A new PVC membrane potentiometric sensor for Ag(I) ion based on a recently synthesized calix[4]arene compound of 5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-calix[4]arene-thiacrown-4 is developed. The electrode exhibits a Nernstian response for Ag(I) ions over a wide concentration range (1.0 Â 10 À2 À 1.0 Â 10 À6 M) with a slope of 53.8 AE 1.6 mV per decade. It has a relatively fast response time (5 -10 s) and can be used for at least 2 months without any considerable divergence in potentials.

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The present study reports the synthesis of a novel ionophore, calix[4]azacrown (5) bearing two amino groups at the lower rim along with its oligomeric analogue (6). The liquid-liquid extraction properties of these compounds towards selected metal cations and dichromate anions have been evaluated. It is observed that (5) and (6) are good extractants for the selected metal cations. However, in the case of dichromate anion, only species (5) shows remarkable extraction properties at low pH, whereas species (6) shows poor extraction behavior. The results have importance especially in wastewater treatment to obtain environmentally safe industrial effluent and they should also assist supramolecular chemists in designing and synthesizing more sophisticated host molecules for the removal of toxic pollutants.

In this study, a total of six fungal samples were isolated from apple, strawberry and orange pulp. DNA sequence analysis was used as molecular identification method. ITS region was aligned in DNA sequence analysis, and an algorithm sequence similarity was done using BLAST (Basic Local Alignment Search Tool) program to identify these isolates. All the six isolates were identified as Aspergillus fumigates. The total lipid content was varied in the isolates which were ranged from 29.4 to 21.0 mg/100 ml. Moreover, the obtained lipid form mycelium biomass of the isolates was transesterified by a base catalyst. The methyl esters were analyzed by using GC-MS. GC-MS Spectrometry revealed the presence of different fatty acids with long chain (C11:0, C15:0, C17:1, C18:2, C16:1). High efficiency biodiesel can be obtained using long-chain fatty acids. Fatty acid profiles of A. fumigatus isolated from different fruit pulps have confirmed its potentiality as well as showed the beneficial utilization of these fatty acids for biodiesel production.

The synthesis of two new flavin substituted calix [4]arene derivatives, 9 and 10, is described. The first flavin substituted calix[4]arene derivative 9 was synthesized by the reaction of 3-methylalloxazine (5) with 25,27-bis(3-bromopropoxy)-26,28-dihydroxy-5,11,17,23-tetra(tert-butyl)calix[4]arene (4) in high yield (92%). The other derivative 10 was prepared from 3-methylalloxazine-1-acetic acid (7) and 25,27-bis(3-cyanopropoxy)calix[4]arene (3). All new compounds were characterized by a combination of FT-IR and 1 H-NMR spectroscopy, and elemental-analysis techniques.