Eco-friendly synthesis of high silica zeolite Y with choline as green and innocent structure-directing agent

Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure-directing agents (OSDAs), which are chronically hazardous to humans and the environment. It is a growing trend to develop an eco-friendly and nuisanceless OSDA for zeolite synthesis. Herein, choline is employed as a non-toxic and green OSDA to synthesize high silica Y zeolite with SiO₂/Al₂O₃ ratios of 6.5–6.8. The prepared Y zeolite samples exhibited outstanding (hydro)thermal stability at ultrahigh temperature owing to the higher SiO₂/Al₂O₃ ratio. The XRF, SEM, ²⁹Si-NMR and ¹³Na+ results suggested that choline plays a structure-directing role in the synthesis of Y zeolite, while the feed molar fraction of Na⁺ is a crucial determinant for the framework SiO₂/Al₂O₃ ratio and the crystal morphology.     

C40X2（X=H,F,Cl,Br）的理论研究

应用密度泛函理论在B3LYP/6-31G*水平上对C40X2(X=H,F,Cl,Br)进行研究.研究结果表明,C40X2(X=H,F,Cl,Br)在热力学上是稳定的,卤化衍生物的稳定性随卤素原子序数的增大而降低,最有利的衍生化方式是1-4加成,1-2与1-4加成的卤化和氢化衍生物在所研究的分子中较为稳定.这些研究有助于理解富勒烯衍生物的衍生化模式.     

Synthesis,characterization and crystal structures of two binary acid complexes based on L-glutamate and L-aspartate

Two amino acid complexes, [Cd(L-glu)(H₂O)] _n ?·?nH₂O (1) and [Co(L-asp)(phen)(N₃)]?·?2H₂O (2) (L-glu?=?L-glutamate, L-asp?=?L-aspartate, phen?=?1,10-phenanthroline), have been synthesized and characterized by elemental analyses, IR spectra and TG-DSC analysis. Single crystal X-ray structure analyses revealed that each L-glutamate acts as a pentadentate ligand binding to three octahedral Cd(II) atoms through the amino group and two carboxyl groups to form a neutral helical network. Complex 2 is a mononuclear compound in which Co(III) is octahedrally coordinated by tridentate L-aspartate, monodentate azide and chelating phen ligand. Thermal stability and fluorescence of 1 have been investigated. The complex shows strong blue fluorescence in the solid state.     

硫化锌胶体标准溶液稳定性研究

采用去离子除氧水,由淀粉、乙酸锌、氯化钠、硫化钠等配制了硫化锌胶体标准溶液。实验结果表明,硫化锌胶体标准溶液的吸光度与硫化钠标准溶液基本一致,可以替代硫化钠标准溶液。采用t检验对硫化物胶体标准溶液稳定性进行了检验,表明该法配制的硫化锌胶体标准溶液在室温下可稳定保存2个月,解决了硫化物标准溶液只能现配现标现用的问题。     

The Interaction of Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) with Mixed Donor Macrocycles Containing Pendant Carboxylic Acid Functions

The syntheses of mixed oxygen-nitrogen donor macrocycles incorporating two or three pendant carboxylic acid groups are described. Potentiometric titrations in water (I = 0.1; KNO₃) at 25°C have been used to determine the stability constants for the 1: 1 (metal:ligand) complexes of Co(II). Ni(II), Cu(II), Zn(II), and Cd(II). The constants obtained are compared with the previously determined values for the corresponding complexes of the unsubstituted macrocyclic precursors. The results of these studies indicate that each carboxylate function participates in binding to the central metal. For some metal-ion/ligand systems there is evidence that ring size effects influence the overall stability patterns and that, in such cases, both the ether oxygens as well as the tertiary amines of the macrocyclic rings appear to bind to the metal.     

