A Study of the Encapsulation of Nickel Phthalocyanine in Molecular Sieve Zeolites of the FAU Type

Nickel(II)phthalocyaninate spectroscopy (NiPc) was synthesized in the supercages of zeolite FAU by the template synthesis method at two different temperatures of 200 and 300°C and characterized by diffuse reflectance spectroscopy, UV-Vis spectroscopy, X-ray powder diffraction, and IR. The results show that the catalyst synthesized at 200°C contains a higher amount of complex as monomeric species encapsulated in the supercages. At elevated temperature, higher amount of the NiPc may be hosted in the mesopores and/or on the external surface of the zeolite as aggregates.     

A convenient synthesis of 1,5-diarylpyrazoles from Baylis-Hillman adducts using HY-zeolite

<正>A facile and convenient protocol was developed for the synthesis of 1,5-diarylpyrazoles using Baylis-Hillman adducts in the presence of HY-zeolite as an efficient recyclable heterogeneous catalyst in reasonable reaction times(1.5-2.5 h) and high yields (78-90%).     

Contribution of Diffuse Reflectance Spectroscopy to Monitoring the Synthesis Improvement of Encapsulated Complexes

Diffuse reflectance spectroscopy (DRS) can be regarded as a solid state technique contribution to monitoring the process of encapsulation of transition metal complexes into cavities of zeolites. By employing DRS, it was revealed that the effectiveness of a method suggested for higher encapsulation of a tris(bipyridine) cobalt(II) complex into zeolite Y can easily be manifested. In addition to that, simple diffuse reflectance spectra give information about a relative amount of two spin states of the cobalt bipyridine complexes and their alteration upon the method used.__________From Koordinatsionnaya Khimiya, Vol. 31, No. 8, 2005, pp. 618–620.Original English Text Copyright © 2005 by Zanjanchi, Tabatabaeian, Hosseinzadeh.This text was submitted by the authors in English.     

Baeyer-Villiger oxidation of cyclic ketones utilizing potassium peroxydisulfate(K_2S_2O_8) or sodium perborate(NaBO_3) in acidic media

The efficient, green, facile, mild and straightforward conversion procedure for the oxidation of cyclic ketones to lactones at room temperature utilizing potassium peroxydisulfate (K₂S₂O₈) in acidic media is satisfactory to high yields without using traditional chlorinated solvents is reported. This oxidative reagent is cheap and friendly environmental procedure for industrial purposes than use of organic peracids.     

A Fast Response Strontium Ion‐Selective Electrode Prepared by Sol‐Gel Membrane Technique

A sol‐gel electrode, based on 6‐(4‐nitrophenyl)‐2‐phenyl‐4,4‐dipropyl‐3,5‐diaza‐bicyclo [3,1,0] hex‐2‐ene (NPDBH) as a neutral ionophore, was successfully developed for the detection of Sr²⁺ in aqueous solutions. Theoretical calculations confirmed NPDBH selectivity toward strontium in comparison with some other metal ions. The electrode responds to Sr²⁺ ion with a sensitivity of 29.1±0.4 mV/decade over the range 8.0×10^?7–1.0×10^?1 M. Selectivity coefficients determined by matched potential method (MPM) indicate high selectivity for strontium ions. The electrode has a fast response time of 11 s and a working pH range of 3.0–10.0. The sol‐gel electrode shows detection limit of 7.5×10^?8 M.     

Rapid determination of aluminum by UV-vis diffuse reflectance spectroscopy with application of suitable adsorbents

Diffuse reflectance spectroscopy (DRS) can be used as a rapid and sensitive method for the quantitative determination of low amounts of aluminum. In this analytical technique, the analyte in samples are extracted onto a solid sorbent matrix loaded with a colorimetric reagent and then quantified directly on the adsorbent surface. Alternatively, colored aluminum complexes formed in solution can also be immobilized onto adsorbent surface and be measured by DRS technique. Octadecyl silica disk, methyltrioctylammonium chloride–naphthalene and MCM-41 were examined as adsorbents. Eriochrome cyanine R and quinalizarin were used as coloring reagents. Optimal sorption conditions were found for each system of analyte–reagent–adsorbent. The concentration of analyte is determined using the appropriate form of the Kubelka–Munk function. We obtained for each of the aluminium–reagent–adsorbent system a calibration curve by plotting the absorbance versus the log 10²[Al³⁺] μg ml⁻¹. The linear dynamic range extends over two orders of magnitude within 0.01–15 μg ml⁻¹ with little differences in the range and in the correlation coefficients among the adsorbents. We consider that for a rapid determination of aluminum a spot-test-DRS combination with a detection limit of 1.0 × 10⁻² μg ml⁻¹ is the more facile and preferred technique.     

Self-association of rhodamine dyes in different host materials

The aggregation of rhodamine 6G in liquid crystalline solution (anisotropic host) was studied using polarised spectroscopy and in a guest-host system. The self-association of rhodamine B was investigated in molecular sieves of type AlPO(4)-5 (microporous host) using diffuse reflectance spectroscopy. Also, the molecular interaction of rhodamines in normal solvents (isotropic hosts) was studied using visible spectroscopy for comparison. Therefore, the role of the host nature in the different phases on the self-association of the guest molecules has been investigated and compared. The absorption spectrum of the rhodamine dye in liquid crystalline host is affected by a specific interaction related to the alignment by the liquid crystal property as well as solvent polarity. Due to the existence of a large amount of water molecules absorbed into channels and cavities of aluminophosphate molecular sieve, the maximum absorption wavelengths of the dye loaded AlPO(4)-5 is affected by aqueous environment of the aluminophosphate pores.     

The comparison of photocatalytic activity of synthesized TiO2 and ZrO2 nanosize onto wool fibers

TiO₂ and ZrO₂ nanocrystals were successfully synthesized and deposited onto wool fibers using the sol-gel technique at low temperature. The photocatalytic activities of TiO₂-coated and ZrO₂-coated wool fibers were measured by studying photodegradation of methylene blue and eosin yellowish dyes. The initial and the treated samples were characterized by several techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and X-ray diffraction. The TEM study shows dispersed particles with 10-30 nm in size for TiO₂-coated and 20-40 nm in size for ZrO₂-coated samples on the fiber surface. Comparison of the photocatalytic activity of the coated samples reveals superiority of TiO₂ modified sample with respect to that of ZrO₂ for degradation of both dyes. Our observations indicate that by applying this technique to the fabrics, self-cleaning materials could be designed for practical application.     

NMR structural elucidation and photochromic behavior of new 1,3-diazabicyclo[3.1.0]hex-3-ene derivatives

Several 6-(4-nitrophenyl)-4-phenyl-1,3-diazabicyclo[3.1.0]hex-3-ene derivatives having various substituents on C² were synthesized, and their ¹H NMR spectra and photochromic behavior were examined.