American Journal of Physical Chemistry 2014; 3(2): 19-25 Published online May 20, 2014 (http://www.sciencepublishinggroup.com/j/ajpc) doi: 10.11648/j.ajpc.20140302.13 Theoretical and experimental investigations on molecular structure, IR, NMR spectra and HOMO-LUMO analysis of 4-methoxy-N-(3-phenylallylidene) aniline Kürşat Efil 1, 2, * , Yunus Bekdemir 2 1 Ondokuz Mayis University, Faculty of Arts and Sciences, Department of Chemistry, 55139- Samsun, Turkey 2 Canik Başarı University, Faculty of Arts and Sciences, Department of Molecular Biology and Genetics, 55080-Samsun, Turkey Email address: kursatefil@gmail.com (K. Efil), bekdemir@basari.edu.tr (Y. Bekdemir) To cite this article: Kürşat Efil, Yunus Bekdemir. Theoretical and Experimental Investigations on Molecular Structure, IR, NMR Spectra and HOMO-LUMO Analysis of 4-Methoxy-N-(3-Phenylallylidene) Aniline. American Journal of Physical Chemistry. Vol. 3, No. 2, 2014, pp. 19-25. doi: 10.11648/j.ajpc.20140302.13 Abstract: In this study, 4-Methoxy-N-(3-phenylallylidene) aniline has been synthesized and characterized by FTIR and NMR spectroscopic techniques. The optimized geometrical structure, vibrational frequencies and NMR shifts of title molecule were obtained by using ab initio HF and density functional method (B3LYP) with 6-31G* basis set. The experimental and calculated geometrical parameters were compared with each other. The calculated infrared (IR) and NMR data were compared with experimental values using HF and B3LYP/6-31G* level of theory. It was found to be a good correlation between experimental and calculated data. In addition, HOMO and LUMO analysis of title molecule were calculated using corresponding methods with 6-31G* basis set. The calculated HOMO-LUMO energies were used to calculate some properties of title molecule. Keywords: 4-Methoxy-N-(3-Phenylallylidene) Aniline, B3LYP, Hartree–Fock, IR and NMR Spectra, HOMO-LUMO 1. Introduction The compounds having the C═N group, are known as Schiff bases (also imines or azomethines), are generally synthesized by condensation of primary amines with active carbonyl compounds [1,2], The reaction is acid-catalyzed and is usually performed by refluxing the carbonyl compound and amine [3]. Schiff bases attracted much attention as they show broad spectrum of biological activities, such as antitumor [4], anticancer [5], antifungal [6], antimicrobial [7] and antiviral agents [8], furthermore they have effect as corrosion inhibitors [9,10]. We know that the quantum chemical calculations for 4-Methoxy-N-(3-phenylallylidene) aniline (MPA) have not been reported so far. In this study, optimized geometrical parameters, IR vibrational frequencies and NMR chemical shifts of MPA were computed by HF and density functional method (B3LYP) with 6-31G* basis set. The results obtained were compared with literature and our experimental ones. In addition, HOMO and LUMO analysis of title molecule were calculated using corresponding methods with 6-31G* basis set. The calculated HOMO-LUMO energies were used to calculate some properties such as ionization potential, electron affinity, electrophilicity index, chemical potential, electronegativity, chemical hardness, and softness of MPA. 2. Experimental Details 2.1. Synthesis 4-Methoxyaniline (0.123g, 1 mmol), trans- cinnamaldehyde (0.132g, 1 mmol) and two drops of -ethoxyethanol as a wetting reagent were mixed in a beaker. Then the beaker was placed in the microwave oven and was exposed to microwave irradiation (360 W). The product obtained by reaction was washed with cold ethanol. Then, it was recrystallized in ethanol. The MPA molecule was synthesized in our previous study[11]. The infrared absorption spectrum of MPA was recorded using a Bruker Vertex 80/80v spectrophotometer at room temperature. 1 H-NMR and 13 C-NMR spectra were recorded in CDCl 3 at 200 MHz in a Bruker AC spectrometer using TMS as the internal standard.