the interaction between dmso and alkaline earth perchlorates in anhydrous acetonitrile was investigated by ft-ir spectroscopy. a quantitative study was performed to determine the average number of bonded dmso molecules using v (so) and v (c-s) vibrations. changes in coordination numbers were observed both with increasing atomic numbers and the solvent composition. none of the investigated syste...

A new polyvinyl choloride (PVC) membrane sensor for cerium (III) was prepared based on 4,13-didecyl-1,7,10,16-tetraoxa-4,13-diazacyclooctadecane (kryptofix22DD) as an ionophore. The sensor exhibites a linear concentration range of 1.0×10-6 to 1.0×10-1 M, with a Nernstian slope of 18.0±1.0 mV/decade, and a detection limit of 9.7×10-7 M. It has a fast response time (5 s) and can be used for two m...

The binding of alkali and alkaline earth metal cations by macrocyclic and diazamacrobicyclic polyethers, composed of ordered arrays of hard oxygen (and nitrogen) donor atoms, underpinned the development of host-guest supramolecular chemistry in the 1970s and 1980s. The arrangement of -OCCO- and -OCCN- chelating units in these preorganized receptors, including, but not limited to, crown ethers a...

in this study the binding abilities of 1,3-calix[4]biscrown-6 (l) toward ba2+ and ca2+ have beenestablished in methanol by spectrophotometric measurements at 25±0.1 °c and 0.01 m ionicstrength, and with using specfit computer program; stability constants for 2 : 1, metal : ligandcomplexes has been estimated

Novel di-ionizable p-tert-butylcalix[4]arene-1,2-crown-3 ligands in cone and 1,2-alternate conformations were prepared as potential metal ion extractants. Selective bridging of proximal hydroxyl groups of the calix[4]arene platform by a crown-3 polyether unit was achieved under Mitsunobu reaction conditions. In addition to the carboxylic acid group, the acidity tunable N-(X)sulfonyl oxyacetamid...

A thio carboxylic acid derivative: 2-aminocyclopent-1-ene-1-carbodithioic acid (ligand) was synthesized and characterized. It was used as a colorimetric chemo sensor (chads) for Ni. The absorption maximum of ligand and Ni shows a shift from 390 nm to 420 nm in absence of buffer solutions. The change in color is very easily observed by the naked eye, while other metal cations, such as Fe, Co, Hg...

Two new orthophosphates, BaMn2Fe(PO4)3 [barium dimanganese(II) iron(III) tris-(orthophosphate)] and SrMn2Fe(PO4)3 [strontium dimanganese(II) iron(III) tris-(orthophosphate)], were synthesized by solid-state reactions. They are isotypic and crystallize in the ortho-rhom-bic system with space group type Pbcn. Their crystal structures comprise infinite zigzag chains of edge-sharing FeO6 octa-hedra...

Single crystals of α-Ba(2)P(2)O(7), dibarium diphosphate, were obtained under hydro-thermal conditions. The structure belongs to the diphosphate A(2)P(2)O(7) series with A being an alkaline earth cation. α-Ba(2)P(2)O(7) crystallizes isotypically with α-Sr(2)P(2)O(7). All atomic sites have site symmetry m with the exception of two O atoms which reside on general positions. Both Ba(2+) cations ar...

Kinetics of the cleavage of two phosphate diesters, bis(4-nitrophenyl) phosphate and 2-hydroxypropyl 4-nitrophenyl phosphate and a triester, 4-nitrophenyl diphenyl phosphate, in the presence of Mg(II), Ca(II) and Sr(II) were studied in 90% vol. DMSO at 37 degrees C. The alkaline hydrolysis of the triester was inhibited by all cations, but with both phosphodiesters strong catalytic effects were ...

Alkali metal and alkaline earth cations pass readily through the acetylcholine receptor channel. Monovalent cations with larger crystal radii are more permeant than ones with smaller radii. For divalent ions, this selectivity sequence is reversed: smaller ions are more permeant than larger ones. This reversal in selectivity sequence with change of valence from 1 to 2 can be naturally accounted ...