The FT-Raman and FT-IR spectra for 1-bromo-2-chlorobenzene (1B2CB) have been recorded in the region 4000–100？cm？1 and compared with the harmonic vibrational frequencies calculated using HF/DFT (B3LYP) method by employing 6-31+G (d, p) and 6-311++G (d, p) basis set with appropriate scale factors. IR intensities and Raman activities are also calculated by HF and DFT (B3LYP) methods. Optimized geometries of the molecule have been interpreted and compared with the reported experimental values of some substituted benzene. The experimental geometrical parameters show satisfactory agreement with the theoretical prediction from HF and DFT. The scaled vibrational frequencies at B3LYP/6-311++G (d, p) seem to coincide with the experimentally observed values with acceptable deviations. The theoretical spectrograms (IR and Raman) have been constructed and compared with the experimental FT-IR and FT-Raman spectra. Some of the vibrational frequencies of the benzene are affected upon profusely with the halogen substitutions in comparison to benzene, and these differences are interpreted. 1. Introduction Aromatic compounds such as benzene derivative compounds are commonly used for chronic inflammation treatment products in pharmaceutical products. Benzene is frequently used as an industrial solvent, especially for degreasing metal. Chlorobenzene is an important industrial solvent and a widely used intermediate in production of commodities such as herbicides, dyestuffs, and rubber [1]. The major use of Chlorobenzene is as an intermediate in the production of commodities such as herbicides, dyestuffs, and rubber. Chlorobenzene is also used as a high-boiling solvent in many industrial applications as well as in the laboratory. Bromobenzene can be used to prepare the corresponding Grignard reagent, phenyl magnesium bromide [2]. The combined Chlorobromobenzene is also used for the manufacture of some biological and industrial solvents. In recent years, chlorobromobenzene has been the frequent subject of experimental and theoretical work because of its significance in industry and environment. Literature survey reveals that to the best of our knowledge no ab initio HF/DFT with 6-31+G (d, p) and 6-311++G (d, p) basis sets calculations of 1-Br-2-CB have been reported so far. It is, therefore thought worthwhile to make a comprehensive vibrational analysis using both experimentally observed IR and Raman wavenumbers and theoretically calculated vibrational spectra. In this study, molecular geometry, optimized parameters, and vibrational frequencies are computed and the performance
References
[1]
C. Long, Q. Li, Y. Li, Y. Liu, A. Li, and Q. Zhang, “Adsorption characteristics of benzene-chlorobenzene vapor on hypercrosslinked polystyrene adsorbent and a pilot-scale application study,” Chemical Engineering Journal, vol. 160, no. 2, pp. 723–728, 2010.
[2]
M. Rossberg, et al., “Chlorinated hydrocarbons,” in Ullmann's Industrial Chemistry, Wiley-VCH, Weinheim, Germany, 2006.
[3]
A. D. Becke, “Density-functional exchange-energy approximation with correct asymptotic behavior,” Physical Review A, vol. 38, no. 6, pp. 3098–3100, 1988.
[4]
C. Lee, W. Yang, and R. G. Parr, “Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density,” Physical Review B, vol. 37, no. 2, pp. 785–789, 1988.
[5]
A. D. Becke, “Density-functional thermochemistry. III. The role of exact exchange,” The Journal of Chemical Physics, vol. 98, no. 7, pp. 5648–5652, 1993.
[6]
Z. Zhou, D. Du, Y. Xing, and S. U. M. Khan, “Calculation of the energy of activation in the electron transfer reaction not involving the bond rupture the electrode,” Journal of Molecular Structure: THEOCHEM, vol. 505, pp. 247–255, 2000.
[7]
Y. Carissan and W. Klopper, “Hydrogen abstraction from biphenyl, acenaphthylene, naphthalene and phenanthrene by atomic hydrogen and methyl radical: DFT and G3(MP2)-RAD data,” Journal of Molecular Structure: THEOCHEM, vol. 940, no. 1–3, pp. 115–118, 2010.
[8]
M. H. Jamróz and J. Cz. Dobrowolski, “Potential energy distribution (PED) analysis of DFT calculated IR spectra of the most stable Li, Na, and Cu(I) diformate molecules,” Journal of Molecular Structure, vol. 565-566, pp. 475–480, 2001.
[9]
D. C. Young, Computational Chemistry: A Practical Guide for Applying Techniques to Real world Problems, John Wiley & Sons, New York, NY, USA, 2001.
[10]
M. Sekerci, Y. Atalay, F. Yakuphanoglu, D. Avci, and A. Ba？o？lu, “A theoretical study on 1-(thiophen-2-yl-methyl)-2-(thiophen-2-yl)-1H-benzimidazole,” Spectrochimica Acta Part A, vol. 67, no. 2, pp. 503–508, 2007.
[11]
A. P. Scott and L. Radom, “Harmonic vibrational frequencies: An evaluation of Hartree-Fock, M？ller-Plesset, quadratic configuration interaction, density functional theory, and semiempirical scale factors,” Journal of Physical Chemistry, vol. 100, no. 41, pp. 16502–16513, 1996.
[12]
“Gaussian 03 program,” Gaussian Inc., Wallingford, Conn, USA, 2000.
[13]
M. J. Frisch, A. B. Nielsen, and A. J. Holder, Gauss View Users Manual, Gaussian, Pittsburgh, Pa, USA, 2000.
[14]
H. M？llendal, S. Gundersen, M. A. Tafipolsky, and H. Vidar Volden, “The molecular structure of benzene derivatives, part 2: 4-chloro-benzaldehyde by joint analysis of gas electron diffraction, microwave spectroscopy and ab initio molecular orbital calculations,” Journal of Molecular Structure, vol. 444, no. 1–3, pp. 47–56, 1998.
