Cover Picture: Synthesis and Structure of Tetraarylcumulenes: Characterization of Bond-Length Alternation versus Molecule Length (Angew. Chem. Int. Ed. 6/2013)



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sp-Hybridized carbon allotropes based on a polyyne framework are well documented, while properties of the cumulenic form of these allotropes remain mysterious. In their Communication on page 1817 ff., R. R. Tykwinski and co-workers shed new light on the properties of cumulenes (such as bond length alternation) through the synthesis, spectroscopic study, and crystallographic analysis of cumulenes that contain up to nine consecutive double bonds (i.e., a [9]cumulene). Cover art: Annie Tykwinski; based on a concept from D. Wendinger.

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Conducting Materials

In their Communication on page 1654 ff., S. H. Yu and co-workers detail a new type of stretchable conductor based on a binary structure design, which enhances the electronic performance and electromechanical stability of the material.

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Geodesic Polyarenes

In their Communication on page 1713 ff. D. Myśliwiec and M. Stępień describe the synthesis of chrysaorole. This strained system was obtained from a carbazole-based macrocyclic precursor by using a new “fold-in” strategy.

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Main Group Chemistry

An air-stable silicon biradical was synthesized from a silicon(II) precursor. In their Communication on page 1801 ff., H. W. Roesky, I. Tkach, D. Stalke et al. observed a C[BOND]C bond formation during the reaction at room temperature.

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