Solvent- and metal-directed lanthanide-organic frameworks based on pamoic acid: observation of slow magnetization relaxation,magnetocaloric effect and luminescent sensing

Two types of lanthanide coordination polymers, namely, [Ln(PA)(NO_3)(DMA)_3]_n(Ln=Gd(1), Dy(2), Eu(3), Tb(4))(type I), and {[Ln_2(PA)_3(DMF)_4]·2DMF}(Ln=Eu(5), Tb(6))(type II)(PA=Pamoic acid, DMA=dimethylacetamide,DMF=N,N-dimethylformamide), have been synthesized by the reaction of Ln(NO_3)_3·6H_2O with pamoic acid through layer diffusion method. These complexes were characterized by single crystal X-ray diffraction, infrared spectroscopy(IR),thermogravimetric analysis(TGA), fluorescence and magnetic measurements. Solvents and lanthanide atoms in the reaction play an important role in controlling different structures. Type I demonstrated 1-D linear chain structure connected by Ln atoms and PA ligands. Type II exhibited non-interpenetrating 3-D 6-connected 4_36~(12) nets based on binuclear [Ln_2(CO_2)_6(DMF)_4] cores.Magnetic properties of complexes 1–4 were investigated in details. Complex 1 shows significant magnetocaloric effect with–ΔS_m=20.37 J kg~(–1) K~(–1) at 3.0 K and 7 T. Complex 2 exhibits slow relaxation of the magnetization. Complexes 3–6 exhibit both ligand- and metal-centered fluorescent properties. Complex 6 demonstrates fluorescent sensing of DMF and Cu~(2+) ion.     

Fullerenes C100 and C108: new substructures of higher fullerenes

Structural Chemistry - Based on our approach of theoretical modeling of the fullerene molecule electronic structures, an analysis of the molecular structures of isolated pentagon rule (IPR) isomer...     

Preparation of glutathione loaded nanoemulsions and testing of hepatoprotective activity on THLE-2 cells

To improve bioavailability and stability of hydrophobic and hydrophilic compounds, nanoemulsions are good alternatives as delivery systems because of their nontoxic and nonirritant nature. Glutathione (GSH) suffers from low stability in water, where its encapsulation in nanoemulsions is a powerful strategy to its stability in aqueous systems. The aim of this study was to obtain nanoemulsions from the hydrophobic/hydrophilic contents of N. sativa seed oil so as to improve GSH stability along with bioavailability of N. sativa seed oil. Then, the prepared nanoemulsions were tested for in vitro hepatoprotective activity against ethanol toxicity. To the best of our knowledge, there is no study on the test of nanoemulsions by the combination of Nigella sativa seed oils and GSH in hepatoprotective activity. Here, nanoemulsions with different contents were prepared using Nigella sativa seed oils. Content analyses and characterisation studies of prepared nanoemulsions were carried out. In order to investigate the protective effects against to ethanol exposure, THLE-2 cells were pretreated with nanoemulsions for 2 h with the maximum benign dose (0.5 mg/mL of nanoemulsions). Ethanol (400 mM) was introduced to pretreated cells and nontreated cells for 48- or 72-h periods, followed by cell viability assay was carried out. Fluorescence microscopy tests revealed the introduction of the nanoemulsions into THLE-2 cells. The findings show that nanoformulations have promising in vitro hepatoprotective effects on the THLE-2 cell line against ethanol exposure.     

Abraham Model Correlations for Triethylene Glycol Solvent Derived from Infinite Dilution Activity Coefficient,Partition Coefficient and Solubility Data Measured at 298.15 K

A gas chromatographic headspace analysis method was used to experimentally determine gas-to-liquid partition coefficients and infinite dilution activity coefficients for 29 liquid organic solutes dissolved in triethylene glycol at 298.15 K. Solubilities were also determined at 298.15 K for 23 crystalline nonelectrolyte organic compounds in triethylene glycol based on spectroscopic absorbance measurements. The experimental results of the headspace chromatographic and spectroscopic solubility measurements were converted to gas-to-triethylene glycol and water-to-triethylene glycol partition coefficients, and molar solubility ratios using standard thermodynamic relationships. Expressions were derived for solute transfer into triethylene glycol by combining our measured experimental values with published literature data. Mathematical correlations based on the Abraham model describe the observed partition coefficient and solubility data to within 0.16 log₁₀ units (or less).     

