Cover Picture: Asararenes—A Family of Large Aromatic Macrocycles (Chem. Eur. J. 12/2013)

Authors

  • Dr. Severin T. Schneebeli,

    1. Center for the Chemistry of Integrated Systems and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-311 (USA), Fax: (+1) 847-491-1009
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    • These authors contributed equally to this work.

  • Chuyang Cheng,

    1. Center for the Chemistry of Integrated Systems and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-311 (USA), Fax: (+1) 847-491-1009
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    • These authors contributed equally to this work.

  • Dr. Karel J. Hartlieb,

    1. Center for the Chemistry of Integrated Systems and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-311 (USA), Fax: (+1) 847-491-1009
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  • Nathan L. Strutt,

    1. Center for the Chemistry of Integrated Systems and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-311 (USA), Fax: (+1) 847-491-1009
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  • Dr. Amy A. Sarjeant,

    1. Center for the Chemistry of Integrated Systems and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-311 (USA), Fax: (+1) 847-491-1009
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  • Dr. Charlotte L. Stern,

    1. Center for the Chemistry of Integrated Systems and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-311 (USA), Fax: (+1) 847-491-1009
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  • Prof. J. Fraser Stoddart

    Corresponding author
    1. Center for the Chemistry of Integrated Systems and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-311 (USA), Fax: (+1) 847-491-1009
    • Center for the Chemistry of Integrated Systems and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-311 (USA), Fax: (+1) 847-491-1009
    Search for more papers by this author

Abstract

original image

A component of ginger namely, 1,2,4,5-tetramethoxybenzene, when heated in 1,2-dichloroethane, along with paraformaldehyde in the presence of boron trifluoride etherate, has spawned a new family of aromatic macrocycles, called asararenes. The cover image produced by Aleksandr Bosoy shows the X-ray superstructure of asar[10]arene. The individual macrocycles comprising this asararene stack to form cylindrical nanotube-like channels packed together in a regular checkerboard array. Just as cyclodextrins and cucurbiturils, for example, have become household names and major players in supramolecular chemistry, materials science and molecular nanotechnology, so could the asararenes in the fullness of time. For more details, see the Full Paper by J. F. Stoddart et al. on page 3860 ff.

Cartoon 1.

A component of ginger namely, 1,2,4,5-tetramethoxybenzene, when heated in 1,2-dichloroethane, along with paraformaldehyde in the presence of boron trifluoride etherate, has spawned a new family of aromatic macrocycles, called asararenes. The cover image produced by Aleksandr Bosoy shows the X-ray superstructure of asar[10]arene. The individual macrocycles comprising this asararene stack to form cylindrical nanotube-like channels packed together in a regular checkerboard array. Just as cyclodextrins and cucurbiturils, for example, have become household names and major players in supramolecular chemistry, materials science and molecular nanotechnology, so could the asararenes in the fullness of time. For more details, see the Full Paper by J. F. Stoddart et al. on page 3860 ff.

Nanomedicine

The extracellular landscape of cell surfaces is coated with carbohydrates that bind proteins as well as proteins that recognize and bind specific carbohydrates. Structured nanomaterials have proven useful in understanding the importance of these interactions and how they contribute to cellular function. Multivalent effects play an important role in these inherently weak interactions and thus their impact on nanostructured materials is rapidly enhancing this field of study. In the Concept Article on page 3794 ff., P. H. Seeberger et al. highlight novel materials that have been developed to image cellular structures as well as to detect biomarkers.

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Total Synthesis

In their Communication on page 3802 ff. N. Kumagai, M. Shibasaki et al. describe an efficient enantioselective synthetic route to atorvastatin based on a direct catalytic asymmetric aldol reaction. In contrast to the first-generation synthetic route, the expensive chiral ligand used in the initial aldol reaction was readily recovered (91%). Furthermore, the nitrogen atom of a thioamide could be retained in the final product, reducing the number of requisite synthetic steps. Implementation of an oxy-Michael reaction for the construction of the syn-1,3-diol unit also eliminated several redundant steps, allowing for rapid access to the common intermediate.

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Heterogeneous Catalysis

The active sites in fluid catalytic cracking (FCC) particles, employed in the oil industry, can be selectively stained with a probe that forms fluorescent products at the Brønsted acid sites of the catalyst. Samples taken from a commercial FCC cracking unit, ECat samples, were imaged with an integrated laser and electron microscope (iLEM). An iLEM uniquely combines a fluorescence and a transmission electron microscope within a single set-up, thus allowing the correlation of Brønsted acidity to the structure of the catalyst particles. Using this approach, B. M. Weckhuysen et al. have identified various structural defects in the ECat samples and postulated a model for the degradation of the FCC particles while cycling through the FCC unit. For more information see the Full Paper on page 3846 ff.

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Ancillary