Crystal structure, Hirshfeld surface analysis and DFT study of (5E,5'E,6Z,6'Z)-6,6'-[ethane-1,2-diyl-bis(aza-nylyl-idene)]bis-{5-[2-(4-fluoro-phen-yl)hydra-zono]-3,3-di-methyl-cyclo-hexa-none} 2.5-hydrate.

The title compound, C30H34F2N6O2·2.5H2O, was obtained by condensation of 2-[2-(4-fluoro-phen-yl)hydrazono]-5,5-di-methyl-cyclo-hexan-1,3-dione with ethyl-enedi-amine in ethanol and crystallized as a 1:2.5 hydrate in space group C2/c. The two independent mol-ecules, with approximate crystallographic C 2 symmetries, have different conformations and packing environments, are stabilized by intra-molecular N-H⋯N hydrogen bonds and linked by O-H⋯O hydrogen bonds involving the water mol-ecules. A Hirshfeld surface analysis showed that H⋯H contacts make by far the largest (48-50%) contribution to the crystal packing. From DFT calculations, the LUMO-HOMO energy gap of the mol-ecule is 0.827 eV.

Crystal structure of (E)-2,6-di-tert-butyl-4-{[2-(2,4-di-nitro-phen-yl)hydrazinylidene]meth-yl}phenol.

The essential part (including all the non-hydrogen atoms except two methyl carbons) of the mol-ecule of the title compound, C21H26N4O5, lies on a mirror plane, which bis-ects the t-butyl groups. The conformation of the C=N bond of this Schiff base compound is E, and there is an intra-molecular N-H⋯O hydrogen bond present, forming an S(6) ring motif. In the crystal, mol-ecules are linked via O-H⋯O hydrogen bonds, forming zigzag chains propagating along the a-axis direction. There are no other significant inter-molecular contacts present.