Source:http://linkedlifedata.com/resource/pubmed/id/17845030
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| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
21
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| pubmed:dateCreated |
2007-10-8
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| pubmed:abstractText |
The self-assembly reaction between trivalent lanthanide ions, 2,2':6',2' '-terpyridine (terpy) ligand, and octacyanotungstate(V) leads to the formation of two series of isomorphous cyano-bridged compounds: (i) one-dimensional (1-D) chains [Ln(terpy)(DMF)(4)][W(CN)(8)].6H(2)O.C(2)H(5)OH (Ln = Ce-Dy) and (ii) dinuclear molecules [Ln(terpy)(DMF)(2)(H(2)O)(2)][W(CN)(8)].3H(2)O (Ln = Ho, Er, Yb) and the ionic [Tm(III)(terpy)(DMF)(2)(H(2)O)(3)][WV(CN)(8)].4H(2)O.DMF (DMF = N,N-dimethylformamide) system. The crystal structures of 1-D chains consist of alternating {[W(CN)(8)]} and {[Ln(terpy)]} building blocks. The neighboring chains are weakly linked through the pi-pi stacking interactions of the aromatic rings, leading to two-dimensional supramolecular layers. The dinuclear species are weakly linked through the hydrogen bonds between H2O molecules and terminal cyano ligands resulting in a columnlike arrangement of dimers. Taking into account the ligand-field splitting and the exchange interaction, we have estimated the magnetic couplings between the Ln(III) and WV centers in a series of polycrystalline 1-D chains and in dimeric systems. The corresponding exchange constants have been shown to change the sign along the series of chains. The coupling is antiferromagnetic for 1 (J = -0.24 cm(-1)) and 2 (J = -0.07 cm(-1)), whereas 3 (J = +0.47 cm(-1)), 7 (J = +0.28 cm(-1)), and 8 (J = +0.23 cm(-1)) have ferromagnetic character. In the case of dimeric systems, the coupling constants seem to be independent of the lanthanide center. The splitting structures of the ground-state multiplets of the Ln(III) centers have been shown to explain the temperature dependences of the magnetic susceptibilities.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:status |
PubMed-not-MEDLINE
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| pubmed:month |
Oct
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| pubmed:issn |
0020-1669
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:day |
15
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| pubmed:volume |
46
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
8924-38
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| pubmed:year |
2007
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| pubmed:articleTitle |
Tuning of magnetic properties of polynuclear lanthanide(III)-octacyanotungstate(V) systems: determination of ligand-field parameters and exchange interaction.
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| pubmed:affiliation |
Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland.
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| pubmed:publicationType |
Journal Article
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