Large sublattices in subsets of Banach lattices

A classical problem (initially studied by N. Kalton and A. Wilansky) concerns finding closed infinite dimensional subspaces of X / Y, where Y is a subspace of a Banach space X. We study the Banach lattice analogue of this question. For a Banach lattice X, we prove that X / Y contains a closed infinite dimensional sublattice under the following conditions: either (i) Y is a closed infinite codimensional subspace of X, and X is either order continuous or a C(K) space, where K is a compact subset of \({\mathbb {R}}^n\); or (ii) Y is the range of a compact operator.     

辅助配体调控的荧光Cd-MOFs: 乙酰丙酮的荧光增强和Cr(Ⅵ)的荧光猝灭

将柔性苄氨基三羧酸配体5-(3-羧基-4-甲氧基苄氨基)间苯二甲酸(H₃L)与硝酸镉和不同含氮配体在溶剂热条件下反应, 制得了配合物{[Cd(HL)(bpea)·H₂O]·H₂O·DMF}_n(1)、 {[Cd(HL)(bpp)·H₂O]·2H₂O·DMF}_n(2)和 {[Cd(HL)(dmbpy)]·DMF}_n(3)[bpea=bis(4-pyridyl)ethane; bpp=1,3-bis(4-pyridyl)propane; dmbpy=5,5′-dimethyl-2,2′-bipyridine]. 3个配合物分别表现出有趣的2D→2D穿插结构和一维带状结构. 荧光性质测试结果表明, 所有配合物的荧光均可被Cr₂O₇^2?猝灭, 而在乙酰丙酮的DMF溶液中, 只有配合物1表现出明显的荧光增强. 羧酸配体的柔性、 含氮配体的类型和结构可以调控配合物的结构和荧光性能.     

Asymmetric Synthesis of 1,3-Diamines. II: Diastereoselective reduction of atropisomeric N-tert-butanesulfinylketimines

Chiral, nonracemic o-aminobenzylamines were prepared in a highly diastereoselective reduction of atropisomeric N-tert-butanesulfinylketimines. The ortho-substituent ensures the distinct reactivity of atropisomers 4d-f. The free energy of activation for atropisomerization of sulfinylimines 4d-f in THF-d(8) was determined by NMR methods to range from 70.8 to 97.9 kJ/mol.     

Formation and dynamics of van der Waals molecules in buffer-gas traps

We show that weakly bound He-containing van der Waals molecules can be produced and magnetically trapped in buffer-gas cooling experiments, and provide a general model for the formation and dynamics of these molecules. Our analysis shows that, at typical experimental parameters, thermodynamics favors the formation of van der Waals complexes composed of a helium atom bound to most open-shell atoms and molecules, and that complex formation occurs quickly enough to ensure chemical equilibrium. For molecular pairs composed of a He atom and an S-state atom, the molecular spin is stable during formation, dissociation, and collisions, and thus these molecules can be magnetically trapped. Collisional spin relaxation is too slow to affect trap lifetimes. However, (3)He-containing complexes can change spin due to adiabatic crossings between trapped and untrapped Zeeman states, mediated by the anisotropic hyperfine interaction, causing trap loss. We provide a detailed model for Ag(3)He molecules, using ab initio calculation of Ag-He interaction potentials and spin interactions, quantum scattering theory, and direct Monte Carlo simulations to describe formation and spin relaxation in this system. The calculated rate of spin-change agrees quantitatively with experimental observations, providing indirect evidence for molecular formation in buffer-gas-cooled magnetic traps. Finally, we discuss the possibilities for spectroscopic detection of these complexes, including a calculation of expected spectra for Ag(3)He, and report on our spectroscopic search for Ag(3)He, which produced a null result.     

Aluminum avoids the central position in AlB9- and AlB10-: photoelectron spectroscopy and ab initio study

The structures and the electronic properties of two Al-doped boron clusters, AlB(9)(-) and AlB(10)(-), were investigated via joint photoelectron spectroscopy and high-level ab initio study. The photoelectron spectra of both anions are relatively broad and have no vibrational structure. The geometrical structures were established by unbiased global minimum searches using the Coalescence Kick method and comparison between the experimental and calculated vertical electron detachment energies. The results show that both clusters have quasi-planar structures and that the Al atom is located at the periphery. Chemical bonding analysis revealed that the global minimum structures of both anions can be described as doubly (σ- and π-) aromatic systems. The nona-coordinated wheel-type structure of AlB(9)(-) was found to be a relatively high-lying isomer, while a similar structure for the neutral AlB(9) cluster was previously shown to be either a global minimum or a low-lying isomer.