Vibrational spectroscopic studies and computational study of quinoline-2-carbaldehyde benzoyl hydrazone S.R. Sheeja a , Neema Ani Mangalam a , M.R. Prathapachandra Kurup a , Y. Sheena Mary b , K. Raju b , Hema Tresa Varghese c,1 , C. Yohannan Panicker d,1, * a Department of Applied Chemistry, Cochin University of Science and Technology, Kochi, Kerala 682 022, India b Department of Physics, University College, Trivandrum, Kerala, India c Department of Physics, Fatima Mata National College, Kollam, Kerala 691001, India d Department of Physics, TKM College of Arts and Science,Kollam, Kerala 691005, India article info Article history: Received 15 November 2009 Received in revised form 6 March 2010 Accepted 10 March 2010 Available online 16 March 2010 Keywords: FT-IR DFT Hydrazone Hyperpolarizability abstract FT-IR spectrum of quinoline-2-carbaldehyde benzoyl hydrazone (HQbH 2 O) was recorded and analyzed. The synthesis and crystal structure data are also described. The vibrational wavenumbers were examined theoretically using the Gaussian03 package of programs using HF/6-31G(d) and B3LYP/6-31G(d) levels of theory. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands obtained in infrared spectroscopy of the studied molecule. The first hyperpolarizability, infrared intensi- ties and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non-linear optics. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated values. The changes in the CAN bond lengths suggest an extended p-electron delocaliza- tion over quinoline and hydrazone moieties which is responsible for the non-linearity of the molecule. Ó 2010 Elsevier B.V. All rights reserved. 1. Introduction Hydrazides and acylhydrazones are nowadays of considerable technical and commercial importance [1]. This is connected with their wide use as drugs, photo-thermochromic compounds and precursors for organic synthesis [2–4]. In the case of acylhydra- zones the presence of the carbonyl oxygen atom promotes the for- mation of a chelate binding center [3]. Hydrazones and their metal complexes possess pronounced biological and pharmaceutical activities as antitumor [5–7], antimicrobial [8], antituberculosis [9] and antimalarial agents [10]. Hydrazones play an important role in improving the antitumor selectivity and toxicity profile of antitumor agents by forming drug carrier systems employing suit- able carrier proteins [11]. They are also employed as extracting agents in spectrophotometric determination of some ions [12– 14] and spectrophotometric determination of some species in pharmaceutical formulations [15], as well as used in catalytic pro- cesses [16,17] and waste water treatment [18]. Hydrazones, such as pyridoxal isonicotinoylhydrazone, salicyladehyde benzoylhyd- razone and 2-pyridyl carboxaldehyde-2-thiophene carboxalde- hyde hydrazone, act as orally effective drugs for the treatment of iron overload diseases or genetic diseases b-thalassemia [19,20]. Metal complexes of hydrazones have found applications in various chemical processes like non-linear optics, sensors etc. [21], and have been used in the separation and concentration of palladium and platinum in road dust [22]. Quinolines are heterocyclic com- pounds, which are worth to study for many reasons, chief among them being their prevalence among biologically active molecules [23]. Derivatives of quinoline have been widely used in the synthe- sis of antibacterial, antihypertensive and antifungal drugs [24]. These molecules possess non-centrosymmetry and hence they are widely used in the synthesis of molecules having non-linear re- sponses [24,25]. As for molecular design of new non-linear optical materials based on quinoline, the pyridine ring can be thought of as an acceptor group within the molecule, with the benzene ring as a donor. Increasing the acceptor character of the pyridine ring and/or increasing the donor character of the benzene ring would, therefore, substantially increase the non-linearity of this class of compounds [26]. Hydrazones have found wide applications in syn- thetic chemistry [27], to be used as indicators. Hydrazones are now being used extensively in detection and quantitative determina- tion of several metals, for the preparation of compounds having di- verse structures, analytical chemistry for the identification and isolation of carbonyl compounds [28]. The hydrazones have been used for different purposes such as herbicides, insecticides, 0022-2860/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.molstruc.2010.03.016 * Corresponding author. E-mail address: cyphyp@rediffmail.com (C.Y. Panicker). 1 Temporary address: Research Centre, Department of Physics, Mar Ivanios College, Trivandrum, Kerala, India. Journal of Molecular Structure 973 (2010) 36–46 Contents lists available at ScienceDirect Journal of Molecular Structure journal homepage: www.elsevier.com/locate/molstruc