1,1′-[m-Phenylenebis(nitrilomethanylylidene)]dinaphthalen-2-ol–1,1′-[m-phenylenebis(iminomethanylylidene)]dinaphthalen-2(1H)-one (0.58/0.42)

Abstract

In the solid state the title Schiff base, 0.58C28H20N2O2·0.42C28H20N2O2, exists both as the keto–imino and as the enol–amino tautomer, which is manifested in the disorder of the H atom in the intra­molecular hydrogen-bonded ring. The naphthalene ring systems show some distortion, which is consistent with the quinoid effect. The ratio of the enol form refined to 58 (5)%. The mol­ecule has crystallographically imposed symmetry: a twofold axis passes through the central benzene ring. Crystals are built up of layers parallel to (010). Stacking interactions between the layers involve only standard van der Waals attraction forces between apolar groups. The alignment of the aromatic rings in neighbouring layers shows a herringbone motif. A weak C—H⋯O inter­action is observed.

Crystal structure of 1,1′-{(1E,1′E)-[4,4′-(9H-fluorene-9,9-diyl)bis(4,1-phenylene)]bis(azanylylidene)bis(methanylylidene)}bis(naphthalen-2-ol) dichlorobenzene monosolvate

“…A search of the Cambridge Structural Database (CSD version 5.41, update of March, 2020; Groom et al, 2016) revealed the existence of several structurally similar bis-hydroxyimines derivatives. All of them were prepared via the condensation of the corresponding diamine and an appropriate hydroxyaldehyde (Elmali et al, 1995;Blagus & Kaitner, 2011;Popović et al, 2001;Meng et al, 2008;Wang et al, 2016;Han et al, 2015). Interestingly, although keto-enol tautamerization is a well-established phenomenon for such systems, the majority of known bis-hydroxyimines exist in enol-enol forms, except the one reported by Popović et al (2001).…”