Syntheses, crystal structures, and luminescence of two main-group metal complexes based on 3,4-pyrazoledicarboxylic acid

摘要

Two new metal complexes, [Pb(H_2pdc)_2(H_2O)] ? 2H_2O (1) and [Sr_2(H_2pdc)_4(H_2O)_8] ? 2H_2O (2) (H_3pdc = 3,4-pyrazoledicarboxylic acid), have been synthesized and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. In 1, the geometry of Pb(II) is hemidirected and the 6s~2 lone electron pair on Pb(II) is stereochemically active, resulting in the formation of a secondary Pb ? ? ? O bond. The weak Pb ? ? ? O interactions, π-π stacking, and hydrogen-bonding interactions construct 1 into a 3-D framework with 1-D channels. Complex 2 is a dinuclear structure, which is further assembled to a 3-D supramolecular network through intermolecular hydrogen bonds and π-π stacking. Three coordination modes of 3,4-pyrazoledicarboxylic acid were observed. The thermal and photoluminescent properties of 1 and 2 in the solid state have also been investigated.