Angewandte Chemie International Edition

Herrmann, Andreas

doi: 10.1002/anie.200790150pmid: N/A

Scents emitted from flowers are highly volatile and can only be perceived for a limited period of time. To control their longevity in everyday perfumed products, they either can be encapsulated as the floral accord, as on the front cover, or released by chemical bond cleavage from pro‐perfumes, as described in the Review by A. Herrmann on page 5836 ff. The floral accord was composed by Johannes Feser (Firmenich SA) and is based on hedione HC, helional, and hexenyl salicylate.

Mir, Mohammad Hedayetullah; Vittal, Jagadese J.

doi: 10.1002/anie.200790151pmid: N/A

The structures of water that are so far known may be just the tip of the iceberg. In their Communication on page 5925 ff., Mir and Vittal describe a discrete cyclic water heptamer trapped inside a 3D coordination polymer. When the single crystal is cooled from 296 K to 223 K, it undergoes a phase transition with structural transformation to a bicyclic water heptamer containing edge‐sharing pentamer and tetramer rings. The background shows the iceberg of Possession Bay, taken with permission from http://www.sgisland.org.

doi: 10.1002/anie.200790152pmid: N/A

doi: 10.1002/anie.200790153pmid: N/A

doi: 10.1002/anie.200702892pmid: N/A

Cornils, Boy

doi: 10.1002/anie.200785509pmid: N/A

Schmuck, Carsten

doi: 10.1002/anie.200702125pmid: 17614344

Molecular hospitality: Self‐assembled molecular containers provide a very specific geometric as well as chemical environment for a bound guest, which allows for selective guest binding or the stabilization of unstable molecules or unstable conformations within the capsule (see scheme). The geometric constraints imposed by the container can even change the outcome of a chemical reaction.

Herrmann, Andreas

doi: 10.1002/anie.200700264pmid: 17605134

Volatile organic compounds serve in nature as semiochemicals for communication between species, and are often used as flavors and fragrances in our everyday life. The quite limited longevity of olfactive perception has led to the development of pro‐perfumes or pro‐fragrances—ideally nonvolatile and odorless fragrance precursors which release the active volatiles by bond cleavage. Only a limited amount of reaction conditions, such as hydrolysis, temperature changes, as well as the action of light, oxygen, enzymes, or microorganisms, can be used to liberate the many different chemical functionalities. This Review describes the controlled chemical release of fragrances and discusses additional challenges such as precursor stability during product storage as well as some aspects concerning toxicity and biodegradability. As the same systems can be applied in different areas of research, the scope of this Review covers fragrance delivery as well as the controlled release of volatiles in general.

Dauenhauer, Paul J.; Dreyer, Bradon J.; Degenstein, Nick J.; Schmidt, Lanny D.

doi: 10.1002/anie.200701238pmid: 17610233

Breaking the coke habit: By coupling thermal decomposition with catalytic partial oxidation, an effective method has been developed to convert solid biomass such as cellulose into synthesis gas (see photo of a hot Rh catalyst surface). Not only is the process fast (<70 ms), it also avoids the formation of coke, which is known to deactivate catalyst surface sites and block surface reactions.

Jeong, Nak Cheon; Lee, Myoung Hee; Yoon, Kyung Byung

doi: 10.1002/anie.200701676pmid: 17607674

Mind the gap! The titanosilicate zeolite ETS‐10 contains TiO32− molecular wires (see picture). A reliable method has been developed to synthesize high‐quality ETS‐10 crystals of various sizes. Measurements on the crystals allow the dependence of the band‐gap energy on the length of the TiO32− wires to be elucidated.