Syntheses, Luminescent And Magnetic Properties Of Novel Coordination Polymers

Recently, the construction of functional coordination polymers has been one ofthe research hotspots for scientists. We summarized the published works onluminescent probe, magnetism, including single-molecule magnet (SMM) andmolecular magnetic refrigeration, as well as the nanocrystallization of coordinationpolymers. From the crystal engineering, thirteen transition metal coordinationpolymers and twenty-six lanthanide coordination polymers have been synthesizeddriven by the optical and magnetic properties. Using the single crystal X-raydiffraction, elemental analysis, IR, TG, PXRD, luminescent spectra and magneticmeasurements investigated these coordination polymers. The main contributions inthis dissertation are as below:1. We designed and synthesized thirteen transition metal coordination polymersbased on the tetracarboxylic acid ligands, incliuding two1D chains (1a and3a), four2D structures (2a,2,6and8) and seven3D frameworks (1,2,3,5,7,9and10), anddiscussed the effect of synthesis conditions on the structures of the coordinationpolymers detailedly. In addition, five series of twenty-six3D lanthanide coordinationpolymers have been synthesized, of which11-13and14-21were obtained throughadjusting the solvent molecules. Coordination polymers35and36are based onoctahedral hexanuclear cluster as nodes, forming3D frameworks, and they exhibt aunique (3,12)-connected topological network, which had never been reperted.2. Five Dy-based coordination polymers (13,20,26,32and36) show slowmagnetic relaxation behavior. More interestingly, the energy barrier could be tuned byadjusting the solvent molecules, and which increased from34.49K to77.94K,improving about43.45K. Furthermore, coordination polymer35(Gd) possesses thelarge magnetic entropy change ΔSm=46.6J·kg1·K1, which was the3rdbig in thereported work at that time.3. The one Sm-(16), three Eu-(17,23and29), four Tb-(12,19,25and31) andfour Dy-coordination polymers (13,20,26and32) give the characteristic emissionsof corresponding lanthanide ions. And the fluorescence studies revel that coordinationpolymer3(Zn) can selectively sense Fe3+ion. The luminescence of coordinationpolymers17(Eu) and19(Tb) in response to organic solvents has been well studied,in which coordination polymer19can recognize the cyclohexane and nitrobenzenereversibly and sensitively. Coordination polymer19can sense the vapor of cyclohexane in30s, and only needs25min to recover to the initial value. When thenitrobenzene concentration is1ppm, the luminescence of19could become weaker,and when the nitrobenzene concentration is20%, the luminescence completelyquenched. The quenched luminescence would regenerate in about360min withoutany means.4. Adopting the solvothermal reaction without assistant methods, nano sizedparticles of coordination polymer19were prepared. Through adjusting the reactantsconcentration, different sizes of nanospheres were obtained. And the diameter ofparticles range from about70nm to1.1μm. The SEM measurement revealed that thenano-particles exhibited ball-like shape, and homogeneously dispersed. In addition, aself-made nano-film device was fabricated using the nano samples of19. And it has alot of merits, including simple preparation, low cost and convenient test operation.