced in this work consisted of an adequate database management in conjunction with a direct iterative schema, which allowed the construction of simple, fast and efficient algorithms. Except in really adverse conditions, the calculation is converging and satisfactory solutions were reached. Computing times showed to be better than those obtained with some commercial programs. Although we concentrate on the solution for a particular system (Diffusive Gradients in Thin Films [DGT] sensors), the proposed algorithm does not require major modifications to consider new theoretical or experimental configurations. Since the quality of numerical simulations of reaction–diffusion problems often faces some drawbacks as the values of reaction rate constants increase, some additional effort has been invested in obtaining proper solutions in those cases.

Serum biomarkers from cell-based assays for AhRL and MIS strongly predicted the future development of diabetes in a large community-based prospective study in Korea

Exposure to environment-polluting chemicals (EPC) is associated with the development of diabetes. Many EPCs exert toxic effects via aryl hydrocarbon receptor (AhR) and/or mitochondrial inhibition. Here we investigated if the levels of human exposure to a mixture of EPC and/or mitochondrial inhibitors could predict the development of diabetes in a prospective study, the Korean Genome and Epidemiological Study (KoGES). We analysed AhR ligands (AhRL) and mitochondria-inhibiting substances (MIS) in serum samples (n = 1,537), collected during the 2008 Ansung KoGES survey with a 4-year-follow-up. Serum AhRL, determined by the AhR-dependent luciferase reporter assay, represents the contamination level of AhR ligand mixture in serum. Serum levels of MIS, analysed indirectly by MIS-ATP or MIS-ROS, are the serum MIS-induced mitochondria inhibiting effects on ATP content or reactive oxygen species (ROS) production in the cultured cells. Among 919 normal subjects at baseline, 7.1% developed impaired glucose tolerance (IGT) and 1.6% diabetes after 4 years. At the baseline, diabetic and IGT sera displayed higher AhRL and MIS than normal sera, which correlated with indices of insulin resistance. When the subjects were classified according to ROC cut-off values, fully adjusted relative risks of diabetes development within 4 years were 7.60 (95% CI, 4.23–13.64), 4.27 (95% CI, 2.38–7.64), and 21.11 (95% CI, 8.46–52.67) for AhRL ≥ 2.70 pM, MIS-ATP ≤ 88.1%, and both, respectively. Gender analysis revealed that male subjects with AhRL ≥ 2.70 pM or MIS-ATP ≤ 88.1% showed higher risk than female subjects. High serum levels of AhRL and/or MIS strongly predict the future development of diabetes, suggesting that the accumulation of AhR ligands and/or mitochondrial inhibitors in body may play an important role in the pathogenesis of diabetes.

Synergistic Solvent Extraction of Lanthanides(III) with Mixtures of 4-Benzoyl-3-Methyl-1-Phenyl-5-Pyrazolone and Phosphoryl-Containing Podands

The solvent extraction of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu from weak acidic chloride solutions into an organic phase containing 4-benzoyl-3-methyl-1-phenyl-5-pyrazolone (HP) and phosphoryl-containing podands (L) has been studied. A considerable synergistic effect was observed in the presence of neutral ligands L in the organic phase containing HP. The stoichiometry of the Ln(III) extracted species was determined by slope analysis and the equilibrium constants were calculated. It was found that the lanthanide(III) ions are extracted with mixtures of HP and neutral ligands in toluene from weak acidic solutions as LnLP3 complexes.

Solution-processable two-dimensional ultrathin nanosheets induced by self-assembling geometrically-matched alkane

Two-dimensional (2D) nanomaterials have attracted much interest as promising candidates for next generation energy storage, electronics and catalytic applications, due to their unique topology and electronic structure. However, the development of an operable and versatile solution processing technique for simple fabrication of high-quality 2D nanosheets continues to present a significant challenge. Here, an ultrathin indium sulfide nanosheet is synthesized via a simple solution-phase reaction involving two steps: i) thermal decomposition of precursors to form a crystal nucleus; ii) growth of 2D nanosheets in a mixture of amino ligand and alkane solvent. The alkane, matching the amino ligand structure in terms of geometry, could assemble with the ligand to form a soft template and thus induce a 2D arrangement of the nucleus. Moreover, the chemical inertness of the alkane facilitated rotation of crystal seeds, resulting in anisotropic growth of the nanosheet. We further demonstrated that the geometrically matched alkane-assisted solution processing reaction could be applied to synthesize various 2D metal chalcogenides. Functionally, the acquired indium sulfide nanosheets, which possess high photoelectric activity, were introduced for fabrication of photoelectrodes capable of efficient photoelectrochemical water splitting. Our work opens up a new perspective toward the construction and potential applications for various 2D nanomaterials.

