Two three-dimensional silver(I) coordination architectures with pyridine-3,5-dicarboxylate: Luminescence and structural dependence on preparing conditions

The hydrothermal reactions of pyridine-3,5-dicarboxylic acid (H2pydc) with AgNO3 in the mixed solvent of acetonitrile and water with different ratios lead to the formation of two three-dimensional network complexes, [Ag5(pydc)2(CN)]n (1) and {[Ag4(pydc)2]CH3CN}n (2), which have been characterized by IR, single-crystal X-ray diffraction and thermogravimetric analyses. It has been demonstrated that the ratio of acetonitrile and water have great effect on the structures of products. The high ratio of acetonitrile and water is favorable for the formation of complex 1, while the low volume ratio is propitious to complex 2. The luminescent properties of complex 1 and 2 have been further investigated, and show that the luminescence intensity of 2 is much stronger than that of 1 probably due to the direct metal–metal interactions and a larger HOMO–LUMO gap in complex 2.