Synthesis And Study On The Molecule-based Chiral Lanthanide Functional Materials With Luminescent, Ferroelectric And Magnetic Properties

Molecule-based multifunctional materials, as a novel research project in molecular materials field, have drawn considerable attention in recent years. Multifunctional materials imply that the material possess more than two physical properties, such as optical activity, ferroelectricity, magnetism, luminescence and so on. In this thesis, utilized the high luminescent efficiency and high color purity of the lanthanide ions, a series of lanthanideβ– diketone molecule-based materials with well luminescence and ferroelectricity have been designed and synthesized by the introducing of chiral organic ligands. In summary, the thesis consists of four sections as follows:1. Two pairs of enantiomers, L_2NR:(-)-4,5-pinene bipyridine (1) ; L_2NS:(+)-4,5-pinene bipyridine(2) and L_4NR:(-)-pinene pyrazine derivative (3), L_4NS:(+)-pinene pyrazine derivative (4), have been prepared and characterized by IR, GC-MS, NMR, circular dichroism (CD) spectra and X-ray single crystal diffractometer. They are mirror images in the observed CD spectra, which further confirm their enantiomers nature.2. Using theβ- diketone organic compounds 4,4,4-Trifluoro-1-(2-thienyl)-1,3- butanedione(Htta) as the first ligand and L_2NR:(-)-4,5-pinene bipyridine (1) or L_2NS:(+)-4,5-pinene bipyridine (2) as the second ligand to react with lanthanide ions, three novel pairs of enantiomers, Nd(tta)₃·L_2NR (5), Nd(tta)₃·L_2NS (6) and Yb(tta)₃·L_2NR (7), Yb(tta)₃·L_2NS (8) and Er(tta)₃·L_2NR (9) , Er(tta)₃·L_2NS (10), have been successfully synthesized. Single crystal structure analysis reveals that complexes crystallize in chiral and polar space group P21 of monoclinic system. The results of ferroelectric and photoluminescent measurement show that all of them possess well photoluminescence and ferroelectricity at room temperature.3. Using theβ- diketone organic compounds dibenzoylmethane(Hdbm) as the first ligand and L_4NR:(-)-pinene pyrazine derivative (3) or L4NS:(+)-pinene pyrazine derivativeas (4) as the second ligand to react with lanthanide ions, two novel pairs of enantiomers Sm₂(dbm)₆·L_4NR (11), Sm₂(dbm)₆·L4NS (12) and Eu₂(dbm)₆·L_4NR (13), Eu₂(dbm)₆·L4NS (14) have been successfully synthesized. Single crystal structure analysis reveals that complexes crystallize in chiral and polar space group P21 of monoclinic system. The results of ferroelectric and photoluminescent measurement show that all of them possess well photoluminescence and ferroelectricity at room temperature.4. Using the achiralβ- diketone organic molecule acetylacetone(acac) to react with the lanthanide ions vie molecular self-assembly, Two chiral tetradecanuclear hydroxo-lanthanide clusters, Ln14(μ₄-OH)₂(μ₃-OH)16(μ_-η²-acac)8(η²-acac)16?6H2O [ Ln = Tb (15), Dy (16) ], have been successfully synthesized. Single crystal structure analysis reveals that the two clusters crystallize in chiral and polar space group C₂ of monoclinic system. Photoluminescence studies reveal that 15 and 16 clusters display intense green and near white emission, respectively. Magnetic investigation shows that they are anti-ferromagnetic coupling interaction among the lanthanide ions duo to the decrease inχM^T with decreasing temperature.