Synthesis, spectroscopic and structural elucidation of 3-ethylamino-2-(4-nitro-benzoyl)-but-2-enoic acid phenylamide

3-Ethylamino-2-(4-nitro-benzoyl)-but-2-enoic acid phenylamide is synthesized, isolated, spectroscopical and structural characterized by means of linear-polarized IR-spectroscopy (IR-LD) of oriented solids as a colloidal suspension in nematic liquid crystal. The experimental IR-band assignment and structural information are supported by quantum chemical calculations at MP2 and B3LYP level of theory and 6-311++G** basis set. The geometry is characterized by two inramolecular hydrogen bonds of NH…OC with bond lengths of 2.589 and 3.449 Å. The NHO angles are 142.1(3)° and 125.8(4)°, respectively. A transoide configuration of amide fragments is predicted with a torsion NH-CO angle of 150.6°. Phenyl fragments are mutually perpendicular oriented closing an angle of 92.6°.