[15]
S. Samdal, T. G. Strand, M. A. Tafipolsky, L. V. Vilkov, M. V. Popik, and H. V. Volden, “The molecular structure of benzene derivatives part 1.4-fluorobenzaldehyde by joint analysis of gas electron diffraction, microwave spectroscopy and ab initio molecular orbital calculations,” Journal of Molecular Structure, vol. 435, no. 1, pp. 89–99, 1997.
[16]
A. K. Hermetet, L. J. Ackerman, K. K. Eilts et al., “Structural, spectral and thermal studies of N-2-(4,6-lutidyl)- -chlorophenylthioureas,” Journal of Molecular Structure, vol. 605, no. 2-3, pp. 241–247, 2002.
[17]
S. Ramalingam, S. Periandy, M. Govindarajan, and S. Mohan, “FTIR and FTRaman spectra, assignments, ab initio HF and DFT analysis of 4-nitrotoluene,” Spectrochimica Acta Part A, vol. 75, no. 4, pp. 1308–1314, 2010.
[18]
S. Ramalingam, S. Periandy, B. Narayanan, and S. Mohan, “FTIR and FTRaman spectroscopic investigation of 2-bromo-4-methylaniline using ab initio HF and DFT calculations,” Spectrochimica Acta Part A, vol. 76, no. 1, pp. 84–92, 2010.
[19]
L. J. Bellamy, The Infrared Spectra of Complex Molecules, Chapman and Hall, London, UK, 1975.
[20]
G. Socrates, Infrared and Raman Characteristics Group Frequencies, Wiley, New York, NY, USA, 3rd edition, 2001.
[21]
N. Sundaraganesan, H. Saleem, S. Mohan, M. Ramalingam, and V. Sethuraman, “FTIR, FT-Raman spectra and ab initio DFT vibrational analysis of 2-bromo-4-methyl-phenylamine,” Spectrochimica Acta Part A, vol. 62, no. 1–3, pp. 740–751, 2005.
[22]
V. Krishnakumar and R. John Xavier, “Normal coordinate analysis of 2-mercapto and 4,6-dihydroxy -2-mercapto pyrimidines,” Indian Journal of Pure and Applied Physics, vol. 41, no. 8, pp. 597–601, 2003.
[23]
V. Krishnakumar and N. Prabavathi, “Simulation of IR and Raman spectral based on scaled DFT force fields: a case study of 2-amino 4-hydroxy 6-trifluoromethylpyrimidine, with emphasis on band assignment,” Spectrochimica Acta Part A, vol. 71, no. 2, pp. 449–457, 2008.
[24]
A. Altun, K. G？lcük, and M. Kumru, “Structure and vibrational spectra of p-methylaniline: Hartree-Fock, MP2 and density functional theory studies,” Journal of Molecular Structure: THEOCHEM, vol. 637, pp. 155–169, 2003.
[25]
S. J. Singh and S. M. Pandey, Indian Journal of Pure and Applied Physics, vol. 12, pp. 300–304, 1974.
[26]
Y. X. Sun, Q. L. Hao, Z. X. Yu, W. J. Jiang, L. D. Lu, and X. Wang, “Experimental and theoretical studies on vibrational spectra of 4-(2-furanylmethyleneamino)antipyrine, 4-benzylideneaminoantipyrine and 4-cinnamilideneaminoantipyrine,” Spectrochimica Acta Part A, vol. 73, no. 5, pp. 892–901, 2009.
[27]
N. Sundaraganesan, B. D. Joshua, and T. Radjakoumar, “Molecular structure and vibrational spectra of 2-chlorobenzoic acid by density functional theory and ab-initio Hartree-Fock calculations,” Indian Journal of Pure and Applied Physics, vol. 47, no. 4, pp. 248–258, 2009.
[28]
D. N. Sathyanarayana, Vibrational Spectroscopy Theory and Application, New Age International, New Delhi, India, 2004.
[29]
V. R. Dani, Organic Spectroscopy, Tata-MacGraw Hill Publishing, New Delhi, India, 1995.
[30]
J. Mohan, Organic Spectroscopy—Principle and Applications, Narosa Publishing House, New Delhi, India, 2nd edition, 2005.
[31]
P. S. Kalsi, Spectroscopy of Organic Compounds, Wiley Eastern, New Delhi, India, 1993.
[32]
A. R. Prabakaran and S. Mohan, Indian Journal of Physics, vol. 63B, pp. 468–473, 1989.
[33]
N. S. Chiu, J. D. Ewbank, M. Askari, and L. Sch？fer, “Molecular orbital constrained gas electron diffraction studies. Part I. Internal rotation in 3-chlorobenzaldehyde,” Journal of Molecular Structure, vol. 54, pp. 185–195, 1979.
[34]
E. F. Mooney, “The infra-red spectra of chloro- and bromobenzene derivatives-II. Nitrobenzenes,” Spectrochimica Acta, vol. 20, no. 6, pp. 1021–1032, 1964.
[35]
C. S. Hiremath and T. Sundius, “Vibrational spectra, ab initio/DFT electronic structure calculations, and normal coordinate analysis of 2-bromo-5-fluorobenzaldehyde,” Spectrochimica Acta Part A, vol. 74, no. 5, pp. 1260–1267, 2009.
[36]
L. J. Bellamy, The Infrared Spectra of Complex Molecules, Chapman & Hall, London, UK, 1975.
[37]
G. Varsanyi, Assignments for Vibrational Spectra of 700 Benzene Derivatives, vol. 1, Hilger, London, UK, 1974.
