6,6′-Dihydroxy-2,2′-[(butane-1,4-diyldioxy)bis(nitrilomethylidyne)]diphenol

Abstract

The mol­ecule of the centrosymmetric title compound, C18H20N2O6, assumes an E configuration with respect to the azomethine C=N bond. The imino group is coplanar with the aromatic ring. Intra­molecular O—H⋯O and O—H⋯N bonds are found between the hydroxyl groups and adjacent O (or N) atoms. In the crystal structure, inter­molecular O—H⋯O bonds link each mol­ecule to two others, forming a layered network.

Synthesis and Crystal Structure of 3,3'-Dimethyloxy-1,1'- [butane-1,4-diyldioxybis(nitrilomethylidyne)]dibenzene

“…The molecule is disposed about a crystallographic centre of symmetry with the (-CH=N-O-(CH2)4-O-N=CH-) bridge, adopts a linear-shaped structure, in which the oxime groups and benzene rings assume anticonformation. This structure is not similar to previously reported Salen-type compounds containing four-methene bridge, which often adopt an E configuration9,10 .The two benzene rings in each molecule of the title compound are parallel and the distance between them is 0.901(3) Å. In the crystal structure, there are no intramolecular hydrogen bonds, four weak intermolecular hydrogen bonds, C10-H10B•••O2 (d(C10-H10B) = 0.96 Å, d(H10B••O2) = 2.65 Å, d(C10•••O2) = 3.461(3) Å, ∠C10-H10B•••O2 = 129º), link two other molecules into infinite zig-zag supramolecular structure(Fig.…”

Crystal structure of bis(4-hydroxybenzaldehyde) O,O'-(butane-1,4-diyl)dioxime, C18H20N2O4

“…Oximes are easily prepared from the corresponding carbonyl compounds with hydroxylamine and its analogues, and are stable to hydrolysis compared with the corresponding imines. Thus, the electrophilicity of the imino carbon of oximes is lower, and addition of nucleophiles to O-substituted oximes does not readily proceed [3].Because the oxime-type compounds are more stable to resist the metathesis of C=N bonds [4][5][6], the introduction of somefunctional groups or substitutions of someparts with appropriate ones areeffective andinevitable.…”

Crystal structure of (E)-1-(4-(((E)-3,5-dibromo-2-hydroxybenzylidene)amino)phenyl)ethan-1-one O-methyl oxime, C17H16Br2N2O2

“…Much attentions have recently been paid to the synthesis and crystal structure of oximes and their derivatives [1][2][3][4]. These compounds are an important class of organic compounds because of their applications in many elds of organic, biological, analytical chemistry [5,6] and material science [7].…”

“…The title compound was prepared by modi cation of the reported method [1][2][3][4]. To an ethanol solution (5 mL) of 4-amino acetophenone ethoxy oxime (178.0 mg, 1 mmol) was added an ethanol solution (5 mL) of 3,5-dibromosalicyladehyde (279.9 mg, 1.0 mmol).…”