Slow Relaxation of Magnetization in an Isostructural Series of Zinc–Lanthanide Complexes: An Integrated EPR and AC Susceptibility Study

We report the synthesis, structure, and spectroscopic and dynamic magnetic properties of a series of heterodinuclear complexes, [ZnLn(LH4 )2 ](NO3 )3 ⋅6 H2 O (Ln=Nd, Tb, Dy, Ho, Er, and Yb), with the singly deprotonated form of a new compartmentalized Schiff-base ligand, LH5 . The Ln(III) ions in these systems show a distorted square-antiprism geometry with an LnO8 coordination sphere. EPR spectroscopy and DC magnetic studies have shown that the anisotropic nature of the complexes is far more complicated than predicted on the basis of a simple electrostatic model. Among the investigated systems, only the Dy(III) derivative showed single-ion magnet behavior, in zero and an applied magnetic field, both in pure polycrystalline samples and in a series of polycrystalline samples with different degrees of dilution at the single-crystal level in the isostructural Y(III) derivative. The rich dynamics observed as functions of frequency, field, and temperature reveals that multiple relaxation mechanisms are at play, resulting in a barrier of 189 cm(-1) , which is among the highest reported for a dinuclear Zn-Dy system. Analysis of the dynamic behavior as a function of dilution degree further evidenced the persistence of non-negligible intermolecular interactions, even at the lowest concentration of 1 %

Dimers and chains of {3d-4f} single molecule magnets constructed from heterobimetallic tectons.

International audienceA tetranuclear complex and a 1-D coordination polymer with a ladder-like topology have been obtained by connecting [Ni(II)Dy(III)] nodes with dicarboxylato ligands: [Ni₂(valpn)₂Dy₂(III)(pdca)₂(NO₃)(H₂O)₆](NO₃)*4H₂O 1, and (∞)¹[Ni₂(H₂O)₂(valpn)₂Dy₂(tfa)₃]*4CH₃CN 2 (valpn²⁻ = the dianion of the Schiff base resulting from reacting o-vanillin with 1,3-propanediamine; pdca²⁻ = the dianion of 2,6-pyridinedicarboxylic acid; tfa²⁻ = the dianion of the terephthalic acid). The magnetic measurements show a ferromagnetic interaction between Ni(II) and Dy(III), and that both compounds behave like SMM with strong tunnelling. The barrier of 2 (17.4 K) is higher than that of 1 (13.6 K)

Structural characterization of 3d metal complexes containing an unconventional schiff base ligand

The design of appropriated organic ligands capable of binding metal ions provides a targeted entry to new materials with distinct structural and physicochemical properties. A representative family of such ligands includes Schiff bases. Here, we report new mono, diand polynuclear materials [Co(L)]3(ClO4)3·4H2O (1), [Zn2(L)(CH3COO)2] (2) and [Cu3(L)2(µ3 -ClO4)0.66](ClO4)1.33·1.33CHCl3 (3) containing N,N’-bis[(2- hydroxybenzilideneamino)-propyl]-piperazine (H2L) Schiff base as hexadentate ligand (Figure 1). The X-ray crystallography of the complexes reveal a retaining of the original chair piperazine conformation from the free ligand in the complex 2 and a changing into a boat conformation in the complexes 1 and 3. Moreover, in the respective complexes a different coordination number as 6 (1), 5 (2) and 4 and 5 (3) was observed upon coordination of the free ligand to Co(III), Zn(II) and Cu(II) ions. The modulatory property of H2L is reflected upon the molecular assembly and coordination mode of the isolable species

Diplomasi Indonesia terhadap Unesco dalam Meresmikan Subak sebagai Warisan Budaya Dunia

