7
30
Y.S. Mary et al. / Spectrochimica Acta Part A 71 (2008) 725–730
and 181 cm 1. In 2-chloropyrazine the in-plane andout-of-plane
−
[
4] M.C. Raviglione, C. Dye, S. Smidt, A. Kochi, Lancet. 35 (1997) 624.
−
1
[5] S. Houston, A. Fanny, Drugs 48 (1996) 689.
deformation modes of CCl are reported at 309 and 188 cm [1].
[
[
[
6] D.E. Snider, K.G. Castro, New Engl. J. Med. 338 (1998) 1689.
7] D.A. Mitchison, Natur. Med. 2 (1996) 6.
8] M.H. Cynamon, S.P. Klemens, T.S. Chou, R.H. Gimi, J.T. Welch, J. Med.
Chem. 35 (1992) 1212.
−
1
The ring breathing mode of pyrazine is reported at 1015 cm
1]. In the Raman spectrum of 2,6-dichloropyrazine and 2-
chloropyrazine the ring breathing mode is reported at 1131 and
049 cm [1]. We have observed the ring breathing mode at
016 cm in the IR spectrum and 1013 cm theoretically.
Table 1 lists the optimized geometries calculated for free
molecule of the title compound. For 2-aminopyrazine-3-
carboxylic acid [3,29] the bond lengths C –C10, C10 O23,
C –N and C –C4 are 1.479, 1.212, 1.333, 1.479 A (exper-
imental values) and 1.492, 1.186, 1.315, 1.492 A (ab initio
calculations), respectively. In the present case, the correspond-
ing values are 1.5059, 1.2003, 1.3229 and 1.384 A, respectively.
For pyrazine ring [30] the C N and C–N bond lengths are 1.339
experimental), 1.331 A (DFT). For 2-chloropyrazine [1] C N
bond lengths are 1.335 (experimental), 1.334 A (DFT) and C–N
bond lengths are 1.312 (experimental), 1.325 A (DFT). We have
calculated C N and C–N bond lengths as 1.3229, 1.3222 A
and 1.2996, 1.3116 A, respectively. The CCl bond length in
the present case is 1.7329 A which is in agreement with the
previous reported value [1]. The substitution of chlorine in the
pyrazine ring shortens the C1–N bond length and elongates the
C1–C2 bond length. Chlorine is highly electronegative and tries
to obtain additional electron density. It attempts to draw it from
the neighbouring atoms, which move closer together in order
to share the remaining electron more easily as a result. Due to
this the bond angle A(2,1,6) is found to be 122.3 and the exo-
cyclic angles A(6,1,7) and A(2,1,7) become 118.2 and 119.5 ,
respectively. At N22 position, the angles C10–N22–H24 is 111.7 ,
C11–N22–H24 is 116.7 and C10–N22–C11 is 128.6 . This asym-
metry of the angles at N22 position indicates the weakening of
N22–H24 bond resulting in proton transfer to the oxygen atom
O23 [22]. All the carbon–carbon bond lengths in the benzene
ring lie in the range 1.3823–1.3944 A and C–H bond lengths
in the range 1.0749–1.0756 A. Here for the title compound, the
benzene ring is a regular hexagon with bond length somewhere
in between the normal values for a single (1.54 A) and a double
1.33 A) bond [31].
[
−
1
[
9] K.E. Bergmann, M.H. Cynanon, J.T. Welch, J. Med. Chem. 39 (1996) 3394.
1
1
−
1
−1
[10] N.E. Good, Plant Physiol. 36 (1961) 788.
[
[
[
11] K. Kralova, F. Sersen, J. Cizmarik, Chem. Pap. 46 (1992) 266.
12] K. Kralova, F. Sersen, M. Miletin, J. Hartal, Chem. Pap. 52 (1998) 52.
13] K. Kralova, F. Sersen, L. Kubicova, K. Waisser, Chem. Pap. 53 (1999)
328.
5
˚
[14] M. Dolezal, M. Miletin, J. Kunes, K. Kralova, Molecules 7 (2002) 363.
5
6
5
[
15] M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R.
