A systematic comparison of empty tetralactam macrocycles containing 1,3-benzenedicarboxamide, 2,6-pyridinedicarboxamide, and 1,3-adamantanedicarboxamide bridging units finds that macrocycles with adamantyl bridging units exhibit weaker non-covalent affinity for an encapsulated guest. In the case of interlocked squaraine rotaxanes with macrocycles containing phenylene sidewalls, the structural c...

Macrocycles are key structural elements in numerous bioactive small molecules and are attractive targets in the diversity-oriented synthesis of natural product-based libraries. However, efficient and systematic access to diverse collections of macrocycles has proven difficult using classical macrocyclization reactions. To address this problem, we have developed a concise, modular approach to th...

The nature of bonding interactions between Fe(III) and NO in the ferric nitrosyl complexes of myoglobin (Mb), hemoglobin A (HbA), and horseradish peroxidase (HRP) is investigated by Soret-excited resonance Raman spectroscopy. On the basis of 15NO and N18O isotope shifts, we clearly identified the Fe(III)--NO bond stretching frequencies at 595 cm-1 (ferric Mb X NO), 594 cm-1 (ferric HbA X NO), a...

The important question of iron bioavailability in the sea has become complicated by the discovery that marine phytoplankton can take up Fe bound in very stable chelates via reductive processes, and some particular Fe species through specialized transport mechanisms. As a result there is some question of whether the small fraction of Fe that is ‘‘free’’ or unchelated in seawater is important in ...

This paper evaluates the degradation of two azo reactive dyes, C.I. Reactive Yellow 84 (RY84) and C.I. Reactive Red 120 (RR120) by photo-Fenton and Fenton-like oxidation. All experiments were performed on a laboratory scale set-up. The effects of different reaction parameters such as initial pH, contact time, effect of light and hydrogen peroxide concentrations on the oxidation of the dye aqueo...

Iron in the brain is utilized for cellular respiration, neurotransmitter synthesis/degradation, and myelin formation. Iron, especially its ferrous form, also has the potential for catalyzing the Fenton reaction to generate highly cytotoxic hydroxyl radicals. The amount of iron in the brain must therefore be strictly controlled. In this study, we focused on the cellular and subcellular localizat...

achillea tenuifolia lam. (asteraceae) afforded a dichloromethane fraction from which three known compounds β-sitosterol (compound1), 5-hydroxy, 4',6,7– trimethoxy flavone (salvigenin compound 2), and methyl-gallate (compound 3) were isolated for the first time. the structure of isolated compounds was elucidated by different spectroscopic methods. applying the molar-ratio method, the comple...

The paper describes a study of Fe(II) oxidation and the formation of Fe(III)-apoferritin complexes in recombinant human H-chain ferritin and its variants. The effects of site-directed changes in the conserved residues associated with a proposed ferroxidase centre have been investigated. A change in any of these residues is shown to reduce the rate of Fe(II) oxidation, confirming the importance ...