This research is about Indonesia diplomacy effort to UNESCO to inaugurate Subak in Bali as a world cultural heritage from Indonesia in 2012. Subak Bali is a cultural heritage, it is an irrigation system that regulates the division of water management based on the mindset of harmony and togetherness, it based on formal rules and religious values. Many claims by other countries that take Indonesian culture, such as batik claiming by Malaysia, its make Indonesian government ask to UNESCO to recognize Subak as Indonesian culture. Many participants help the government to get the legally, its come from local community and also the government. Subak get legally as a Indonesia heritage culture after 10 years by some process like selection, filtration and fit and proper test. This research applies realist perspective, where it focuses on state as the main actor in international politics. Indonesia wants show to the world that Indonesia also has a heritage culture. To explain this research, the author used theory of diplomacy. This research is a qualitative descriptive research. It uses the library method by taking the data from books, journals, articles, internet and other source. The author visit Department Cultural of Bali to direct research. This research applies realist perspective, where it focuses on state as the main actor in international politics. Indonesia wants show to the world that Indonesia also has a heritage culture. To explain this research, the author used theory of diplomacy. This research is a qualitative descriptive research. It uses the library method by taking the data from books, journals, articles, internet and other source. The author visit Department Cultural of Bali to direct research. The result of this research indicate that Indonesian government did multi-track diplomacy effort to get legally Subak as a world cultural heritage of Indonesia from UNESCO on 2012. The effort get a feedback from UNESCO on Mei 2012, when the Bali Heritage culture The Cultural Landscape of Bali : Subak System as a Manifestation of The Tri Hita Karana was approved to be a World Cultural heritage. It assigned in the 36th session of UNESCO in St. Petersbug, Russia on 29 June 2012. The result of this research indicate that Indonesian government did multi-track diplomacy effort to get legally Subak as a world cultural heritage of Indonesia from UNESCO on 2012. The effort get a feedback from UNESCO on Mei 2012, when the Bali Heritage culture The Cultural Landscape of Bali : Subak System as a Manifestation of The Tri Hita Karana was approved to be a World Cultural heritage. It assigned in the 36th session of UNESCO in St. Petersbug, Russia on 29 June 2012. Keywords: subak, UNESCO, cultural heritage of Bali, multy-track diplomacy Keywords: subak, UNESCO, cultural heritage of Bali, multy-track diplomac

Synthesis and structural characterization of dimeric and polymeric cooper(II) complexes with schiff base as ligand

Polynuclear coordination compounds derived from multidentate Schiff base ligands are a source of new materials with applications in catalysis [1], optoelectronic materials [2], and environmental applications [3]. In extension of our previous studies [4]on polynuclear materials, we report the crystal structures and spectroscopic properties ofdimeric and polymeric copper(II) complexeswith hexadentate Schiff base N,N’-bis[(2- hydroxybenzilideneamino)-propyl]-piperazine (H2L) as ligand. Reaction of Cu(ClO4)2 hexahydrate with H2L in the presence of triethylamine affords a polymeric structure [Cu3L2(μ3-ClO4)0.66](ClO4)1.33·1.33CHCl3(1) in which the perchlorate anion acts as a tridentate ligand in a μ3-manner binding three Cu3L2 units. When NaN3 was added to the above mentioned reaction mixturea new dimeric assembly[Cu6(C24H30N4O2)4(N3)2][ClO4]2 (2) was obtained in which two azide groups bridge two Cu3L2 unitsin an end-to-end fashion. The same dimeric structure was obtained when the polymer 1 was treated with NaN3

A missing high-spin molecule in the family of cyano-bridged heptanuclear heterometal complexes, [(LCuII)6FeIII(CN)6]3+, and its CoIII and CrIII analogues, accompanied in the crystal by a novel octameric water cluster

Three isostructural cyano-bridged heptanuclear complexes, [{CuII(saldmen)(H2O)}6{MIII(CN)6}](ClO4)3$\cdotp$8H2O (M = FeIII 2; CoIII, 3; CrIII 4), have been obtained by reacting the binuclear copper(II) complex, [Cu2(saldmen)2(mu-H2O)(H2O)2](ClO4)2$\cdotp$2H2O 1, with K3[Co(CN)6], K4[Fe(CN)6], and, respectively, K3[Cr(CN)6] (Hsaldmen is the Schiff base resulted from the condensation of salicylaldehyde with N,N-dimethylethylenediamine). A unique octameric water cluster, with bicyclo[2,2,2]octane-like structure, is sandwiched between the heptanuclear cations in 2, 3 and 4. The cryomagnetic investigations of compounds 2 and 4 reveal ferromagnetic couplings of the central FeIII or CrIII ions with the CuII ions (JCuFe = +0.87 cm-1, JCuCr = +30.4 cm-1). The intramolecular Cu-Cu exchange interaction in 3, across the diamagnetic cobalt(III) ion, is -0.3 cm-1. The solid-state1H-NMR spectra of compounds 2 and 3 have been investigated