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Eu(III)–Sr(II)–K(I) and Tb(III)–Sr(II)–K(I) heterotrimetallic metal-organic frameworks with 2,4,6-pyridinetricarboxylic acid have been synthesized under hydrothermal conditions. The complexes are isomorphic and both in triclinic space groupP-1. The ligands bond with three metal ions with two coordination modes. One connects seven metal ions and the other connects eight metal ions. IR spectra, thermal analysis, and photoluminescent properties have been studied. The results display strong characteristic emissions of Eu(III) or Tb(III) ions with excitation of ultraviolet radiation. [ABSTRACT FROM PUBLISHER]

The reaction of the decadentate ligand tpmen (H4tpmen = N,N,N'N'-tetrakis[(6-carboxypyridin-2-yl)methyl]ethylenediamine) with MnCl2·4H2O in aqueous solution gives a homodinuclear complex [Mn2(H2O)2(tpmen)]·16H2O, which has been characterized by elemental analysis, thermal gravimetric and single-crystal X-ray diffraction analysis. The complex crystallizes in the orthorhombic system, space group Cmca, a = 28.786(5) Å, b = 11.5033(19) Å, c = 14.437(2) Å, Z = 8, R1 = 0.0432, wR2 = 0.0786. The tpmen ligand contains four picolinate groups, two of which bind each Mn(II) to form a dinuclear complex. The geometry around the Mn(II) is distorted octahedral with two nitrogen and two oxygen atoms from the picolinate groups and two oxygen atoms from coordinated water. The variable-temperature (2-300 K) magnetic susceptibilities shows an antiferromagnetic interaction between Mn(II) ions. [ABSTRACT FROM AUTHOR]