Furancarboxylate Coordination Polymers of Gd3+ and Eu3+: Synthesis, Structural Variations, and Biological Properties

A series of polymer complexes of Gd(III) and Eu(III) with 3-furancarboxylic (HFur) and 5-nitro-2-furancarboxylic (HNfur) acids differed in the composition and coligands presented by solvent molecules (CH 3 OH/C 2 H 5 OH/H 2 O) is synthesized: [Gd(Fur) 3 (CH 3 OH)(C 2 H 5 OH)] n ( I ), [Gd(Nfur) 3 (CH 3 OH) 2 ] n · CH 3 CN ( II ), [Eu(Fur) 3 (C 2 H 5 OH)] n ( III ), and [Eu(Nfur) 3 (H 2 O) 2 ] n ·3CH 3 CN ( IV ). According to the X-ray diffraction (XRD) data, all complexes are 1D coordination polymers in which the lanthanide cation has the coordination number 8 (LnO 8 ) to form the environment as a doubly augmented triangular prism ( I , II ) or a square antiprism ( III , IV ). The supramolecular levels of the polymers are stabilized due to intra- and intermolecular hydrogen bonds between the coordinated solvent molecules and O atoms of the chelate-bound anions of the acid and via two types of noncovalent C–H…O and N–O…π interactions that significantly contribute to an additional stabilization of the crystal packings. The biological properties of complexes I , II , and IV are studied with respect to the model nonpathogenic strain Mycolicibacterium smegmatis .