Two novel entangled metal-quinolone complexes with self-threading and polythreaded characters

Reactions of quinolones with metal salts in the presence of aromatic polycarboxylate ligands under hydrothermal conditions yield two novel entangled metal-quinolone complexes, namely [Cd-2(sar-aH) (2)(bpdc)(2)]center dot 4.5H(2)O (1) and [Mn(sara)(2)]center dot 2.5H(2)O (2), (saraH = sarafloxacin, bpdc = 4,4'-biphenyldicarboxylate). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, X-ray powder diffraction, and TG analyses. Compound 1 is an uncommon 2D self-threading network, which represents the first entangled network constructed from mixed sarafloxacin and dicarboxylate ligands. Compound 2 exhibits a novel (2D -> 3D) polythreaded architecture that is constructed from 2D 4(4)-sql nets with side arms, which represents the first example of polythreaded metal-sarafloxacin complex. A comparison of the structures of 1 and 2 shows that the pH plays a crucial role in tuning the structures of the metal-quinolone complexes. Furthermore, the luminescent properties of compound 1 are discussed. (C) 2012 Elsevier B.V. All rights reserved.