2176 Research Article Received: 24 February 2009 Accepted: 26 March 2009 Published online in Wiley Interscience: 9 September 2009 (www.interscience.wiley.com) DOI 10.1002/jrs.2393 FT-IR, FT-Raman, and computational calculations of 4-chloro-2-(3-chlorophenyl carbamoyl)phenyl acetate C. Yohannan Panicker, a* Hema Tresa Varghese, b V. S. Madhavan, c Samuel Mathew, d Jarmila Vinsova, e Christian Van Alsenoy, f Y. Sheena Mary g and Y. Shyma Mary g FT-IR and FT-Raman spectra of 4-chloro-2-(3-chlorophenylcarbamoyl) phenyl acetate were studied. Vibrational wavenumbers and corresponding vibrational assignments were examined theoretically using the Gaussian03 set of quantum chemistry codes and the normal modes are assigned by potential energy distribution (PED) calculations. Simultaneous IR and Raman activation of the C O stretching mode shows the charge transfer interaction through a π -conjugated path. Optimized geometrical parameters of the title compound are in agreement with the reported values. Analysis of the phenyl ring modes shows that C–C stretching mode is equally active as strong bands in both IR and Raman, which can be interpreted as the evidence of intramolecular charge transfer via conjugated ring path and is responsible for hyperpolarizability enhancement leading to nonlinear optical activity. The red-shift of the NH-stretching wavenumber in the infrared spectrum from the computed wavenumber indicates the weakening of the NH bond resulting in proton transfer to the neighboring oxygen atom. Copyright c  2009 John Wiley & Sons, Ltd. Supporting information may be found in the online version of this article. Keywords: salicylanilide; acetate; carbamoyl; FT-IR spectra; FT-Raman spectra; DFT and PED calculations Introduction Salicylanilides (2-hydroxy-N-phenylbenzamides) have been reported as a class of compounds with a wide variety of interesting biological activities, including antimycobacterial and antifungal effects. [1–8] They act as inhibitors of the two-component regulatory system (TCS) in bacteria. [9,10] The importance of electron-attracting substituents in the salicyloyl ring and hydrophobic groups in the anilide moiety for optimal activity has been noted and the removal of the 2-OH group resulted in the loss of activity. [9] Anion triggered substituent dependent conformational switching of salicylanilides was reported by Guo et al. [11] Imramovsky et al. [12] reported the synthesis and characterization of a series of novel, highly an- timicrobial salicylanilide esters of N-protected amino acids. The synthesis and antimicrobial evaluation of a series of variously ring- substituted salicylanilide acetates are reported by Vinsova et al. [3] Salicylanilides have been the subject of intensive interest in medici- nal chemistry, due to their ability to serve as inhibitors of the protein tyrosine kinase epidermal growth factor receptor relating to can- cer, psoriasis, and restenosis. [8,13] Dahlgren et al. [4] reported the design, synthesis, and multivariate quantitative structure-activity relationship of salicylanilides and Singh et al. [14] reported the synthesis of 5-chloro-3 ′ -nitro-4 ′ substituted salicylanilides. Boyce et al. [15] described the structure – activity relationship guided con- version of bioactive salicylanilides into a comparably bioactive derivative which was utilized as a tool for protein identifica- tion. Arslan et al. [16] reported the molecular structure and vibra- tional spectra of 2-chloro-N-(diethylcarbamothioyl) benzamide by Hartree-Fock (HF) and density functional methods. Kinetics and mechanism for the reactions of N-methyl-N-phenylcarbamoyl chlorides with benzylamines in acetonitrile were reported by Koh et al. [17] The spin trapping behavior of carbomyl substituted derivatives, toward different oxygen- and carbon-centred radicals is reported. [18] Biagi et al. [19] reported the synthesis and biological activity of novel substituted benzanilides as potassium channel activators. Matyk et al. [20] reported the synthesis of a series of 64 derivatives of substituted heterocyclic analogues of salicylanilides and the compounds were evaluated for in vitro antimycobacte- ∗ Correspondence to: C. Yohannan Panicker, Department of Physics, TKM College of Arts and Science, Kollam 691005, Kerala, India. E-mail: cyphyp@rediffmail.com a Department of Physics, TKM College of Arts and Science, Kollam 691005, Kerala, India b Department of Physics, Fatima Mata National College, Kollam 691001, Kerala, India c Department of Physics, MES Ponnani College, Ponnani South, Malappuram, Kerala, India d Department of Physics, Mar Thoma College, Thiruvalla 689 103, Kerala, India e Department of Inorganic and Organic Chemistry, Faculty of Pharmacy, Charles University, 500 05 Hradec Kralove, Czech Republic f University of Antwerp, Chemistry Department, Universiteitsplein 1, B2610 Antwerp, Belgium g Thushara, Neethinagar-64, Pattathanam, Kollam, 691021, Kerala, India J. Raman Spectrosc. 2009, 40, 2176–2186 Copyright c  2009 John Wiley & Sons, Ltd.