Search

A photo-switchable single molecule-magnet (SMM) with two Dy ions bridged by a bis-bipyridine-dithienylethene ligand was synthesised. Isomerisation effects on the magnetic properties were investigated. Particular attention was paid to the slow relaxation of the magnetisation in order to determine precisely the role played by the ligand. Photo-isomerization of the ligand induced a geometric rearrangement of the complex and an electronic reconfiguration. The changes were studied by solid and solution state magnetic measurements. [ABSTRACT FROM AUTHOR]

Abstract: One new three-dimensional 3d–4f heterometallic coordination polymer, namely, {[EuZn2(imdc)2(C2O4)0.5(H2O)4]·2H2O} n (1) (H3imdc=imidazole-4,5-dicarboxylic acid), has been successfully synthesized by the hydrothermal reactions of Eu2O3, Zn(NO3)2·6H2O, H3imdc, H2C2O4·2H2O and H2O. Single-crystal X-ray diffraction analysis reveals that complex 1 possesses 3D heterometallic framework containing 2D layer based on L–Zn2–L (L=imdc) helical chains and L–EuZn1–L chains. Complex 1 exhibits unprecedented (3,4)-connected four-nodal topology with Schläfli symbol (6·7·8) (6·7·9) (6·72·82·10) (7·82). Moreover, the photoluminescence property of 1 was investigated in the solid-state at room temperature. [Copyright &y& Elsevier]

Abstract: Three novel lanthanide complexes, namely, [Ce(Himdc)(H2imdc)(H2O)3]·H2O (1), {[Dy(Himdc)(Ox)0.5(H2O)2]·H2O} n (2), and {[Nd(Himdc)(Ox)0.5(H2O)2]·H2O} n (3) (H3imdc=imidazole-4,5-dicarboxylic acid, Ox=oxalate), have been successfully prepared by the assembly of lanthanide ions and H3imdc ligand under different synthetic conditions. All of the complexes have been characterized by means of elemental analysis, IR, TG analysis, luminescence spectroscopy as well as single-crystal X-ray diffraction analysis. The 3D supramolecular structure of 1 is constructed from 1D zig-zag chains through the hydrogen bonding interactions. Complex 2 possesses the chair-shaped secondary building units (SBUs) with Dy6(Himdc)4(Ox)2 and meso-helical chains (P+M), resulting in a novel 2D structure based on the linkages of oxalate ligand. Complex 3 also presents 2D layer structure with uninodal 6-connected net topology, but crystallizes in the different space group and owns higher coordination number of the central metal atom than complex 2. The luminescence property of 2 is investigated in the solid state at room temperature. [Copyright &y& Elsevier]

A chiral mononuclear Dy III complex, formulated [Dy(PNO) 6 (H 2 O) 2 ]Cl 3 ( 1 ) (PNO = pyridine- N -oxide), has been prepared by using an achiral ligand through spontaneous resolution. Structure analyses show that complex 1 consists of a Dy III mononuclear unit and such units interact with each other by hydrogen bonds to form helical chains along a axis. The crystals of 1 are optically active and opposite Cotton effects can be observed in the circular dichroism (CD) spectra. Magnetic studies reveal that complex 1 exhibits field-induced single molecule magnet behavior with an energy barrier of 49 K. [ABSTRACT FROM AUTHOR]