Related Experiment Video
Updated: May 29, 2026
Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
[Synthesis, crystal structure and luminescent properties of a dysprosium coordinaation polymer based on pyridine-2,
Rui-qing Fan1, Ping Wang, Jin-yu Ren
1Department of Chemistry, Harbin Institute of Technology, Harbin, China. fanruiqing@hit.edu.cn
Abstract:
2-D layered Dy coordination polymer [Dy(PDA) (HPDA)I]n (1)(H2PDA = pyridine-2,6-dicarboxylic acid) with (4.8(2)) topological network was synthesized under hydrothermal conditions and was characterized by elemental analysis, IR spectrum, and single-crystal X-ray diffraction. X-ray diffraction analysis reveals that compound 1 is monoclinic, space group P2(1)/c. In the structure of compound 1, metal-centered Dy is connected via O atoms of H2PDA ligands to form a (4.82) topology network. The 3-D supramolecular structure of 1 is constructed through pi--pi stacking interactions between the adjacent layers. The luminescence properties of 1 were determined by UV-Vis and fluorescence spectrum in solid state at room temperature. The H2PDA and 1 exhibit the similar broad maximum absorption peak at 280 nm, which are attributed to ligand-centered pi--pi* transition. The fluorescence emission band based on ligand-center and characteristic emission of Dy3+ at the same maximum excitation wavelength of 280 nm were observed in 1. The fluorescence decay curve of complex 1 indicated that the processes of decay consists of two components, of which corresponding lifetimes tau1 = 3.61 micros and tau2 = 12.81 micros.
Related Concept Videos
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...