Conformational analysis and crystal structure of (E)-3-methyl-4-(p-tolyldiazenyl)phenol

Abstract

The single crystal X-ray diffraction analysis of the title compound, C14H14N2O, reveals that an interesting intermolecular or extended structure (hydrogen-bonded polymeric zigzag chains) is formed by linking its monomer units with O-H center dot center dot center dot N type intermolecular hydrogen bonds. The compound crystallizes in the monoclinic space group P2(1)/n with a 5.8151(5) angstrom, b = 18.106(1) angstrom, c = 11.515(1) angstrom and = 96.891(7)degrees. In order to understand better its structural aspects in solid state, quantum chemical (PM3) calculations were performed on a part of the extended structure of the title compound containing ten monomers. To determine in vacuo conformational flexibility of the compound, molecular energy profile of the title compound was obtained with respect to a selected torsional degree of freedom and the pedal angle varied from -180 degrees to + 180 degrees in every 10 degrees. The results from the computational study suggest that hydrogen-bonding properties in the crystal lattice is fundamental in determining the crystallographically observed conformation of the title compound.