Crystal Structure and Vibrational Spectra of 3-Chloro-4-Phenyl-6-(Morpholine-4-yl)-Pyridazine by Hartree-Fock and Density Functional Methods

Abstract

The title compound, 3-chloro-4-phenyl-6-(morpholine-4-yl)-pyridazine (I), was prepared and characterized using elemental analysis and FT-IR and ¹H NMR spectroscopy studies. The crystal and molecular structure of the title compound was determined from single-crystal X-ray diffraction data. It crystallizes in the orthorhombic space group P2₁2₁2₁, Z = 8 with a = 7.5743 (3) Å, b = 14.8922 (8) Å, c = 23.3472 (9) Å, V = 2633.5 (2) ų, and D_x = 1.391 Mg/m³. The title compound, C₁₄H₁₄ClN₃O, crystallizes with two independent molecules A and B in the asymmetric unit, wherein the morpholine ring adopts a distorted chair conformation. The 1,6-dihydropyridazine ring creates dihedral angles of 47.0(3)° (in molecule A) and 47.9(2)° (in molecule B) with the phenyl ring, respectively. The crystal studied was an inversion twin with a 0.56(12):0.44(12) domain ratio. The molecular structure, vibrational frequencies, and intensities of the title compound were calculated using Hartree-Fock and density functional theory methods (BLYP, B3LYP, B3PW91, and mPW1PW91) using the 6-31G(d,p) basis set. The calculated geometric parameters were compared to the corresponding single crystal X-ray structure of the title compound. Comparison of the theoretical and experimental geometries of the title compound show that the X-ray parameters are in good agreement with the optimized molecular structure of the title compound. In addition, the harmonic vibrations computed for this compound using the B3LYP/6-31G(d,p) method are in good agreement with the observed vibrational spectral data. Theoretical vibrational spectra of the title compound were interpreted using PEDs and the VEDA 4 program. The superior performance of these investigated methods was calculated using the PAVF 1.0 program.

Keywords:

• Ab initio calculations
• alkanoic acids
• B3LYP
• DFT
• infrared spectrum
• non-steroidal anti-inflammatory drugs
• vibrational frequencies