Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (09): 1847-1852.doi: 10.3866/PKU.WHXB20090912

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Unusual Boron-Carbon Compounds Containing Planar Tetracoordinate and Pentacoordinate Carbons

LIANG Jing-Xia, JIA Wen-Hong, ZHANG Cong-Jie, CAO Ze-Xing   

  1. Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry &Materials Science, Shaanxi Normal University, Xi'an 710062, P. R. China|State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry| Xiamen University, Xiamen 361005, Fujian Province, P. R. China
  • Received:2009-04-15 Revised:2009-05-20 Published:2009-09-03
  • Contact: ZHANG Cong-Jie E-mail:zcjwh@snnu.edu.cn

Abstract:

Unusual boron-carbon compounds containing planar tetracoordinate carbon (ptC) and planar pentacoordinate carbon (ppC) were investigated using density functional theory (DFT) at B3LYP/6-311+G**level. These novel compounds are generally assembled with three types of stable structural units C3B2H4 with ptC, CB4H2 with ptC, and CB5H2 with ppC as well as linking elements —CHCH—. On the basis of calculation results the bonding features, spectroscopic properties, and the aromaticities of these novel boron-carbon compounds were discussed. Results show that as for the lowest-energy compounds contained ptC and ppC without being limited by symmetrical planes, stereo cis-structures of C2v symmetry are more stable than the corresponding planar trans-structures. Calculated nucleus- independent chemical shift (NICS) values show that the aromaticity of the center of the three-membered rings is the strongest. The total Wiberg bond indices (WBIs) of the ptC and ppC atoms of the most stable structures of the boron-carbon compounds indicate that the ptC and ppC obey the octal rule.

Key words: Density functional theory, Planar tetracoordinate carbon, Planar pentacoordinate carbon, Aromaticity

MSC2000: 

  • O641