Three interdigitated metal–quinolone complexes from self-assembly of mixed ligands and cadmium salts

•Compound 1 is the first interdigitated metal–cfH framework assembled from 2D (6,3) nets.•Compound 2 is the first (2D → 3D) interdigitated metal–ppaH architecture.•Compound 3 defines the first example of 1D double-chain metal–levofH complex.•Compound 3 represents the first example of interdigitated metal–levofH complex.•Compounds 1–3 are three entangled metal–quinolone complexes.

Three interdigitated metal–quinolone complexes, [Cd2(cfH)2(btec)(H2O)2]·6H2O (1), [Cd2(ppaH)2(1,3-bdc)2]·4.25H2O (2) and [Cd2(LevofH)(1,3-bdc)2(H2O)2] (3) (cfH = ciprofloxacin, ppaH = pipemidic acid, LevofH = levofloxacin, btec = 1,2,4,5-benzenetetracarboxylate, 1,3-bdc = 1,3-benzenedicarboxylate) have been synthesized and characterized by elemental analyses, IR spectra, X-ray powder diffractions, TG analyses and single crystal X-ray diffraction. Compound 1 exhibits a (2D → 3D) interdigitated architecture that is first assembled from 2D wavelike (6,3) nets with side arms. Compound 2 is the first example of (2D → 3D) interdigitated metal–ppaH complex, which is constructed from sidearm-containing 2D layers of (4,4) topology. Compound 3 is built from 1D double chains with dangling levofloxacin ligands protruding from one side of the chain, and each pair of these double chains are interdigitated with each other to generate a perfect molecular zipper. By inspection of the structures of 1–3, it is believed that the short aromatic polycarboxylate ligands are important for the construction of interdigitated metal–quinolone complexes. The photoluminescent properties of compounds 1–3 have also been investigated.

Graphical abstractThree interdigitated metal–quinolone complexes, which are self-assembled from the quinolones and cadmium salts in the presence of short aromatic polycarboxylates, are reported.Figure optionsDownload full-size imageDownload as PowerPoint slide