Structural Chemistry

, Volume 18, Issue 6, pp 833–839 | Cite as

Borazine: to be or not to be aromatic

  • Rafael Islas
  • Eduardo Chamorro
  • Juvencio Robles
  • Thomas Heine
  • Juan C. Santos
  • Gabriel MerinoEmail author
Original Paper


Aromaticity of borazine, which has been subject of controversial discussions, is addressed. Beside a short review on aromaticity of borazine we report a detailed analysis of two molecular fields, the induced magnetic field (B ind) and the electron localization function (ELF). The induced magnetic field of borazine shows a long-range shielding cone perpendicular to the molecular plane, as in benzene, but lower in magnitude. Contrary to benzene, borazine shows two weakly paratropic regions, one of them inside the ring, and the second one enveloping the boron atoms. It is necessary to separate σ and π contributions to identify whether borazine exhibits π-aromatic character comparable to benzene. Nucleus-independent chemical shift (NICS) isolines show that the σ electrons are much stronger localized than π electrons, their local paramagnetic contributions generate a short-range response and a paratropic (deshielding) region in the ring center (similar to an anti-aromatic response). Three regions can be identified as chemically meaningful domains exhibiting an internally strong electron delocalization (ELF = 0.823). Borazine may be described as a π aromatic compound, but it is not a globally aromatic species, as the electronic system is not as delocalized as in benzene.


Aromaticity Borazine ELF NICS Induced Magnetic Field 



This work was funded in part by grants from DINPO-UGTO, and the Deutsche Forschungsgemeinschaft (DFG). RI gratefully acknowledges a Conacyt Ph.D. fellowship. JCS and EC thank Fondecyt (Chile), grants 11060197 and 1070378, and the Millennium Nucleus for Applied Quantum Mechanics and Computational Chemistry (Mideplan-Conicyt, Chile), grant P02-004-F for continuous support. JCS and EC also thank to UNAB by support through the DI 22-05/R and 21-06/R research grants.


