Two manganese(II) complexes constructed from 2-(3-pyridyl)-imidazo[4,5-f] 1,10-phenanthroline and organic dicarboxylates: syntheses, crystal structures, and luminescence

In this study, two new Mn(II) complexes consisting of a phenanthroline derivative and organic acid ligands, [Mn(3-PIP)(1,3-bdc)]n (1) and [Mn(3-PIP)2(1,4-bdc)]n (2) (3-PIP = 2-(3-pyridyl)-imidazo[4,5-f] 1,10-phenanthroline, 1,3-H2bdc = benzene-1,3-dicarboxylic acid, 1,4-H2bdc = benzene-1,4-dicarboxylic acid), have been synthesized via hydrothermal reaction and characterized by Fourier transform infrared (FT-IR) spectra, elemental analyses, and single-crystal X-ray diffraction. Complex 1 is a one-dimensional (1-D) twisted double chain bridged by 1,3-bdc. The 3-PIP ligands in a parallel fashion are alternately attached to both sides of the 1-D double chain. Complex 2 exhibits a 1-D zigzag chain, to which pairs of crossed 3-PIP ligands are alternately attached. The two complexes are further extended into three-dimensional (3-D) supramolecular structures by hydrogen-bonding and - stacking interactions. The N-donor ligands with an extended -system play a crucial role in formation and stabilization of the final supramolecular frameworks. Thermal properties of 1 and 2 and fluorescence of 2 are investigated in the solid state.