Six hydrogen bond directed supramolecular adducts formed between racemic-bis-β-naphthol and N-containing aromatic bases

Studies concentrating on hydrogen bonding between the base of exobidentate bis(imidazole) derivatives, and 2-aminoheterocyclic compounds, and (±)-1,10-binaphthalene-2,2′-diol have led to an increased understanding of the role the aromatic N-containing compounds have in binding with (±)-1,10-binaphthalene-2,2′-diol. Here anhydrous multicomponent adducts of N-containing aromatic bases such as 1,4-bis(N-imidazolyl)butane (L1), 1,3-bis(N-benzimidazolyl)propane (L2), 1,4-bis(N-benzimidazolyl)butane (L3), 1,5-bis(N-benzimidazolyl)-3-oxapentane (L4), 2-amino-4-phenylthiazole (L5), and 2-amino-5,7-dimethyl-1,8-naphthyridine (L6) have been prepared with (±)-1,10-binaphthalene-2,2′-diol (binol). The six crystalline forms reported are cocrystals of which the crystals and complexes were characterized by X-ray diffraction analysis, IR, mp, and elemental analysis. The inter-ring angles (naphthol/naphthol) in the same binol of the six cocrystals ranged from 70.71° to 104.2° as the organic bases varied. In the six cocrystals, the binols exist either as both of the enantiomers of rac-binol or as only of its single enantiomer. All supramolecular architectures of cocrystals 1–6 are stabilized by O–H⋯N hydrogen bonds. In addition other non-conventional interactions (CH–π, CH3–π, NH–π, S–π, and π–π interactions) play an important role in the solid-state packing of co-crystallization as well. These weak interactions combined, all of the six complexes displayed 3D network structure.

► Six cocrystals have been prepared and structurally characterized. ► The noncovalent interactions between binol and aromatic bases have been ascertained. ► There all existed strong intermolecular neutral N–H···O, O–H···N hydrogen bonds. ► Aromatic interactions are also discussed in detail. ► We have shown that 3D structures can be constructed by the nonbonding interactions.