  1. 1.
    Stock A, Pohland E (1926) Chem Ber 59B:2215Google Scholar
  2. 2.
    In this molecule, the B-N bond length is intermediate between single and double bond B–N lengths. In borazines, B-N distances are in the range of 1.42–1.44 ÅGoogle Scholar
  3. 3.
    Wiberg E (1948) Natunviss 35:182Google Scholar
  4. 4.
    Chiavarino B, Crestoni ME, Fornarini S (1999) J Am Chem Soc 121:2619CrossRefGoogle Scholar
  5. 5.
    Chiavarino B, Crestoni ME, Di Marzio A, Fornarini S, Rosi M (1999) J Am Chem Soc 121:11204CrossRefGoogle Scholar
  6. 6.
    Kiran B, Phukan AK, Jemmis ED (2001) Inorg Chem 40:3615CrossRefGoogle Scholar
  7. 7.
    Timoshkin AY, Frenking G (2003) Inorg Chem 42:60CrossRefGoogle Scholar
  8. 8.
    Cyranski MK (2005) Chem Rev 105:3773CrossRefGoogle Scholar
  9. 9.
    Schleyer PvR, Puhlhofer F (2002) Org Lett 4:2873CrossRefGoogle Scholar
  10. 10.
    Fink WH, Richards JC (1991) J Am Chem Soc 113:3393CrossRefGoogle Scholar
  11. 11.
    Schleyer PV, Jiao HJ, Hommes N, Malkin VG, Malkina OL (1997) J Am Chem Soc 119:12669CrossRefGoogle Scholar
  12. 12.
    Benker D, Klapotke TM, Kuhn G, Li JB, Miller C (2005) Heteroatom Chem 16:311CrossRefGoogle Scholar
  13. 13.
    Fernandez I, Frenking G (2007) Faraday Discuss 135:403CrossRefGoogle Scholar
  14. 14.
    Fowler PW, Steiner E (1997) J Phys Chem A 101:1409CrossRefGoogle Scholar
  15. 15.
    Jemmis ED, Kiran B (1998) Inorg Chem 37:2110CrossRefGoogle Scholar
  16. 16.
    Schleyer PV, Jiao HJ (1996) Pure Appl Chem 68:209CrossRefGoogle Scholar
  17. 17.
    Steiner E, Soncini A, Fowler PW (2006) J Phys Chem A 110:12882CrossRefGoogle Scholar
  18. 18.
    Soncini A, Fowler PW, Lazzeretti P, Zanasi R (2005) Chem Phys Lett 401:164CrossRefGoogle Scholar
  19. 19.
    Boyd RJ, Choi SC, Hale CC (1984) Chem Phys Lett 112:136CrossRefGoogle Scholar
  20. 20.
    Jug K (1983) J Org Chem 48:1344CrossRefGoogle Scholar
  21. 21.
    Madura ID, Krygowski TM, Cyranski MK (1998) Tetrahedron 54:14913CrossRefGoogle Scholar
  22. 22.
    Phukan AK, Kalagi RP, Gadre SR, Jemmis ED (2004) Inorg Chem 43:5824CrossRefGoogle Scholar
  23. 23.
    Merino G, Heine T, Seifert G (2004) Chem Eur J 10:4367CrossRefGoogle Scholar
  24. 24.
    Becke AD, Edgecombe KE (1990) J Chem Phys 92:5397CrossRefGoogle Scholar
  25. 25.
    Heine T, Islas R, Merino G (2007) J Comput Chem 28:302CrossRefGoogle Scholar
  26. 26.
    Santos JC, Tiznado W, Contreras R, Fuentealba P (2004) J Chem Phys 120:1670CrossRefGoogle Scholar
  27. 27.
    Merino G, Vela A, Heine T (2005) Chem Rev 105:3812CrossRefGoogle Scholar
  28. 28.
    Poater J, Duran M, Sola M, Silvi B (2005) Chem Rev 105:3911CrossRefGoogle Scholar
  29. 29.
    Becke AD (1993) J Chem Phys 98:5648CrossRefGoogle Scholar
  30. 30.
    Lee CT, Yang WT, Parr RG (1988) Phys Rev B 37:785CrossRefGoogle Scholar
  31. 31.
    Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Zakrzewski VG, Montgomery JA, Stratmann RE, Burant JC, Dapprich S, Millan JM, Daniels AD, Kudin KN, Strain MC, Farkas O, Tomasi J, Barone V, Cossi M, Cammi R, Mennucci B, Pomelli C, Adamo C, Clifford S, Ochterski J, Petersson GA, Ayala PY, Cui Q, Morokuma K, Malick DK, Rabuck AD, Raghavachari K, Foresman JB, Cioslowski J, Ortiz JV, Baboul AG, Stefanov BB, Liu G, Liashenko A, Piskorz P, Komaromi I, Gomperts R, Martin RL, Fox DJ, Keith T, Al-Laham MA, Peng CY, Nanayakkara A, Gonzales C, Challacombe M, Gill PMW, Johnson B, Chen W, Wong MW, Andreas JL, Head-Gordon M, Reploge ES, Pople JA (1998) Gaussian 98, Gaussian 98 revision A7, Gaussian Inc, Pittsburg, PA, 1998Google Scholar
  32. 32.
    Krishnan R, Binkley JS, Seeger R, Pople JA (1980) J Chem Phys 72:650CrossRefGoogle Scholar
  33. 33.
