Double-headed schiff bases of naphthalene-fused disalicylaldehydes: Synthesis, structural analysis and theoretical studies

The synthesis and structural features of symmetrical double-headed Schiff bases of naphthalene-fused disalicylaldehydes were discussed for the first time. Results of X-ray diffraction analysis reveal that all discussed compounds contain short intramolecular hydrogen bonds of the O[sbnd]H···N, N[sbnd]H···O, and/or C[sbnd]H···N type (the first two contacts are the key structural feature of these molecules, determining their planar structures extending over the imine linkage and leading to the formation of pseudo-six-membered rings), and molecules of studied substances are interconnected by external hydrogen bonds of the C[sbnd]H···O and/or C[sbnd]H···N type in layers or columns in the solid-state. The analysis of Hirshfeld surfaces for the obtained crystal structures shown that in all cases crystal packing dictated mainly by interatomic contacts H···H and C···H. © 2025 Elsevier B.V.