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The self-assembly process of a supramolecular edifice based on the coordination of europium(III) by a ditopic strand L bearing tridentate bis(benzimidazolyl)pyridine subunits is reported. The thermodynamic and kinetic data allow the prediction of the apparent 'magic' self-assembly by Eu2L3, which is fast and efficient only under a strict set of conditions.

Research was conducted to examine the formation equilibria of four systems which included mp, map (2-(p-anisyl)-1, 10-phenanthroline), Memap (2-(p-anisyl)-9methyl-1,10-phenanthroline) and dap (2,9-di(p-anisyl)-1,10-phenanthroline). The thermodynamic and kinetic characteristics of the corresponding bischelate complexes were related to their structure. Results demonstrate that the sequence of ligands presents an opportunity to systematically explore the electronic and steric effects of aryl and alkyl substituents in alpha position to the nitrogen diimine atoms.

The synthesis, structural characteristics, and coordination properties of a family of three triple-stranded, polytopic ligands were analyzed. Classical measurements was utilized in examining the consequences of the structural changes on the binders' coordination properties and allosteric effects. Results have shown that subtle structural changes have an effect on the binding properties of the compounds.

The importance of both topological and geometrical effects in the knotted structure and interactions of dicopper(I) cations on the demetalation rates and mechanism was determined through single-wavelength and multiwavelength absorption spectrophotometry. Results have shown that the knotted topology radically augments the dicopper interactions. It was also demonstrated that following the release of the first copper (I) cation, a rearrangement in the molecular structure occurs secondary to the entangled nature of the trefoil knots.

The chiral hexadentate rhizoferrin ligand is composed of a pair of coordinating citric acid moieties that are tied together with a diaminobutane linker. The trans citrate hydroxy isomers form octahedral complexes with various metal ions by facial coordination that uses two carboxylates and hydroxy oxygen donor atoms. Rhizoferrins belong to a new class of carboxylate siderophores that adopt a chirality around the opposite metal center.

Examination of pyoverdin PaA, a peptidic fluorescent siderophore excreted by Pseudomonas aeruginosa reveals that the peptidic chain in the bacterium has two hydroxamic acids, three bidentate coordination sites and a dihydroxyquinoline-type function. Stabilities of the complexes of pyoverdin PaA with ferrous and ferric ions are determined by potentiometric, spectrophotometric and cyclic voltammetric techniques. Kinetic studies enable the evaluation of the kinetic parameters for the formation and dissociation of the ferric pyoverdin PaA complexes. Experimental data support the iron biological transport by pyoverdin PaA.

Synthesis of bis-anthracenediyl macrotricyclic receptor helps analyze the relation of cation complexation with fluorescence emission. Two anthracene chromophore-containing flexible spaces connect two diazacrown ether moieties in the macrocycle. Metal cations influence the dual fluorescence emission of the molecule. Spectroscopic studies reveal the influence of complexed cation on the optical properties and X-ray studies demonstrate the presence of two Rb(+) cations within the hydrophilic N2O4 parts. Mono- and binuclear Rb complexes exhibit noncooperative behavior and high stability in solution.

Studies on cezomycin reveal that it forms two complexes with Mg and Ca, similar to those formed by calcimycin. The cezomycin complexes are less stable than the calcimycin complexes. The neutral A2M-cezomycin complex formation includes a cooperative effect at equilibrium.

A spectroscopic study probes into the photophysical and complexation behavior of a new macrotricyclic bisanthracenyl receptor. Apart from monomer-derived signals, the receptor exhibits excimer type fluorescence due to intramolecular interaction between the anthracene and amino chromophores. The study shows that linear alpha,omega-alkanediammonium ions, ((S)n)2+, form 1:1 and 1:2 inclusion complexes with the receptor and, at certain chain lengths (n = 6, 7), the complexed ions suppress the excimer signals.

A new family of linear ferrioxamine B analogs was described. These analogs have been designed to serve as chemical probes of microbial iron(III) uptake systems. Due to the presence of asymmetric carbons the synthetic binders differ from the natural ferrioxamine in forming complexes of preferred chiral configuration. The results suggest that the transport of the siderophore iron(III) complex across the membrane is the determinant factor in these compounds' biological activity.

A versatile synthetic strategy is described that is used for preparing doubly threaded, bistable [c2]daisy chain compounds. Kinetics measurements have shown that the acid/base-promoted extension/contraction movements of the polymeric [c2]daisy chain are faster than those of its monomeric counterpart.

The article explains the binding of various imidazoles to strapped zinc(II) porphyrin receptors. The imidazole binding is found to follow the induced-fit mechanism.

The study presents the design, synthesis and physiochemical characterization of various biomimetic analogues to microbial siderophores based on the fluorescent phenol-oxazoline coordination sites. The coordination event of the tripodal system can be easily monitored, which makes it a perfect candidate for integration with solid-state materials for the development of chip-based devices and analytical methodologies.

A series of ferrioxamine B analogues that target the bacterium Yersinia enterocolitica were prepared. A case is presented in which biomimetic siderophore analogues deliberately designed for a particular bacterium could distinguish between related uptake systems of different microorganisms.

Dentrimers with a Cu(I) bis(2,9-diphenethyl-1,10-phenanthroline) core surrounded by frechet type dendritic branches have been prepared and the kinetics of their cyanide-assisted demetalation studied.

Using physicochemical methods, the coordination properties of the iron(III) and iron(II) complexes of azotobactin (delta) are measured. The redox potential of the azotobactin (delta) iron complexes is consistent with a reductive step by physiological reductants for the iron release in its reduced form Fe(II).

The oxidation chemistry of Fe(III)microperoxidase-8(MP-8) and Mn(III)MP-8 in water at ambient temperature with particular attention to the role played by protons in the formation of iron hydroperoxo and high-valent iron-oxo intermediates is studied. The results show that Compound zero is formed prior to what is analyzed as high-valent metal-oxo peptide radical intermediate.

It is stated that the protonation and iron(II) coordination properties of a bis(2,2'-bipyridine) ligand L were investigated in methanol. Speciation studies of the corresponding ferrous complexes were carried out as a function of pH and iron(II) concentrations.