Crystallographic and Conformational Analyses of Zwitterionic Form of (E)-2-methoxy-6-[(2-morpholinoethylimino)methyl]phenolate

Abstract

The single crystal X-ray diffraction analysis of the title compound, C <inf>14</inf>H<inf>20</inf>N<inf>2</inf>O<inf>3</inf>, reveals that the structure is adapted to its zwitterionic form and R2<inf>2</inf> (12) centrosymmetric dimers are formed by N+-H⋯O- type ionic weak hydrogen bonds in the crystal structure. The title compound crystallizes in the triclinic space group P - 1 with a = 5.9255(13) Å, b = 9.853(3) Å, c = 12.248(3) Å, α = 101.793(19)°, β = 94.941(17)°, γ = 104.36(2)°, Z = 2, D<inf>x</inf> = 1.308 g/cm3, μ (Mo-K<inf>α</inf>) = 0.092 mm-1. The structure was solved by direct methods and refined to a final R = 0.0371 for 2183 reflections with I > 2σ (I). The crystal structure is stabilized by N+-H⋯O- type intra-molecular hydrogen bonds and N+-H⋯O- type packing interactions referred to as weak hydrogen bonds. To elucidate conformational flexibility of the title molecule, the selected torsion angle is varied from -180°to +180° in every 10° separately and then molecular energy profile is calculated and construed. In addition, charge-population analysis of the crystallographically observed structure confirms its zwitterionic form. © 2007 Springer Science+Business Media, LLC.