Taming the Reactivity of Alkyl Azides by Intramolecular Hydrogen Bonding: Site-Selective Conjugation of Unhindered Diazides

Organic azides are still in the center of click chemistry connecting two molecules. However, taming the conjugation selectivity of azides is difficult without the help of the bulky groups. We...

Self-assembly and phase behavior of mixed patchy colloids with any bonding site geometry: theory and simulation

Novel theory incorporating multibody correlations accurately predicts aggregation and phase behavior in mixed Janus, Saturn ring, and Ternary patchy colloids.

Photochemical Deracemization of Chiral Sulfoxides Catalyzed by a Hydrogen-Bonding Xanthone Sensitizer

Several chiral sulfoxides with a lactam hydrogen-bonding site were prepared and their photochemical behavior was studied in the presence of xanthone and thioxanthone sensitizers. While acyclic sulfoxides showed only decomposition, chiral benzothiazinone-1-oxides with a stereogenic sulfur atom underwent a stereomutation upon irradiation at λ = 366 nm in the presence of catalytic quantities of a xanthone sensitizer. A chiral xanthone with a 1,5,7-trimethyl-3-azabicyclo-[3.3.1]nonan-2-one backbone was employed in catalytic quantities (5 mol%) to achieve a deracemization reaction of racemic benzothiazinone-1-oxides in acetonitrile solution. Five substrates could be successfully deracemized in good yields and with up to 55% ee.

Site-selective nitrenoid insertions utilizing postfunctionalized bifunctional rhodium(ii) catalysts

Site-selective nitrenoid insertions are made possible with a postfunctionalized dirhodium(ii)-catalyst equipped with a remote hydrogen bonding site.

Strength of silk attachment to Ilex chinensis leaves in the tea bagworm Eumeta minuscula (Lepidoptera, Psychidae)

Silks play an important role in the life of various arthropods. A highly neglected prerequisite to make versatile use of silks is sufficient attachment to substrates. Although there have been some studies on the structure and mechanics of silk anchorages of spiders, for insects only anecdotal reports on attachment-associated spinning behaviour exist. Here, we experimentally studied the silk attachment of the pupae and last instar caterpillars of the tea bagworm Eumeta minuscula (Butler 1881) (Lepidoptera, Psychidae) to the leaves of its host plant Ilex chinensis . We found that the bagworms spin attachment discs, which share some structural features with those of spiders, like a plaque consisting of numerous overlaid, looped glue-coated silk fibres and the medially attaching suspension thread. Although the glue, which coats the fibres, cannot spread and adhere very well to the leaf surface, high pull-off forces were measured, yielding a mean safety factor (force divided by the animal weight) of 385.6. Presumably, the bagworms achieve this by removal of the leaf epidermis prior to silk attachment, which exposes the underlying tissue that represents a much better bonding site. This ensures a reliable attachment during the immobile, vulnerable pupal stage. This is the first study on the biomechanics and structure of silk attachments to substrates in insects.