Synthesis, structure and fluorescence of two novel manganese(II) and zinc(II)-1,3,5-benzene tricarboxylate coordination polymers: Extended 3D supramolecular architectures stabilised by hydrogen bonding

Two new coordination polymers {[Mn(H2btc)(phen)(H2O)2]H2btc · H2O}n (1) [H3btc = 1,3,5-benzene tricarboxylic acid, phen = phenanthroline] and {[Zn3(btc)2(H2O)8](H2O)4}n (2) have been synthesised and structurally characterised. Both the complexes crystallise as 1D chain, which further propagates through ligand-based hydrogen bonding interactions into a 3D supramolecular architecture. Supramolecular framework of 1 is constructed by [Mn(H2btc)(phen)(H2O)2]+ as well as the constituent materials–uncoordinated H2btc− and water molecules. Complex 2 exists as a corrugated chain with both the bridging and terminal Zn2+ ions and each zinc centre is coordinated to four water molecules. Both 1 and 2 are stacked by mutual π-stacking of the ligands and exhibit strong fluorescence emission band at 414 and 400 nm, respectively.