Crystal structure of racemic (R/S,E)-2-(4-hydroxyphenyl)-4-(2-phenylhydrazin-1-ylidene)chromane-5,7-diol ethanol monosolvate

Abstract

The crystal structure of racemic (R/S,E)-2-(4-hydroxyphenyl)-4-(2-phenylhydrazin-1-ylidene)chromane-5,7-diol ethanol monosolvate, C21H18N2O4·C2H6O, in a centrosymmetric lattice is reported. The two racemates occupy the same position in the asymmetric unit – a disordered mixed enantiomeric structure. Hydrogen bonds of the type O—H...C(π) in addition to typical C—H...O, O—H...O and O—H...N are identified. A positional disorder is seen in the solvent molecule (ethanol) as well. The phenylhydrazone group is nearly coplanar with the chromane ring system [dihedral angle = 15.5 (1)°], while the the 4-hydroxyphenyl ring is perpendicular [dihedral angle = 87.2 (1)°] to the chromane. The pyran ring has an envelope pucker [Q = 0.363 (3) Å, θ = 57.6 (3)°; and for the enantiomer: Q = 0.364 (3) Å, θ = 127.4 (4)°].