An octadentate cyclen-based europium complex with amidic and hydroxyalkyl pendent moieties exhibits pH dependent ligand denticity associated with anion recognition. Unusually high hydration numbers are determined for ortho-phthalate ternary outer-sphere complexes for which modulation of lanthanide-based luminescence is observed.

The catalytic, enantioselective, [4 + 2] cycloaddition reaction of ortho-quinone methides with silyl ketene acetals is described. This mechanistically interesting reaction, initiated by a chiral cinchona alkaloid-derived ammonium fluoride "precatalyst" complex, affords a variety of alkyl- and aryl-substituted 3,4-dihydrocoumarin products in excellent yield and with good enantioselectivity.

PURPOSE Myopia is a common ocular disorder, and progression of myopia in children is of increasing concern. Modern overnight orthokeratology (ortho-k) is effective for myopic reduction and has been claimed to be effective in slowing the progression of myopia (myopic control) in children, although scientific evidence for this has been lacking. This 2 year pilot study was conducted to determine w...

The cationic Rh-SEGPHOS complex catalyzed an intermolecular [2 + 2 + 2] cycloaddition of enynes, possessing an ortho-substituted aryl group on their alkyne terminus, with acetylenedicarboxylates. Bicyclic cyclohexa-1,3-dienes with both central and axial chiralities were obtained in extremely highly diastereo- and enantioselective manner.

The new well-defined catalyst [Pd(μ-Cl)Cl(IPr*)]2 enables the efficient Grignard reagent cross-coupling for the synthesis of tetra-ortho-substituted biaryls. The high reactivity of the complex is associated with the important bulkiness of the IPr* ligand. The dimer represents the most efficient catalyst reported to date for this challenging transformation.

A review of selected literature data related to intramolecular hydrogen bonding in ortho-hydroxyaryl Schiff bases, ortho-hydroxyaryl ketones, ortho-hydroxyaryl amides, proton sponges and ortho-hydroxyaryl Mannich bases is presented. The paper reports on the application of experimental spectroscopic measurements (IR and NMR) and quantum-mechanical calculations for investigations of the proton tr...

A variety of ortho,ortho'-disubstituted hydrobenzoin derivatives are readily accessible through a directed ortho,ortho'-dimetalation strategy in which the alcohol functions in hydrobenzoin are deprotonated by n-BuLi and the resulting lithium benzyl alkoxides serve as directed metalation groups. The optimization and scope of this reaction are discussed, and the utility of this process is demonst...

Inelastic neutron scattering, far-infrared spectroscopy, and cryogenic nuclear magnetic resonance are used to investigate the quantized rotation and ortho-para conversion of single water molecules trapped inside closed fullerene cages. The existence of metastable ortho-water molecules is demonstrated, and the interconversion of ortho-and para-water spin isomers is tracked in real time. Our inve...

Caged non-ionic detergents, comprised of polar oligo(ethylene glycol) and non-polar alkyl chains joined by a photocleavable ortho-nitrobenzyl sulfonate linker have been synthesized and characterized. The light-triggered transformation of such chameleon surfactant from a charge-neutral into a charged form offers great potential to improve 2-D gel electrophoretic separation of complex protein mix...

The aim of this study was to determine the effects of subchronic exposure to complex mixtures of polyhalogenated aromatic hydrocarbons (PHAHs) on the thyroid hormone and retinoid status in female Sprague-Dawley rats and to investigate the predictability of these effects by the toxic equivalency factor (TEF) concept. In the first experiment, the focus was on a complex dioxin-like PHAH mixture, w...