Microwave-assisted continuous-flow synthesis of mixed-ligand UiO-66(Zr) frameworks and their application to toluene adsorption

Mixed-ligand metal–organic frameworks (MIXMOFs) containing two or more organic linkers that exhibit functionalities can show improved selective gas adsorption and separation properties with respect to those of the conventional MOFs. In this study, the mixed-ligand UiO–66(Zr) framework was rapidly prepared by employing a microwave-assisted continuous-flow method, which can be easily scaled up for efficient mass production. A microfluidic syringe pump system was used to introduce the precursor solutions of zirconium metal salt and ligand mixture (terephthalic acid and 2-amino terephthalic acid) into a polytetrafluoroethylene tubular reactor kept under microwave irradiation. MIXMOFs were obtained within 10min, a much shorter time than the reaction time required by the conventional heating method. The prepared samples were characterized by N2 porosimetry, field-emission scanning electron microscopy, Fourier transform infrared spectrometry, thermogravimetric, and powder X-ray diffraction analyses to elucidate the effects of the ligand ratios. Furthermore, the toluene adsorption–desorption tests were conducted using the synthesized mixed-ligand UiO–66(Zr) adsorbents at different temperatures.

13C Saturation-Transfer Difference (STD)-NMR Experiments Using INEPT Polarization Transfer

Saturation-transfer difference (STD)-NMR spectroscopy has been widely used to screen potential ligands for binding to large receptor molecules. The STD-NMR experiment is typically based on a proton NMR spectrum, which can suffer from spectral overlap, leading to missing information in STD-based epitope mapping. Two-dimensional STD-NMR experiments can alleviate spectral overlap, but are time consuming. Here, we examine the feasibility of saturating protons in a receptor molecule and observing the STD effect on nearby carbon nuclei after transferring polarization from protons to carbons using the insensitive nuclei enhanced by polarization transfer (INEPT) pulse sequence. We show that under favorable conditions, a 1H→13C STD-INEPT experiment can give information similar to that obtained from a two-dimensional heteronuclear experiment, but in significantly less time. The STD-INEPT experiment could be especially useful when studying mixtures of ligands in which the peak positions in the proton and HSQC spectrum change significantly, and in particular, when using high-throughput, automated methods to analyze the data.

Spectrophotometric Analysis of Ternary Uranyl Systems to Replace Tri-N-butyl Phosphate (TBP) in Used Fuel Reprocessing

In this report, the interaction of monoamide/diamide and monoamide/diglycolamide mixtures with {text{UO}}_{2}^{2 + } are investigated in pH = 1 methanolic nitric acid media. These monoamides include N,N-dimethylacetamide (DMAA), N,N-diethylacetamide (DEAA), N,N-dibutylacetamide (DBAA) and N,N-dibutylbutanamide (DBBA). N,N,N′N′-tetraethylmalonamide (TEMA) and N,N,N′,N′-tetraethyldiglycolamide (TEDGA), which were chosen as model diamides and diglycolamides, respectively. Complex stability constants for each ligand were modelled using the Stability Quotients Using Absorbance Data program using UV–visible data. Complex stoichiometry of ligand mixtures was determined using Job plots and UV–Vis spectrometry. Monoamides were confirmed to produce only disolvate complexes with {text{UO}}_{2}^{2 + } in solution. The log10(K) values for monoamides were found to be independent of amine-side chain length, but were slightly dependent on the carbonyl-side chain length. TEDGA was found to produce multiple uranyl complexes in solution. Job plot data indicated that the uranyl cation strongly prefers to bond either only with the monoamide or diamide in ternary monoamide–diamide–UO2 systems. Monoamide–diglycolamide–UO2 systems were more complicated, with Job plot data indicating the potential for multiple ternary species being present is dependent on the monoamide structure.

Synthesis, structures, and fluorescence properties of one novel Cobalt metal–organic framework based on a tetraphenylethene-core ligand

A new three-dimensional luminescent cobalt (II) metal–organic framework, [Co(Titpe)(bcpf)·(DMF)]·(H2O)2·(DMF) (compound 1, JUST-8) (Titpe = 1,1,2,2-tetrakis(4-(1H-imidazol-1-yl)phenyl)ethane, bcpf = 4,4′-sulfonyldibenzoic acid; DMF = N, N-dimethylformamide), has been solvothermally synthesized by using CoCl2·6H2O and a mixture of ligands: Titpe ligand and bcpf ligand. Single crystal X-ray analysis reveals that 1 crystallizes in the triclinic system and [Formula: see text] space group with a = 13.2097(14) Å, b = 13.9519(14) Å, c = 14.4413(15) Å, α = 89.949(7)°, β = 70.303(7)°, γ = 80.322(7)°, V = 2465.7(5) Å3, Z = 2, Mr =1032.97, Dc = 1.391 g/cm3, μ = 0.455 mm−1, F(000) = 1070, R = 0.0585, and wR = 0.1540 for 8674 observed reflections ( I > 2σ( I)). Its overall structure is a double-fold interpenetrated framework, and it shows a porosity of 12.97% based on a calculation by PLATON and a 4- c type topological network with the point symbol of {6^5.8}. The Co atom bridges the Titpe ligands to form the one-dimensional chains into a two-dimensional layered structure and then connects the auxiliary ligands to get a three-dimensional structure. Compound 1 showed a blue fluorescence emission with the peak maximum at 431 nm (λex = 314 nm).