Rationally designed, polymeric, extended metal-ciprofloxacin complexes

Reactions of the antimicrobial fluoroquinolone ciprofloxacin (cfH) with metal salts in the presence of aromatic polycarboxylate ligands or under basic conditions produce fourteen new metal-cfH complexes, namely, [Ba-2(cf)(2)(1,4-bdc)(H2O)(2)](H2O)-H-. (1), [Sr-6(cf)6(1,4-bdc)(3)(H2O)(6)](.)2 H2O (2), [M-2(cfH)(2)(bptc)(H2O)(2)](.)8H(2)O (M = Mn(3) and Cd(4)), [M(cfH)(1,3-bdc)] (M = Mn(5), Co(6), and Zn(7), [Zn-2(-)(cfH)4(l,4-bdc)](1,4-bdc)-13H(2)O (8), [Ca(cfH)(2)(1,2-Hbdc)(2)](.)2H(2)O (9) and M(cf)(2)](.)2.5 H2O (M = Mn(10), Co(11), Zn(12), Cd(13), and Mg(14)) (1,4-bdc = 1,4-benzenedicarboxylate, bptc = 3,3',4,4'-benzophenonetetracarboxylate, 1,3-bdc = 1,3-benzenedicarboxylate, 1,2-bdc = 1,2-benzenedicarboxylate). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. ne structures of 1 and 2 consist of unique two-dimensional arm-shaped layers. Compounds 3 and 4 are isostructural and feature one-dimensional structures formed from the interconnection of [M-2(cfH)(2)(H2O)(2)] dimers with bptc ligands. Compounds 5-7 are isostructural and contain double-chain-like ribbons constructed from [M-2(cfH),(CO2)2] dimers and 1,3-bdc. Compound 8 consists of a pair of [Zn(CfH)(2)](2+) fragments bridged by a 1,4-bdc into a dinuclear dumbbell structure. Compound 9 is a neutral monomeric complex. To the best of our knowledge, compounds 1-9 are the first examples of metal-quinolone complexes that contain aromatic polycarboxylate ligands. Compounds 10-14 are isostruetural and exhibit interesting two-dimensional rhombic grids featuring large cavities with dimensions of 13.6 x 13.6 angstrom. Up to now, polymeric extended metal-cfH complexes have never been reported.