Xi- Li

Slow relaxation processes and single-ion magnetic behaviors in dysprosium-containing complexes.

A series of one-dimensional complexes [Ln(L(1))(3)(HOCH(2)CH(2)OH)](n) (L(1) = 2-furoate anion; Ln = Nd (1), Sm (2), Gd (3), Tb (4), Dy (5), Er (6)) have been synthesized. The complexes were crystallized in the monoclinic space group P2(1)/c and show a chain-like structure determined by single-crystal X-ray diffraction. Magnetic properties indicate that carboxyl group of 2-furoate mediates different magnetic couplings in light and heavy rare earth complexes, namely, antiferromagnetic interaction between light rare earth ions and ferromagnetic interaction between heavy ones. Noticeably, complex 5 displays a strong frequency dependence of alternating current (AC) magnetic properties. Further magnetic studies show a distribution of a single relaxation process in 5. While 1,10-phenanthroline and phthalate anion (L(2)) were employed, [Dy(2)(L(2))(6)(H(2)O)](n) (7) was isolated by hydrothermal reactions and characterized magnetically. Research results also show the frequency dependence of AC magnetic susceptibilities, although the phthalate anions mediate antiferromagnetic coupling between Dy(III) ions. Further magnetic investigation of a neutral mononuclear complex with the formula [Dy(TTA)(3)(L(3))] (8) (TTA = 2-thenoyltrifluoroacetonate; L(3) = 4,5-pinene bipyridine) suggests that the single-ion magnetic behavior originates the slow relaxation of Dy(III)-containing complexes.

Modulation of Homochiral DyIII Complexes: Single‐Molecule Magnets with Ferroelectric Properties

Homochiral Dy(III) complexes: by changing the ligand-to-metal ratio, enantiomeric pairs of a Dy(III) complex of different nuclearity could be obtained. The mono- and dinuclear complexes exhibit characteristics of single-molecule magnets and different slow magnetic relaxation processes. In addition, the dinuclear complexes exhibit ferroelectric behavior, thus representing the first chiral polynuclear lanthanide-based single-molecule magnets with ferroelectric properties.

A pair of mononuclear Dy(III) enantiomers showing single-ion magnetic and ferroelectric properties

Using enantiopure ligands (–)/(+)-4,5-pinene-2,2′-bipyridine (LR/LS) to react with Dy(btfa)3·2H2O, respectively, a pair of Dy(III) enantiomers with the formulae Dy(btfa)3LR (R-1) and Dy(btfa)3LS (S-1, btfa− = 3-benzoly-1,1,1-trifluoroacetonate) were obtained and structurally characterized. Each Dy(III) ion in R-1 and S-1 is octa-coordinate and adopts approximately a square-antiprismatic (SAP) geometry with D4d symmetry. Studies on the magnetic and ferroelectric properties of R-1 were carried out and the investigation results of the magnetic properties revealed that it displays a slow magnetic relaxation behavior under a zero direct-current (dc) field, confirming its single-ion magnetic (SIM) characteristic with an effective energy barrier of 95.4(1.5) K. Moreover, R-1 crystallizes in the ferroelectric point group C1, and exhibits ferroelectricity with a notable remnant polarization (Pr) value of 3.75 μC cm−2 at room temperature. All these research results also suggested that R-1 and S-1 are potential multifunctional molecule-based materials combining chiroptical activities, and ferroelectric and SIM properties within one molecule.

Towards understanding of protein adsorption behavior on plasma polymerized pyrrole film

AbstractPlasma polymerized pyrrole-like (PPpy) films exhibit good environmental stability and offer high reactivity with biomolecules. The present paper follows on from previous work on PPpy films applied as DNA immobilization/hybridization and describes the adsorption kinetics of bovine serum albumin (BSA) on PPpy films. Atom force microscopy was used to detect the surface roughness of PPpy surfaces obtained at different input powers or for different polymerization time, including the surface roughness before and after BSA adsorption. The influence of experimental conditions (i.e., the plasma input power, the polymerization time, the concentration of BSA, and the pH values of buffer solutions) on protein adsorption was investigated in situ by Surface plasmon resonance spectroscopy (SPR). SPR analysis confirmed the differently dynamic adsorption behavior of BSA on PPpy films under various experimental conditions. The adsorption constant, Ka, was deduced from Langmuir isotherm equations, which were simulated using experimental data collected by SPR and electrochemical impedance spectroscopy (EIS). Analysis of the combination data of SPR and EIS indicates that PPpy films under various conditions show completely different adsorption behaviors and could be applied as biomaterials for electrochemical protein sensing or as protein-resistant.

An intense luminescent Dy(III) single-ion magnet with the acylpyrazolonate ligand showing two slow magnetic relaxation processes

A new Dy(III) complex formulated as [Dy(pmap)3(H2O)2]·0.375CH3COOC2H5 (1) (pmap− = 1-phenyl-3-methyl-4-acetyl-5-pyrazolonate) has been synthesized and characterized. Single crystal X-ray analysis revealed that 1 crystallizes in the triclinic space group P with two crystallographically independent mononuclear molecules (denoted as Dy1 and Dy2 moieties, respectively) in its unit cell. The investigation of photophysical properties showed that 1 displays intense yellow-light emission of Dy(III) ions with a notable lifetime value of 12.75 μs. Magnetic measurement demonstrated that 1 exhibits single ion magnet (SIM) behavior with two slow magnetic relaxation processes under a 2 kOe direct-current (dc) field. Two distinct slow magnetic relaxation processes can be attributed to the presence of two Dy(III) centers with different coordination geometries (square antiprism for Dy1 and triangular dodecahedron for Dy2). Moreover, the assignment of two relaxation processes to Dy1 and Dy2, respectively, was elucidated. All these features suggest that 1 is a potential bifunctional material combining luminescent and SIM properties within one molecule. Moreover, 1 represents the first SIM with an intense luminescent property based on the acylpyrazolonate ligand.