Small-molecule-directed nanoparticle assembly towards stimuli-responsive nanocomposites

Nature Materials. doi:10.1038/nmat2565

Authors: Yue Zhao, Kari Thorkelsson, Alexander J. Mastroianni, Thomas Schilling, Joseph M. Luther, Benjamin J. Rancatore, Kazuyuki Matsunaga, Hiroshi Jinnai, Yue Wu, Daniel Poulsen, Jean M. J. Fréchet, A. Paul Alivisatos & Ting Xu

Organization of phosphorescent domains in seld-assembled block copolymers is demonstrated to yield dual emission for white electroluminescence. Our block- copolymer approach minimizes energy transfer between two colored species by site isolation through morphology control, allowing higher loading concentration of red emitters with improved device performance.

[Communication]
Daniel A. Poulsen, Bumjoon J. Kim, Biwu Ma, C. Sebastian Zonte, Jean M. J. Fréchet
Adv. Mater., September 3, 2009, DOI: 10.1002/adma.200901453. Read article.

A crossing between phases: Polarity makes a difference in distinguishing substrates of otherwise nearly identical chemical reactivities. A one-pot cascade reaction involving nitromethane and two aliphatic aldehydes with similar reactivities has been developed (see scheme). The use of a biphasic reaction medium with two different organic catalysts results in the controlled incorporation of both aldehyde substrates into a single major cross-product.

[Communication]
Steven T. Scroggins, Yonggui Chi, Jean M. J. Fréchet
Angew. Chem. Int. Ed., August 17, 2009, DOI: 10.1002/anie.200902945. Read article.

Steven T. Scroggins, Yonggui Chi, and Jean M. J. Fréchet*

The concept of using polarity differences to direct reactions is demonstrated in a novel one-pot cascade sequence of condensation followed by conjugate addition. The two-step reaction incorporates nitromethane and two aliphatic aldehydes with similar chemical reactivities. Under typical homogeneous conditions either aldehyde can be incorporated at each step of the reaction, and a statistical mixture is formed of four equally favored products. In contrast, the use of a biphasic reaction medium with two different organic catalysts results in the selective incorporation of both aldehydes with a strong preference for a major "cross" product.

Received June 02, 2009, published online August 17, 2009, DOI: 10.1002/anie.200902945.

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