A highly efficient PET switch on-off-on fluorescence receptor based on calix[4]arene for the selective recognition of Cd2+ and Sr2+.

A novel PET (photoinduced electron transfer) based substituted calix[4]arene fluoroionophore has been synthesized and used for the selective recognition of Cd(2+) and Sr(2+) by emission spectra. The detection limit of the synthesized receptor was found to be 0.94 pM for Cd(2+) and 1.04 pM for Sr(2+). Moreover, this probe has been applied to the recognition of Cd(2+) and Sr(2+) in waste water.

Novel cationic quinazolin-4(3H)-one conjugated fullerene nanoparticles as antimycobacterial and antimicrobial agents.

A series of novel cationic fullerene derivatives bearing a substituted-quinazolin-4(3H)-one moiety as a side arm were synthesized using the 1,3-dipolar cycloaddition reaction of C60 with azomethine ylides generated from the corresponding Schiff bases of substituted quinazolinones. The synthesized compounds 5a-f were characterized by elemental analysis, FT-IR, 1H NMR, 13C NMR, and ESI-MS and screened for their antibacterial activity against Mycobacterium tuberculosis (H37RV) and antimicrobial activity against selected Gram-positive (Staphylococcus aureus and S. pyogenes) and Gram-negative (Pseudomonas aeruginosa, Klebsiella pneumonia and Escherichia coli) bacterial and fungal strains (Candida albicans, Aspergillus clavatus, and A. niger), respectively. All the compounds exhibited significant activity, with the most effective compounds having MIC values and zones of inhibition comparable to those of standard drugs.

An ICT based "turn on/off" quinoline armed calix[4]arene fluoroionophore: its sensing efficiency towards fluoride from waste water and Zn2+ from blood serum.

A novel structurally simple calix[4]arene appended 8-amidoquinoline linked conjugate was synthesized and has been used as a turn-on fluorescence probe for Zn(2+) and turn off fluorescence probe for F(-). Moreover, this probe has been applied for Zn(2+) detection in blood serum upto 8.7 µM and fluoride detection upto 22 nM in waste water samples, using emission spectra.

Calix[4]arene based 1,3,4-oxadiazole and thiadiazole derivatives: design, synthesis, and biological evaluation.

In the present investigation, we describe some novel calixarene based heterocyclic compounds (5a-5i) in which 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives have been coupled with 5,11,17,23-tetra-tert-butyl-25,27-bis(chlorocarbonyl-methoxy)-26,28-dihydroxy calix[4]arene. All the newly synthesized calixarene based heterocyclic compounds have been characterized by elemental analysis and various spectroscopic methods like FTIR, (1)H NMR, (13)C NMR, and FAB-MS. All the final scaffolds have been subjected to antioxidant activity, in vitro antimicrobial screening against two gram (+ve) bacteria (S. aureus, S. pyogenes), two gram (-ve) bacteria (E. coli, P. aeruginosa) and two fungal strains (C. albicans, A. clavatus) and also have been screened for their antitubercular activity against Mycobacterium tuberculosis H(37)Rv.

Novel monohydrogenphosphate ion-selective polymeric membrane sensor based on phenyl urea substituted calix[4]arene.

A highly selective and sensitive PVC membrane, containing phenylurea substituted calix[4]arene was found to be a suitable ionophore for monohydrogen phosphate (HPO(4)(2-)) ions that exhibited a Nernstian response (with a slope of -29.4 ± 0.3 mV decade(-1)). The working concentration range of the electrode was 6.0 × 10(-8)-1.0 × 10(-1) mol L(-1) with a detection limit of 2.0 × 10(-8) mol L(-1). The response time of the sensor in the whole concentration range is very short (<8s), with a considerable lifetime of at least 15 weeks. The sensor possesses the advantages of short response time, low detection limit and a high selectivity towards a large number of inorganic anions. The developed sensor was used as an indicator electrode in potentiometric titration of monohydrogen phosphate ion with barium chloride. The proposed sensor was successfully applied for the direct determination of monohydrogen phosphate in real life samples.

Azo calix[4]arene based neodymium(III)-selective PVC membrane sensor.

We found that the PVC membrane, containing azo calix[4]arene is a suitable ionophore, exhibited a Nernstian response for neodymium (Nd(3+)) ions (with slope of 19.8±0.2 mV decade(-1) for the triply charged ion) over a wide linear range of 4.0×10(-8) to 1.0×10(-1) mol L(-1) with a detection limit 1.0×10(-8) mol L(-1), a relatively fast response time, in the whole concentration range (<10 s), and a considerable life time at least for four months in the pH range of 4.0-8.0. Furthermore, the electrode revealed high selectivity with respect to all the common alkali, alkaline earth, transition and heavy metal ions, including the members of the lanthanide family other than Nd(3+). Concerning its applications, it was effectively employed for the determination of neodymium ions in industrial waste water as well as in lake water.