Chemistry:Planar hexacoordinate carbon

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Planar hexacoordinate carbon

Planar hexacoordinate carbon in chemistry describes a molecular geometry featuring a planar arrangement of carbon with six surrounding atoms. No actual chemical compounds having this particular hexacoordinate configuration have been reported but quantum mechanical methods have demonstrated that these molecules are a possibility.[1][2][3] Examples of molecules investigated with computational methods are the B6C dianion,[2][4] the CN3Be3+ ion, the CO3Li3+ ion[5] and the CN3Mg3+ ion.[6] A simulated Be2C monolayer is reported to consist of quasi-planar hexacoordinate carbon atoms.[7]

On the other hand, experimental research has confirmed that the pentagonal-pyramidal hexamethylbenzene ion, C6(CH3)62+, contains a hexacoordinate carbon atom.[8] Furthermore, a heptacoordinate carbon atom has been predicted to be involved in a stable hexagonal-pyramidal configuration of tropylium trication, (C7H7)3+.[9]

References

  1. Aromaticity and Metal Clusters Pratim Kumar Chattaraj October 15, 2010 by CRC Press ISBN:9781439813355
  2. 2.0 2.1 Planar Hexacoordinate Carbon: A Viable Possibility Kai Exner, Paul von Ragué Schleyer Science 8 December 2000: Vol. 290 no. 5498 pp. 1937-1940 doi:10.1126/science.290.5498.1937
  3. Non-classical structures of organic compounds: unusual stereochemistry and hypercoordination V I Minkin, RMMinyaev, R Hoffmann Russian Chemical Reviews 71 (11) 869 ± 892 (2002) doi:10.1070/RC2002v071n11ABEH000729
  4. Myriad Planar Hexacoordinate Carbon Molecules Inviting Synthesis Keigo Ito, Zhongfang Chen, Clémence Corminboeuf, Chaitannya S. Wannere, Xiu Hui Zhang, Qian Shu Li, Paul v. R. Schleyer Journal of the American Chemical Society 2007 129 (6), 1510-1511 doi:10.1021/ja067292+
  5. D 3h CN3Be3+ and CO3Li3+: viable planar hexacoordinate carbon prototypes Yan-Bo Wu, Yan Duan, Gang Lu, Hai-Gang Lu, Pin Yang, Paul von Ragué Schleyer Gabriel Merino, Rafael Islasef and Zhi-Xiang Wang Phys. Chem. Chem. Phys., 2012,14, 14760-14763 doi:10.1039/C2CP41822C
  6. Thermodynamic Stability versus Kinetic Stability: Is the Planar Hexacoordinate Carbon Species D3h CN3Mg3+ Viable? Chao-Feng Zhang, Shao-Jin Han, Yan-Bo Wu, Hai-Gang Lu, and Gang Lu The Journal of Physical Chemistry A 2014 118 (18), 3319-3325 doi:10.1021/jp411400m
  7. Li, Y., Liao, Y. and Chen, Z. (2014), Be2C Monolayer with Quasi-Planar Hexacoordinate Carbons: A Global Minimum Structure. Angew. Chem. Int. Ed., 53: 7248–7252. doi:10.1002/anie.201403833
  8. Malischewski, Moritz; Seppelt, K. (2017-01-02). "Crystal Structure Determination of the Pentagonal-Pyramidal Hexamethylbenzene Dication C 6 (CH 3 ) 6 2+" (in en). Angewandte Chemie International Edition 56 (1): 368–370. doi:10.1002/anie.201608795. PMID 27885766. 
  9. Wang, George; Rahman, A. K. Fazlur; Wang, Bin (May 2018). "Ab initio calculations of ionic hydrocarbon compounds with heptacoordinate carbon" (in en). Journal of Molecular Modeling 24 (5): 116. doi:10.1007/s00894-018-3640-9. ISSN 1610-2940. PMID 29696384.