Structures And Properties Of Lanthanide Complexes Constructed From N/O-containing Ligands

In this paper, we selected the rigid carboxylate and nitrogen-bearing heterocyclic ligands with lanthanide metals to construct novel coordination complexes, and fifty-two new complexes have been successfully synthesized and characterized by single-crystal X-ray diffraction (XRD), infrared spectroscopy (IR), elemental analysis (EA) and powder X-ray diffraction (PXRD). Their structures have been analysized by topological approach. The thermogravimetric, magnetic, and photoluminescent properties have also been studied. Main results for the paper are as follows:1. Complexes1-13were constructed from3,5-dichlorobenzoic acid and pyridyl ligands (Chapter2). Complex1affords ID chains with hexanuclear La6units. Complex2gives1D Dy chains, which are in turn bridged by double and quadruple carboxylate. In complex3Cd2Mn trinuclear units connect into2D supramolecular layers by hydrogen bonds and π-π packing interactions. Complexes4and5are isomers formed under different pH values, whereas belong to different space groups, and formed different supramolecular structures. Complexes6-10are tetranuclear units of Cu(II) and Ln(III) ions. Complexes11-13are ZnLn dinuclear units which spread into2D supramolecular sheets. And the thermogravimetric, PXRD properties of1and2, magnetic property of2,3,5,6,9,11-13have been investigated. Dynamic magnetic susceptibility studies reveal slow magnetic relaxation processes for11-13, suggesting single molecule magnetic (SMM) type behavior. The influence of the reaction pH and lanthanide contraction on different structures has been discussed.2. Complexes14-20were constructed from3,5-dinitrobenzoic acid and pyridyl ligands (Chapter3). Complexes14and15are one-dimensional Ln chains and Fe(II) ions scatter among1D Ln chains. Complex16is composed of tetranuclear units Cu2Y2, in which coordination environments of Cul and Cu2, Yl and Y2are different. Complexes17-20are Cu2Ln2tetranuclear units which extended into3D supramolecular framework. The magnetic properties of15,17and20have been studied in detail. The influence of the main ligand, structure-directing reagent and lanthanide contraction on different structures has been discussed. 3. Complexes21-38were constructed from4-(trifluoromethyl)benzoic acid,3,5-bis(trifluoromethyl)benzoic acid and pyridyl ligands (Chapter4). Complexes21-24are tetranuclear units which extended into different supramolecular structures. Complexes25and26are isostructural, and they consist of linear tetrameric Ln4units which are connected through carboxylate into a one-dimensional zigzag chain and spread into2D supramolecular (4,4) sql net. Complexes27and28are isostructural and the dinuclear units are extended into1D supramolecular chains. Complexes29-34are tetranuclear units which extended into different supramolecular structures. Complexes35-38are trinuclear units which extended into supramolecular structures. The magnetic, fluorescent, thermogravimetric and PXRD properties have been investigated. Dynamic magnetic susceptibility studies reveal slow magnetic relaxation processes for21,23and31, suggesting SMM type behavior. Complexes26and27show the characteristic fluorescent bands for the Sm(III) and Tb(III) ions, respectively.4. Complexes39-49were constructed from D(+)-camphoric acid (D-H2Cam) and pyridyl ligands (Chapter5). Complexes39-49are isostructural, crystallizing in the orthorhombic space group P212121and they exhibit unique3D chiral6-connected frameworks involving1D zigzag chains aligned parallel to the a axis and the2D wave-like lanthanide layers. Magnetic studies reveal that ferromagnetic interactions between Co(II) and some Ln(III) ions are presented for the first time as3d-4f MOFs of D-H2Cam with ferromagnetic behaviors and may be significant to construct molecular magnets or magnetic coolers.2.5. Complexes50-52were constructed from5-amino-tetrazolate (Chapter6). Complex50forms a bilayer honeycomb feature, in which water molecules filled. Complex51is2D layer structure which is build by Zn2units in be plane. Complex52is one dimensional helix chain in b axis. The photoluminescence properties show that the three complexes have good fluorescence properties. The influence of metal ions on different structures has been discussed.