New biocidal metal complexes of bisphenol-A formaldehyde polymer containing piperazine

The polymeric ligand (BFP) was synthesized by condensation of bisphenol-A, formaldehyde, and piperazine in alkaline medium at 70–80°C. The polymer–metal complexes were synthesized by the reaction of BFP with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) acetates in 1?:?0.5 (ligand?:?metal) molar ratio. All the synthesized polymers were characterized by elemental, spectral (infrared, ¹H-NMR, and UV-Vis), magnetic moment measurements, and thermal (TGA) analysis. The ligand-field and nephelauxetic parameters have been determined from UV-Vis spectra using ligand-field theory. Elemental analyses indicate the association of water with metal for Mn(II), Co(II), and Ni(II), which is also supported by TGA. The antimicrobial activities of the synthesized polymers were studied by agar well diffusion methods against Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, and Shigella boydii. The antimicrobial activity and thermal stability of Cu(II)–polymer were higher than the other polymer–metal complexes due to the higher stability constant of Cu(II).     

Reducing the formation of six-membered ring ester during thermal degradation of biodegradable PHBV to enhance its thermal stability

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) has attracted the attention of academia and industry because of its biodegradability, biocompatibility, thermoplasticity and plastic-like properties. However, PHBV is unstable above 160 °C during melt processing at a temperature above the melting temperature, which restricts practical applications as a commodity material. It is widely believed that thermal degradation of PHBV occurs almost exclusively via a random chain scission mechanism involving a six-membered ring transition state. Here, 2,2′-bis(2-oxazoline) (BOX) was selected to modify PHBV to control the formation of six-membered ring ester during thermal degradation. The resulting hydroxyl-terminated PHBVs (HT-PHBVs) had improved thermal stability due to a decrease in the negative inductive effect of the neighboring group of methylene groups at the β-position to the ester oxygen, and a decrease in the electron-denoting effect of substituent group of carbon atoms at α-position to the ester oxygen. The optimal reaction temperature and time were determined to be 95 °C and 6 h, respectively. Compared with those of original PHBV, the temperature determined at 5% weight loss (T_5%), the initial decomposition temperature (T₀), the maximum decomposition temperature (T_max), the complete decomposition temperature (T_f) of HT-PHBV prepared under the optimal conditions increased by 31, 24, 19 and 19.1 °C, respectively.     

Diastereomeric half-sandwich Ru(II) cationic complexes containing amino amide ligands. Synthesis, solution properties, crystal structure and catalytic activity in transfer hydrogenation of acetophenone

The cationic complexes [(η⁶-arene)Ru(N,O-amino amide)X]Y (arene = p-cymene or indane; N,O-amino amide = (l)-proline amide or (l)-phenylalanine amide; X = Cl or I; Y = Cl, I or PF₆) have been synthesised and fully characterized by spectroscopic and analytical methods. In several cases (1a, 3a, 4a, 4b, 5) the metal configuration has been definitively established by X-ray analysis on single crystal. The lability of the metal center in solution has been studied by ¹H NMR and CD techniques. The highest configurational stability has been found in the complexes of the type [(η⁶-indane)Ru(N,O-proline amide)Cl]Y (4a,b). The complexes 1b, 2a-b, 3b, 4b and 5 are good precatalysts for the transfer hydrogenation of acetophenone in basic i-PrOH, with ee up to 76% at 30 °C. An ESI(+)-MS study of pre-catalytic solutions has provided useful information on the catalytic mechanism.     

Lysozyme as diffusion tracer for measuring aqueous solution viscosity

Measuring tracer diffusion provides a convenient approach for monitoring local changes in solution viscosity or for determining viscosity changes in response to multiple solution parameters including pH, temperature, salt concentrations or salt types. One common limitation of tracer diffusion in biologically relevant saline solutions is the loss of colloidal stability and aggregation of the tracer particles with increasing ionic strength. Using dynamic light scattering to measure tracer diffusion, we compared the performance of two different types of tracer particles, polystyrene nanobeads vs. the small protein lysozyme, for viscosity measurements of saline solutions. Polystyrene beads provide reliable values for water viscosity, but begin flocculating at ionic strengths exceeding about 100 mM. Using lysozyme, in contrast, we could map out viscosity changes of saline solutions for a variety of different salts, for salt concentrations up to 1 M, over a wide range of pH values, and over the temperature range most relevant for biological systems (5–40 °C). Due to its inherently high structural and colloidal stability, lysozyme provides a convenient and reliable tracer particle for all these measurements, and its use can be readily extended to other optical approaches towards localized measurements of tracer diffusion such as fluorescence correlation spectroscopy.