In-site mineralization of amorphous calcium carbonate particles: A facile and efficient approach to fabricate poly(l-lactic acid) based hybrids

The aim of this investigation is to obtain a polymer-based hybrid material with biodegradability, biocompatibility, and good mechanical properties and this object was realized via. in-situ introduction of the unmodified calcium carbonate (CaCO₃) into a poly(l-lactic acid) (PLLA) matrix. As verified by the measurements from scanning electron microscopy (SEM), optical microscopy, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), the hybrid films which possesses a uniform dispersion of calcium carbonate CaCO₃ in nano-meter scale, mechanically robustness and thermal stability could be fabricated by a mineralization-alike process. For example, the storage modulus increases from 441 MPa of neat PLLA to 1034 MPa of hybrid film containing 2% (w/w) CaCO₃. In addition, the hybrid films display a significant improvement in its UV-exposure resistance.     

Coexistence of magnetic and electric orderings in the metal-formate frameworks of [NH4][M(HCOO)3

A family of three-dimensional chiral metal-formate frameworks of [NH(4)][M(HCOO)(3)] (M = Mn, Fe, Co, Ni, and Zn) displays paraelectric to ferroelectric phase transitions between 191 and 254 K, triggered by disorder-order transitions of NH(4)(+) cations and their displacement within the framework channels, combined with spin-canted antiferromagnetic ordering within 8-30 K for the magnetic members, providing a new class of metal-organic frameworks showing the coexistence of magnetic and electric orderings.     

Domino reaction for the chemo- and stereoselective synthesis of trans-2,3-dihydrobenzofurans from N-thiophosphinyl imines and sulfur ylides

A novel domino annulation between sulfur ylides and salicyl N-thiophosphinyl imines was developed. The method allows the synthesis of a highly substituted trans-2,3-dihydrobenzofuran skeleton with high yield and excellent chemo- and stereoselectivity.     

A facile synthesis of β-allenyl furanimines via Pd-catalyzed cyclization of 2,3-allenamides with propargylic carbonates

The Pd(OAc)₂/TFP-catalyzed cyclization reaction of 2,3-allenamides in the presence of propargylic carbonates provides an efficient route to β-allenyl furanimine derivatives. Preliminary mechanistic study showed that this reaction was probably initiated by Pd(0) species.     

Hydrothermal synthesis, crystal structure and third-order non-linear optical property of a discrete decanuclear iodocuprate(I) [Cu10H2I16] with [Ni(phen)3] as a template

The title compound [Ni^II(phen)₃]₂[Cu₁₀H₂I₁₆] 1 (phen=1,10-phenanthroline, C₁₂H₈N₂) was hydrothermally synthesized from a simple reaction of CuI-NiCl₂·6H₂O-phen·H₂O-H₂O. X-ray analysis revealed that it consists of NiN₆²⁺ core cation and decanuclear iodocuprate(I) anion together with two dissociative H⁺ ions. In anionic unit, the discrete decanuclear iodocuprate(I) is formed by crystallographically independent five monovalent copper atoms and eight iodine atoms via an inversion center. There exist two types of Cu(I) coordination sites; only one copper(I) atom is in a highly distorted triangular planar site, and the other four copper(I) atoms display the tetrahedral geometries. It deserves to be noted that four types of bridging modes of I⁻ ions in which two are ordinary μ₂- and μ₃-bonding modes can be found. But the other two are the rectangle planar geometry and the novel μ₄-bridge like an “umbrella”, and both of them are rather rare in the halocuprates(I). Compound 1 was crystallized in triclinic space group with a=11.6861(17), b=14.590(2), c=14.649(2) Å, α=76.370(2), β=70.830(2), γ=81.320(3)^o, R=0.075, and was characterized by elemental analysis, IR spectrum and UV-VIS spectrum. The third-order non-linear optical property of 1 was also investigated and the compound exhibits the reverse saturable absorption and self-defocusing performance.     

Determination of aflatoxins in peanuts by matrix solid-phase dispersion and liquid chromatography

A new method based on matrix solid-phase dispersion (MSPD) extraction was studied to determine aflatoxin B1, B2, G1 and G2 from peanuts. Optimization of different parameters, such as type of solid supports for matrix dispersion and elution solvents were carried out. The method used 2 g of peanut sample, 2 g of C18 bonded silica as MSPD sorbent and acetonitrile as eluting solvent. Recoveries of each aflatoxin spiked to peanut samples at 2.5 ng/g (5 ng/g for aflatoxin G2) level were between 78 and 86% with relative standard deviations ranging from 4 to 7%. The limits of quantification ranged from 0.125 to 2.5 ng/g for the four studied aflatoxins using liquid chromatography (LC) with fluorescence detection. In addition, LC coupled to mass spectrometry with an electrospray interface was used for confirmation of aflatoxins present in real samples. Eleven peanut samples from different countries were analyzed by the proposed method and by using an enzyme-linked immunosorbent assay (ELISA). ELISA test is a good screening method for investigation of these mycotoxins in peanut samples.     

Mild electrophilic trifluoromethylation of beta-ketoesters and silyl enol ethers with 5-trifluoro methyldibenzothiophenium tetrafluoroborate

Cyclic and acyclic beta-ketoesters were efficiently trifluoromethylated with 5-trifluoromethyldibenzothiophenium tetrafluoroborate in the presence of a phase-transfer catalyst to afford the corresponding alpha-substituted alpha-trifluoromethyl beta-ketoesters in good to excellent yields. In a second approach, 5-trifluoromethyldibenzothiophenium tetrafluoroborate and tetrabutylammonium difluorotriphenylstannate were used for efficient electrophilic trifluoromethylation of various silyl enol ethers leading to the corresponding alpha-trifluoromethyl ketones in good to high yields.     

Reversed stereoselectivity in iodohydroxylation of allenyl sulfides. An efficient synthesis of (Z)-3-organosulfur-2-iodo-2-propenols

[reaction: see text] It is observed that the iodohydroxylation of 1,2-allenyl sulfides with I(2) and water in aqueous acetone showed Z-selectivity, which is opposite to that of the iodohydroxylation of 1,2-allenyl sulfoxides.     

Efficient degradation of organic pollutants mediated by immobilized iron tetrasulfophthalocyanine under visible light irradiation

Supported iron tetrasulfophthalocyanine can efficiently catalyze the degradation of organic pollutants by H2O2 under visible light irradiation in an aqueous solution, and the catalyst can be easily recycled without apparent loss of activity.