April 2010

Headline News Innovation and Development

Applied Technology

Basic Science Cooperation between CAS and Local Authorities
Bioscience International Cooperation Brief News Geoscience  
Basic Science

New Organic Semiconductor Materials Patented

Researchers from the Laboratory of Material Chemistry, Shanghai Institute of Organic Chemistry, CAS have developed a new class of solution-processable n-type organic semiconductors based on core-expanded naphthalene diimides fused with 2-(1,3-dithiol-2-ylidene) malonitrile groups (see Figure 1, R is long branched alkyl), through fusing electron-deficient aromatic nuclear with electron-rich sulfur-containing heterocyclic compounds (to improve the mobility) and using electron-withdrawing malonitrile end-group (to improve the stability). Though cooperation with researchers from the Key Laboratory of Organic Solids, Institute of Chemistry, CAS, they successfully fabricated the OTFT (organic thin film transistor) devices of this class of molecular material by means of solution processing. The devices exhibit high electron mobility of up to 0.51 cm2V-1s-1, with current on/off ratios of 105 and threshold voltages below 10V. Moreover, they have excellent air and operating stability. The devices have best mobility and stability among solution-processable n-type organic micro-molecular materials reported so far. A Chinese patent has been applied for relevant work, some results of which were published by the Journal of the American Chemical SocietyJ. Am. Chem. Soc. 2010, 132, 3697-3699).

Series Progress in Fullerene Derivatives Research

Exohedral functionalization of fullerenes and metal fullerenes to regular the electronic structure and performance of this type functional molecules is one of key research fields in fullerene chemistry. Recently, researchers from the Key Lab of Molecular Nanostructure & Nanotechnology, CAS, through cooperation with scientists from the Xiamen University, achieved series of new research results in the derivatization of fullerenes and endohedral metallofullerenes. For the functionalization of endohedra fullerenes, researchers selected a kind of carbide endohedral metallofullerene Sc3C2@C80 to carry out exohedral functionalization. This is a molecule with novel paramagnetism. It has an unpaired electron distributed at the endohedral Sc3C2 cluster. They found that Sc3C2 cluster rotated freely at high speed before chemical reaction due to high symmetry (Ih) of C80 cage, resulting in identical chemical environment of three Scandium (Sc) ions and formation of a twin-conical structure with D3h symmetry between those three Sc ions and C2. If a pyrrolidine group was added to C80 cage through chemical reaction, the electric field distribution inside C80 would be sure to lose homogeneity when the high symmetry of fullerene cage was broken, which greatly limited the movement of Sc3C2 cluster. This directly resulted in decrease of the symmetry of Sc3C2 cluster from D3h to C2v and strongly affected its electronic properties due to the alteration of its molecular structure. Significant change of its paramagnetism before and after chemical reaction was clearly observed in the experiment (Angew. Chem., Int. Ed. 2010, 49, 1786–1789). This approach of altering the structure of endohedral Sc3C2 cluster and then regulating the molecular magnetism through exohedral functionalization provides foundation for the construction of fullerene molecular device and fullerene-based quantum computer research. Relevant research results were published in Angew. Chem., Int. Ed. 2010, 49, 962-966 and Angew. Chem., Int. Ed. 2010, 49, 1786 –1789 and highlighted in the Nature China.

Other Issues
Sixty-eighth Issue (February 2010)

Sixty-seventh Issue (December 2010)

Sixty-sixth Issue (October 2009)
Sixty-fifth Issue (August 2009)
Sixty-fourth Issue (June 2009)
Sixty-third Issue (April 2009)
Sixty-second Issue (February 2009)
Sixty-first Issue (December 2008)
Sixtieth Issue (October 2008)
Fifty-nineth Issue (August 2008)
Fifty-eighth Issue (June 2008)
Fifty-seventh Issue (April 2008)
Fifty-sixth Issue (February 2008)
Fifty-fifth Issue (December 2007)
Fifty-fourth Issue (October 2007)
Fifty-third Issue (August 2007)
Fifty-second Issue (June 2007)
Fifty-first Issue (April 2007)
Fiftith Issue (Feb. 2007)
Fourty-nineth Issue (December, 2006)
Fourty-eighth Issue (Ocboter, 2006)
Fourty-seventh Issue (August, 2006)
Fourty-sixth Issue (June, 2006)
Fourty-fifth Issue (April, 2006)
Fourty-fourth Issue (February, 2006)
Fourty-third Issue (December, 2005)
Fourty-second Issue (October, 2005)
Fourty-first Issue (August, 2005)
Fourtith Issue (June, 2005)
Thirty-ninth Issue (April, 2005)
Thirty-eighth Issue (February, 2005)
Thirty-seventh Issue (December, 2004)
Thirty-sixth Issue (October, 2004)
Thirty-fifth Issue (August, 2004)
Thirty-fourth Issue (June, 2004)
Thirty-third Issue (April, 2004)
Thirty-second Issue (February, 2004)
Thirty-first Issue (December, 2003)
Thirtieth Issue (October, 2003)
Twenty-nineth Issue (August, 2003)
Twenty-eighth Issue (June, 2003)
Twenty-seventh Issue (Spring, 2003)

copyright © 1998-2010
CAS Newsletter Editorial Board: 52, Sanlihe Road, Beijing 100864, CHINA