Professor Chen's recent JACS paper on SiC2 silagraphene was highlighted by Nature China and the ACS website
Rule-breaking molecules gain us deeper chemical insights, and often lead to discoveries of exceptional materials with novel properties. One example is the planar tetracoordinate carbon. The spatial tetrahedral coordination of saturated carbon was revealed independently by vanâ€™t Hoff and Le Bel more than a century ago, and is a textbook concept. However, the planar tetracoordinate carbon does exist in many crystal structures and in hundreds of predicted molecules.
Together with his collaborator, Professor Zhen Zhou and Yafei Li at Nankai University, Professor Chen and his student Fengyu Li extended the planar tetracoordinate carbon to the heavier analogue, silicon, and presents the systematic theoretical study on the first anti-vanâ€™t Hoff/Lebel species in the Si-containing extended systems.
Besides the unique bonding character, the systems predicted, namely SiC2 graphene, nanotubes and nanoribbons, have rather exceptional properties which hold great promise for many applications. For example, in contrast to their carbon and SiC analogues, all these Si-containing nanomaterials are metallic, SiC2 nanotubes have excellent elastic properties.
For details of this paper, please refer to
Yafei Li, Fengyu Li, Zhen Zhou, and Zhongfang Chen J. Am. Chem. Soc., 2011, 133 (4), pp 900â€“908
Publication Date (Web): December 23, 2010 (Article) DOI: 10.1021/ja107711m
Below is the highlight by Nature China
Theoretical chemistry:Â Flattening silicon
Graphene is a remarkable material with an array of unusual properties that make it highly attractive for applications ranging from electronics to bioengineering. The graphene structure is known as planar tricoordinate â€” a hexagonal network of carbon atoms in a two-dimensional sheet that can be rolled up to form nanotubes or sliced to form ribbons. Zhen Zhou at Nankai University in Tianjin, China, Zhongfang Chen at the University of Puerto Rico and co-workers have now performed simulations showing that it is also possible to construct a similar structure incorporating silicon, termed 'silagraphene', and that this structure has potentially useful properties1.
Â© (2010) ACS
Using density functional calculations, the researchers modelled the possible structural forms of SiC4 and found that one of the structures had a planar tetracoordinated silicon configuration. From that structure, they designed SiC2 â€” silagraphene (pictured) â€” in which each silicon atom is bonded to four carbon atoms to form a two-dimensional sheet.
The silagraphene sheet structure is predicted to be stable and feasible to produce experimentally by methods such as chemical vapour deposition. Sheets of silagraphene can also be rolled into nanotubes or cut into nanoribbons that, unlike graphene, have metallic properties regardless of width or chirality.
The authors of this work are from:
Institute of New Energy Material Chemistry, Key Laboratory of Advanced Energy Materials Chemistry, Tianjin Key Laboratory of Metal and Molecule Based Material Chemistry, Nankai University, Tianjin, China; Department of Chemistry, Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico.
Li, Y., Li, F., Zhou, Z. & Chen, Z. SiC2 silagraphene and its one-dimensional derivatives: where planar tetracoordinate silicon happens. J. Am. Chem. Soc. doi:10.1021/ja107711m (2011).