A set of indicator molecules was selected and applied to elaborate an NMR-based pH determination method, free of glass electrode errors in highly basic media. Accurate measurement of pH values and protonation constants was achieved by a successive build-up of overlapping, increasingly high pH solutions, using a collection of 8 compounds of appropriately incremented basicities. In order to verif...

The present study investigates the binding properties of four dansyl substituted aza-crown ethers with alkali, alkaline earth metal ions and ammonium. The influence of the solvent polarity and protonation on the photophysical properties of the compounds was studied by UV/Vis and fluorescence methods. The host species caused only slight changes on the absorption spectra of the ligands. The fluor...

3-Hydroxy-1,2-dimethylpyridin-4(1H)-one (deferiprone) is a successful iron chelator, which has been widely investigated for its activity in mitigating iron overload and in protecting against oxidative stress due to Reactive Oxygen Species (ROS). Herein, we present the synthesis, characterisation, physicochemical properties and antioxidant activity of two novel bioconjugates of β-cyclodextrin be...

Biofilms are often associated with human bacterial infections, and the natural tolerance of biofilms to antibiotics challenges treatment. Compounds with antibiofilm activity could become useful adjuncts to antibiotic therapy. We used norspermidine, a natural trigger for biofilm disassembly in the developmental cycle of Bacillus subtilis , to develop guanidine and biguanide compounds with up to...

protonation of the reactive intermediates generated in the raction between dalkyl acetylenedicarboxylates and triphenylphosphine by isonitrosoacetophenone leads to vinyltriphenylphosphonium salts, which undergo intramolecular wittig reaction to produce dalkyl 4-phenyl-n-hydroxypyrrole-2,3-dicarboxylates in moderate yields.

Abstract The stability constants of some the binary and ternary system involving Nickel(II) have been studied. Bis-(pyridyl) benzilidene acts as a primary ligand. Glycine, L-alanine, L-phenylalanine, L-leucine L-valine were secondary complex are calculated by SCOGS computer program. reported values ± 0.02 log unit accuracy. protonation increase with an increasing percentage dimethyl sulphoxide....

Determining the surface protonation behavior of natural adsorbents is essential to understand how they interact with their environments. ProtoFit is a tool for analysis of acid–base titration data and optimization of surface protonation models. The program offers a number of useful features including: (1) enables visualization of adsorbent buffering behavior; (2) uses an optimization approach i...

the stability constants of species present in the systems ni(ii)-pyridoxamine(pym)(a) and ni(ii)-pyridoxamine(pym)(a)-imidazole containing ligands(b) [b = imidazole(him),  benzimidazole(bim), histamine(hist) and l-histidine(his)] have been determined ph-metrically using the miniquad computer program. the existence of the species niah, nia and nia2 was proven for the ni(ii)-pym(a) system, wherea...