Cheeseman, J.A. Montgomery Jr., T. Vreven, K.N. Kudin, J.C. Burant, J.M.
Millam, S.S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scal-
mani, N. Rega, G.A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota,
R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H.
Nakai, M. Klene, X. Li, J.E. Knox, H.P. Hratchian, J.B. Cross, C. Adamo,
J. Jaramillo, R. Gomperts, R.E. Stratmann, O. Yazyev, A.J. Austin, R.
Cammi, C. Pomelli, J.W. Ochterski, P.Y. Ayala, K. Morokuma, G.A. Voth,
P. Salvador, J.J. Dannenberg, V.G. Zakrzewski, S. Dapprich, A.D. Daniels,
M.C. Strain, O. Farkas, D.K. Malick, A.D. Rabuck, K. Raghavachari, J.B.
Foresman, J.V. Ortiz, Q. Cui, A.G. Baboul, S. Clifford, J. Cioslowski, B.B.
Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R.L. Martin, D.J.
Fox, T. Keith, M.A. Al-Laham, C.Y. Peng, A. Nanayakkara, M. Challa-
combe, P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong, C. Gonzalez, J.A.
Pople, Gaussian 03, Revision C.02, Gaussian, Inc., Wallingford CT, 2004.
16] J.B. Foresman, in: E. Frisch (Ed.), Exploring Chemistry with Electronic
Structure Methods: A Guide to Using Gaussian, Gaussian, Pittsburg, PA,
˚
˚
˚
(
˚
˚
˚
˚
˚
6
[
1996.
[
[
17] L.J. Bellamy, The IR spectra of Complex Molecules, John Wiley and Sons,
New York, 1975.
18] A. Spire, M. Berthes, H. Kallouai, G. De Nunzio, Physics D 137 (2000)
92.
[19] J. Edler, R. Pfister, V. Pouthier, C. Falvo, P. Hamm, Phys. Rev. Lett. 93
2004) 106405.
◦
◦
◦
◦
3
◦
◦
(
[
[
[
[
20] J. Edler, P. Hamm, A.C. Scott, Phys. Rev. Lett. 88 (2002) 067403.
21] J. Edler, P. Hamm, Phys. Rev. B 69 (2004) 214301.
22] M. Barthes, G. De Nunzio, G. Ribet, Synth. Met. 76 (1996) 337.
23] N.B. Colthup, L.H. Daly, S.E. Wiberly, Introduction to Infrared and Raman
Spectroscopy, Academic Press, New York, 1975.
[24] N.P.G. Roeges, A Guide to Complete Interpretation of Infrared Spectra of
Organic Structures, Wiley, New York, 1994.
25] G. Varsanyi, Assignments for Vibrational Spectra of Seven Hundred Ben-
zene Derivatives, Wiley, New York, 1974.
26] V. Schettino, G. Sbrana, R. Righini, Chem. Phys. Lett. 13 (1972) 284.
27] G. Sbrana, V. Schettino, R. Righini, J. Chem. Phys. 59 (1973) 2441.
28] J.F. Arenas, I.T.L. Navarrete, J.C. Otero, J.I. Marcos, A. Cardenate, J. Chem.
Soc. Faraday Trans. 281 (1985) 405.
˚
˚
[
˚
˚
(
[
[
[
References
[
[
[
29] H. Ptasiewicz-Bak, J. Leciejewicz, Polish J. Chem. 71 (1997) 1350.
30] B.J. Bormans, G. de-Witr, F.C. Mijlhoff, Spectrochim. Acta 42 (1997) 121.
31] H.T. Varghese, C.Y. Panicker, D. Philip, K. Sreevalsan, V. Anithakumary,
Spectrochim. Acta 68 (2007) 817.
[
[
[
1] C.H. Endredi, F. Billes, S. Holly, J. Mol. Struct. Theochem. 633 (2003) 73.
2] F. Billes, H. Mikosch, S. Holly, J. Mol. Struct. Theochem. 423 (1998) 225.
3] A. Pawlukojc, I. Natkaniec, Z. Makrski, J. Leciejewicz, J. Mol. Struct. 516
(
2000) 7.