ABSTRACT
In this work, we report two exceptional framework isomers, Zn(L)(bdc)(0.5)·0.25H2O (1, HL = 1,2,4-triazol-3-amine, H2bdc = terephthalic acid) and Zn(L)(bdc)(0.5)·0.17H2O (2), where their formation is controlled by different speeds of crystallization. Further structural studies reveal that this operation of controlling the speed of crystallization may play a profound role in determining the aggregation fashions of Zn(II) ions and L(-) ligands, resulting in the various layers, viz. a 4·8(2) net vs. a 4·6·12 net. Importantly, this work also presents two previously unobserved (3,4)-connected self-penetrating matrixes.
ABSTRACT
Reported here is, for the first time, an important study of solvent effect on structural diversity in inorganic-organic mercury(II) complexes. As a result, the first supramolecular isomer in mercury(II) complexes is obtained. Importantly, a previously unobserved in situ generation of both inorganic (Cl(-)) and organic ([CH(3)-L1-CH(3)](2+)) ions was also observed.
ABSTRACT
In this work, we present the synthesis, structure, and magnetic studies of three 1D homo-spin Dy(III) compounds in detail. For 1, one crystallography-independent Dy(III) site is contained and the coordination surrounding is a distorted square-antiprism geometry. Within 2, four crystallography-independent Dy(III) sites with largely distorted square-antiprism geometry are observed. As for 3, two crystallography-independent Dy(III) sites showing bicapped triangular-prism geometry are involved. The magnetic studies suggest weak ferromagnetic interactions for 1 and weak antiferromagnetic interactions for 2 and 3. Their dynamic magnetic properties are investigated by means of alternating current (ac) susceptibility measurement, revealing their slow magnetic relaxation. Moreover, a field-dependent ac signal is observed in 1, when by applying a static dc = 1000 Oe field, strong frequency-dependent ac signals and the peak of out-of-phase (χ'') can be clearly found. Ultimately, by fitting the Arrhenius law the energy barrier and relaxation time are estimated.
ABSTRACT
Herein, we present one chiral Dy(III) compound, namely Dy(L)(3)(1, HL = 2-methylbenzoic acid), synthesized from the achiral HL ligand. Within 1, along a direction the seven-coordinated Dy(III) ion are bridged by double L carboxylate and single L oxygen to give rise to the 1D helical chain. The magnetic studies suggest small intra-chain ferromagnetic interactions. Alternating current (AC) magnetic measurements show a frequency dependence of magnetic susceptibilities in both in-phase, χ', and out-of-phase, χ''. However, no obvious peak can be found even under 1000 Oe static field, suggesting the prevalence of quantum tunnelling effect at low temperature.