Synthesis and characterization of di-, tri- and tetranuclear carboxylate complexes containing both lanthanide(III) and zinc(II) ions

摘要

Treatment of Lri(NO3)3.6l-t20, Zn(NO3)2.6H2O and carboxylic acids with quinoline in stoichiometric molar ratios in ethanol produces four structural types of carboxylate-bridged lanthanide(l11)-zinc(II) complexes [C9H7N-H][LnZn(O2CC2- HS)3(C9H7N)(N°3)3fH2O (Ln = Er lor Y 2), [DyZn2(O2CCMe3)6(C9H7N)2(NO3)] (3), [DyZn2(~-O2CC2HS)s(O2CC2Hs)- (C9H7N)2(NO3)(H2O)] (4) and [Gd2Zn2(O2CC2Hs)8(C9H7N)2(N°3)2(H2O)2] (5), all of which have been characterized by single-crystal X-ray diffraction. Complexes 1 and 2 are isostructural and comprise quinolinium cations, triply propionate-bridged dimeric LnZn anions and lattice water molecules. In 3 the central Dy ion and two terminal Zn ions are bridged by two sets of three equivalent bismonodentate pivalate ligands to form a symmetrical trinuclear DyZn2 structure. While the Dy ion in 4 is connected to one Zn ion via three bismonodentate propionate ligands and connected to another Zn via only two bismonodentate propionate ligands generating a novel unsymmetrical trinuclear DyZn2 structure. Complex 5 consists of two triply propionate- bridged dinuclear [GdZn(O2CC2Hs)3(C9H7N)(NO3)(H2O)] subunits, being linked together by two tridentate propionate groups via two Gd ions. The magnetic properties 6f complex 5 containing a pair of Gd3 + ions bridged by two carboxylate groups have been investigated, A quantitative analysis of the magnetic data shows the interaction is of antiferromagnetic type with a J constant of -0.042 cm~(-1).