Halodiazirines and halodiazo compounds: a computational study of their thermochemistry and isomerization reaction
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A computational study of the isomerization reaction of a series of halodiazirines to halodiazo compounds (cyclic to open-chain RXCN2 species) has been carried out in order to establish the effect of the substituent groups on the isomerization rates and to obtain computational evidence of reaction mechanisms. Fluorine and chlorine were present as the halogen (X) atom, and the groups R=H, CH3, C2H5, n-C3H7, i-C3H7, cyclo-C3H5, phenyl, OCH3 and OH were used. Thermochemical calculations and natural bond orbital analyses were carried out at the B3LYP/6-31+G(d,p) level of theory. The results allowed us to discuss a reaction mechanism that proceeds in two steps: The first is the extrusion of nitrogen and formation of a carbene through a cyclic transition state that promotes the simultaneous breaking of the two C–N bonds, and the second one is described as the rebounding between the carbene and one of the nitrogen atoms of molecular nitrogen, both formed in the first step. The enthalpies of formation of halodiazirines and halodiazoalkanes have been calculated at the G3 level of theory.
KeywordsHalodiazirines Diazo compounds Isomerization reaction Substituent effect Transition state
We thank the financial support of the Universidad Nacional de Colombia-Medellín through the convocatory “Apoyo a grupos de investigación Facultad de Ciencias” under the project number 201010015547.
- 1.Korneev SM (2011) Eur J Org Chem 6153-6175Google Scholar
- 7.Liu MTH (1987) Chemistry of Diazirines. CRC Press, Boca RatonGoogle Scholar
- 11.Frey HM, Stevens IDR (1962) J Chem Soc 3865–3867Google Scholar
- 14.Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Scalmani G, Barone V, Mennucci B, Petersson GA, Nakatsuji H, Caricato M, Li X, Hratchian HP, Izmaylov AF, Bloino J, Zheng G, Sonnenberg JL, Hada M, Ehara M, Toyota K, Fukuda R, Hasegawa J, Ishida M, Nakajima T, Honda Y, Kitao O, Nakai H, Vreven T, Montgomery Jr JA, Peralta JE, Ogliaro F, Bearpark M, Heyd JJ, Brothers E, Kudin KN, Staroverov VN, Kobayashi R, Normand J, Raghavachari K, Rendell A, Burant JC, Iyengar SS, Tomasi J, Cossi M, Rega N, Millam JM, Klene M, Knox JE, Cross JB, Bakken V, Adamo C, Jaramillo J, Gomperts R, Stratmann RE, Yazyev O, Austin AJ, Cammi R, Pomelli C, Ochterski JW, Martin RL, Morokuma K, Zakrzewski VG, Voth GA, Salvador P, Dannenberg JJ, Dapprich S, Daniels AD, Farkas O, Foresman JB, Ortiz JV, Cioslowski J, Fox DJ (2010) Gaussian 09, Revision B.01, Gaussian Inc., Wallingford CTGoogle Scholar
- 18.Reed AE, Weinhold FJ (1983) Chem Phys 78:4066–4073Google Scholar
- 21.Glendening ED, Reed AE, Carpenter JE, Weinhold F (1988) NBO version 3.1 Madison, WIGoogle Scholar
- 22.Glasstone S, Laidler K, Eyring H (1941) The theory of rate processes, 1st edn. McGraw Hill, New YorkGoogle Scholar
- 23.Benson SW (1969) The foundations of chemical kinetics. McGraw Hill, New YorkGoogle Scholar
- 26.Bridge MR, Frey HM, Liu MTH (1969) J Chem Soc A 91-94Google Scholar
- 27.Frey HM, Liu MTH (1970) J Chem Soc A 1916–1919Google Scholar
- 37.Cadman P, Engelbrecht WJ, Lotz S, Van der Merwe SWJ (1974) J S Af Chem Inst 27:149–161Google Scholar