Tetronic acids, 4-hydroxy-5H-furan-2-ones, constitute a class of heterocyclic compounds with potent biological and pharmacological activity. The beta, beta'-tricarbonyl moiety plays an integral role in biological systems and forms a variety of metal complexes. In this report, we present the complexation reactions of 3-ethoxycarbonyl tetronic acids with acetates and chlorides of Cu(II) and Co(II...

The interaction o f the antibiotic tetracycline with a few metal ions, esp. Cu(II), in different so l­ vents has been investigated by means o f IR, ESR, and UV/VIS spectroscopy. It could be shown that the site o f complexation depends on the solvent used. In DM SO the interaction occurs mainly via the A ring. In water (pH = 5.7) and octanol, the A chromophore as well as the BCD entity o f the m...

The synthesis, complexation properties and catalytic activities under phase-transfer (PT) conditions of differently substituted cyclohexapeptoids are reported. Association constants, for small cationic alkali, and catalytic performances, in a model nucleophilic substitution, are comparable to those of representative crown ethers. Noteworthy, the N-[2-(2-methoxyethoxy)ethyl] side chain derivativ...

We explore the computational power of biochemistry with respect to basic chemistry, identifying complexation as the basic mechanism that distinguishes the former from the latter. We use two process algebras, the Chemical Ground Form (CGF) which is equivalent to basic chemistry, and the Biochemical Ground Form (BGF) which is a minimalistic extension of CGF with primitives for complexation. We ch...

the effect of alkyl substituents on the c-phenyl and/or the n-phenyl ring of benzophenylhydroxamic acid on their molecular structure and hydrogen bonding has been investigated. the predominant configuration in chcl3 is determined by steric and electronic effects. substituents on the c-phenyl ring favor the cis configuration, while substituents in the n-phenyl ring favor a trans configuration. t...

covalent grafting of mcm-41 with 3-chloropropyl trimethoxysilane and subsequent reaction respectively with acacdien and complexation with moo2(acac)2 afforded moo2acacdien@mcm-41. x-ray diffraction and nitrogen sorption analyses revealed the preservation of the textural properties of the support as well as accessibility of the channel system despite sequential reduction in surface area, pore vo...

This research was undertaken with an aim to formulate dextromethorphan hydrobromide as extended release micropellets. The Preformulation studies were carried out on drug Dextromethorphane Hydrobromide and it shows that Drug has good flow property. Various ion exchange resins screened for complexation the ratio of drug: resin optimized along manufacturing process complexation. Drug-Resin complex...

Introduction: Owing to its optimal nuclear properties, ready availability, low cost and favorable dosimetry, Tc continues to be the ideal radioisotope for medical imaging applications. Most of the bifunctional chelators reported for Tc complexation, suffer from tedious labeling protocols and undesired physicochemical properties. On the other hand, bifunctional chelators based on tetraamine fram...

Complexation of Zr(IV) by humic acid (HA) and polyacrylic acid (PAA) is investigated from the point of view of the organic ligand. STXM spectromicroscopy and C 1s-NEXAFS point to different interaction mechanisms between Zr(IV) cations and oxo/hydroxo colloids and PAA. Under conditions where the metal aquo ion is stable, strong complexes are formed. In contrast, unspecific surface coating is ide...

We consider the phase behavior of polymeric systems by calculating the structure factors beyond the Random Phase Approximation. The effect of this correction to the mean-field RPA structure factor is shown to be important in the case of coulombic systems. Two examples are given: simple electrolytes and mixtures of incompatible oppositely charged polyelectrolytes. In this last case, all former s...