CRYSTAL STRUCTURE AND DFT STUDIES OF 4-(1-BENZYL-5-METHYL-1H-1,2,3-TRIAZOL-4-YL)-6-(3- METHOXYPHENYL)PYRIMIDIN-2-AMINE

Abstract

The title compound 1, 4-(1-benzyl-5-methyl-1H-1,2,3-triazol-4-yl)-6-(3-methoxyphenyl)pyrimidin-2-amine (C 21 H 20 N 6 O), was synthesized and structurally characterized by elemental analysis, 1H NMR, 13C NMR and single crystal X-ray diffraction. The molecular conformation is stabilized by an intramolecular C–H…N hydrogen bond, which generates an S(6) ring motif. In the crystal, molecules are linked by two pairs of inversion-related amine N-H N and C-H N hydrogen bonds, each generating alternate R 2 2(8) ring motifs in a zigzag supramolecular chain that runs along c-axis. These chains stack along a-axis via amine N-H…O hydrogen bonds forming a two-dimensional supramolecular network. Density functional theory calculations of the structure, Mulliken population analyses on atomic charges and thermodynamic functions of the title compound were performed by using (DFT/B3LYP) method with the 6-311G(d,p) basis set level. The charge energy distribution and site of chemical reactivity of molecules were obtained by mapping electron density isosurface with electrostatic potential surfaces. The thermo dynamical properties of the title compound at different temperature have been calculated and corresponding relations between the properties and temperature have also been obtained. 1,2,3-triazoles found to have wide range of important applications in the pharmaceutical, polymer, and material fields 1. In addition, they have shown a broad spectrum of biological properties such as anti-bacterial2 anti-allergic3, anti-HIV activity4 and also serve as potential chemotherapeutic agents for various diseases5. On the other hand, substituted pyrimidine nuclei are found antiviral6, anti-tubercular, antineoplastic, anti-inflammatory, diuretic, antimalarial and cardiovascular7. In view of these bioactivities of the individual heterocycles, it was envisaged that the synthesis of novel hybrid molecules containing two of the above said moieties in a single frame is worth to attempt. Literature survey reveals that so for there is no experimental and theoretical study for the title compound. In recent years, density functional theory (DFT) has become an increasingly useful tool for theoretical studies. The success of DFT is mainly due to the fact that it describes small molecules more reliably than Hartree-Fock theory. It is also computationally less demanding than wave function based methods with inclusion of electron correlation8-9. Thus, in order to characterize the correlation between molecular structure and macroscopic properties in the studied compound, it seems to be essential to undertake a detailed comparative study of the isolated molecule and the solid state unit. In this paper, a concerted approach by X-ray crystallography and DFT calculation was used, which takes advantage of both the high interpretative power of the theoretical studies and the precision and reliability of the experimental method. The title compound has been synthesized and antibacterial activities are reported by our co-authors10. In this paper, we report the synthesis, crystal structure of 4-(1-benzyl-5-methyl-1H-1,2,3-triazol-4-yl)-6-(3-methoxyphenyl) pyrimidin-2-amine (C 21 H 20 N 6 O), as well as theoretical studies using the DFT(B3LYP) method and 6-311G(d,p) basis set. The aim of the present work was to describe and characterize the molecular structure and some electronic structure properties of the title compound, both experimentally and theoretically. Also, chemical reactivity values such as chemical hardness, chemical potential electronegativity and electrophilicity index and HomoLumo energy gap obtained theoretically can be used to understand the biological activity of the title compound.