    Kutzelnigg W, Fleischer U, Schindler M (1990) The IGLO-method: ab initio calculation and interpretation of NMR chemical shifts and magnetic susceptibilities, vol 23. Springer-Verlag, HeidelbergGoogle Scholar
  34. 34.
    Kutzelnigg W (1980) Isr J Chem 19:193Google Scholar
  35. 35.
    Koster AM, Flores R, Geudtner G, Goursot A, Heine T, Patchkovskii S, Reveles JU, Vela A, Salahub DR, demon (2004) NRC, CanadaGoogle Scholar
  36. 36.
    Malkin VG, Malkina OL, Reviakine R, Schimmelpfennig B, Arbuznikov V, Kaupp M (2001) MAG-ReSpect 1.0, MAG-ReSpect 1.0Google Scholar
  37. 37.
    Pipek J, Mezey PG (1989) J Chem Phys 90:4916CrossRefGoogle Scholar
  38. 38.
    Schleyer PvR, Jiao HF, Hommes NJRV, Malkin VG, Malkina O (1997) J Am Chem Soc 119:12669CrossRefGoogle Scholar
  39. 39.
    Corminboeuf C, Heine T, Weber J (2003) Phys Chem Chem Phys 5:246CrossRefGoogle Scholar
  40. 40.
    Heine T, Schleyer PvR, Corminboeuf C, Seifert G, Reviakine R, Weber J (2003) J Phys Chem A 107:6470CrossRefGoogle Scholar
  41. 41.
    Ozell B, Camarero R, Garon A, Guibault F (1995) Finite Elements Design 19:295CrossRefGoogle Scholar
  42. 42.
    Noury S, Krokidis X, Fuster F, Silvi B (1997) TopMoD package. Universite Pierre et Marie Curie, ParisGoogle Scholar
  43. 43.
    Portmann S, Luthi HP (2000) Chimia 54: 766Google Scholar
  44. 44.
    Merino G, Mendez-Rojas MA, Beltran HI, Corminboeuf C, Heine T, Vela A (2004) J Am Chem Soc 126:16160CrossRefGoogle Scholar
  45. 45.
    Perez N, Heine T, Barthel R, Seifert G, Vela A, Mendez-Rojas MA, Merino G (2005) Organ Lett 7:1509CrossRefGoogle Scholar
  46. 46.
    Islas R, Heine T, Merino G (2007) J Chem Theory Comput 3:775CrossRefGoogle Scholar
  47. 47.
    Savin A, Becke AD, Flad J, Nesper R, Preuss H, Vonschnering HG (1991) Angew Chem-Int Edit Engl 30:409CrossRefGoogle Scholar
  48. 48.
    Savin A, Nesper R, Wengert S, Fassler TF (1997) Angew Chem-Int Edit Engl 36:1809Google Scholar
  49. 49.
    Silvi B, Savin A (1994) Nature 371:683CrossRefGoogle Scholar
  50. 50.
    Fuentealba P, Chamorro E, Santos JC (2007) In: Toro-Labbe A (ed) Theoretical Aspects of Chemical Reactivity, vol 19. Elsevier, Amsterdam, p 57Google Scholar
  51. 51.
    Chesnut DB, Bartolotti LJ (2000) Chem Phys 257:175CrossRefGoogle Scholar
  52. 52.
    Fuster F, Sevin A, Silvi B (2000) J Phys Chem A 104:852CrossRefGoogle Scholar
  53. 53.
    Cardenas C, Chamorro E, Notario R (2005) J Phys Chem A 109:4352CrossRefGoogle Scholar
  54. 54.
    Chamorro EE, Notario R (2004) J Phys Chem A 108:4099CrossRefGoogle Scholar
  55. 55.
    Chamorro E (2003) J Chem Phys 118:8687CrossRefGoogle Scholar
  56. 56.
    Melin J, Fuentealba P (2003) Int J Quantum Chem 92:381CrossRefGoogle Scholar
  57. 57.
    Santos JC, Andres J, Aizman A, Fuentealba P (2005) J Chem Theor Comput 1:83CrossRefGoogle Scholar
  58. 58.
    Heine T, Corminboeuf C, Grossmann G, Haeberlen U (2006) Angew Chem-Int Edit 45:7292CrossRefGoogle Scholar
  59. 59.
    Heine T, Zhechkov L, Seifert G (2004) Phys Chem Chem Phys 6:980CrossRefGoogle Scholar
  60. 60.
    Chen Z, Wannere CS, Corminboeuf C, Puchta R, Schleyer PvR (2005) Chem Rev 105:3842CrossRefGoogle Scholar
  61. 61.
    Pelloni S, Ligabue A, Lazzeretti P (2004) Organ Lett 6:4451CrossRefGoogle Scholar
  62. 62.
    Viglione RG, Zanasi R, Lazzeretti P (2004) Organ Lett 6:2265CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Rafael Islas
    • 1
  • Eduardo Chamorro
    • 2
  • Juvencio Robles
    • 1
  • Thomas Heine
    • 3
  • Juan C. Santos
    • 2
  • Gabriel Merino
    • 1
    Email author
  1. 1.Facultad de QuímicaUniversidad de GuanajuatoGuanajuatoMexico
  2. 2.Departamento de Ciencias Químicas, Facultad de Ecología y Recursos NaturalesUniversidad Andres BelloSantiagoChile
  3. 3.Institut für Physikalische Chemie und ElektrochemieTU DresdenDresdenGermany

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