Small molecules representing common synthetic polymers were subjected to photochemically induced hydrogen abstraction by benzophenone. Reactions were monitored using (1) H NMR to query the factors that influence preferential abstraction of protons in unique chemical environments. Differences in bond dissociation energies do not fully explain the observed hydrogen abstraction preferences. To tha...

The complexation reactions between Cu2+, Pd2+ and Ni2+ metal ions with promethazine (PM) in water or DMF were studied by the spectrophotometric methods at [(15, 25,35 and 45±0.1) °C]. The complexation process was optimized in terms of pH, temperature and contact time. The stoichiometry of the complex was found to be 1:1 (metal ion/ligand). The formation constants of the resulting complexes were...

We present a theory of the complexation of polyanions by divalent cations. The formation of both mono-and dicomplexes is possible. Monocomplexation locally inverts the charge of the polyelectrolyte and transforms it into a polyampholyte. The formation of a dicomplex creates a bridge between charged monomers. The complexation constants for mono and dicomplexation strongly decrease at high ionic ...

A simple and sensitive spectrophotometric method was developed for the determination of Oxacillin sodium. The method was based on charge transfer complexation reaction of the drug with iodine in methanol - dichloromethane medium. The absorbance was measured at 365 nm against the reagent blank. Under optimized experimental conditions, Beer's law is obeyed in the concentration ranges 2-8 μg/ml fo...

Pyranine as a new class of fluorescent chemosensor for the Cu(+) ion is reported. The probe is capable of discriminating ranges of cations from the Cu(+) ion, even in competing environment. The dye displayed a rapid fluorescence response (t1/2 = 1.66 min) towards the Cu(+) ion, and the micromolar detection limit enabled the detection of the ion in environmental samples. The observed stoichiomet...

The employment of cyclodextrin host-guest complexation to construct supramolecular assemblies with an emphasis on polymer networks is reviewed. The main driving force for this supramolecular assembly is host-guest complexation between cyclodextrin hosts and guest groups either of which may be discrete molecular species or substituents on a polymer backbone. The effects of such complexation on p...

A bifluorophoric molecule (1) capable of intramolecular Förster Resonance Energy Transfer (FRET) is reported. The emission intensity of the FRET acceptor in 1 depends on the molar absorptivity of the donor, which is a function of zinc(II) complexation. The FRET dynamics of [Zn(1)](ClO4)2 is characterized by femtosecond time-resolved transient absorption spectroscopy. The solvent-mediated relaxa...

New fluorescent ionophores containing the 1-naphthylacetanilide moiety based on oligo-ethylene oxide (1(4) and 1(5)) have been synthesized, and their photochemical behaviors have been studied. In the absence of a metal ion, the 1-naphthylacetanilide moiety showed a weak fluorescence emission (fluorescence "off state"). However, complexation with Ca(2+) induced a large enhancement effect on the ...

Some alkyl and aryl derivatives of 9H-purine-6-thiol were synthesized and evaluated in vitro and in vivo for potential antithyroid effects. Spectrophotometric studies demonstrated 1:1 charge transfer complexation between iodine and these compounds with quite high values of the formation constants. The blood assays of rats treated with these compounds revealed significant antithyroid activity fo...