Journal Article

PreJuSER-22478

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Macrocycles based on magnetically functionalized zirconium oxide clusters

Malaestean, I. L. ; Kutluca, M. ; Speldrich, M. ; Ellern, A. ; Kögerler, P.FZJ*

2012
Elsevier New York, NY [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.ica.2011.08.061

Abstract: In the presence of 4,4'-bipyridine and Co(II) or Ni(II) groups, which are coordinatively constrained by bis-alkoxyamine chelating groups, dimeric [(Zr6O4)-O-IV(OH)(4)(RCOO)(12)](2) clusters rearrange to {Zr12O11(OH)(11)(RCOO)(16)} frameworks featuring highly condensed zirconium oxide cores. These {Zr-12} groups subsequently each coordinate to three M(II) groups and self-assemble via two bridging 4,4'-bpy into 2.6 nm {M6Zr24}type macrocycles of composition [M6Zr24O22(OH)(22)(C2H5COO)(40)(Hmdea)(2)(H(2)mdea)(4)(4,4'-bpy)(2)]. Surprisingly, two M(II) sites peripherally attached to the {Zr-12} frameworks adopt a rare eightfold coordination mode where the M2+ ions reside in a distorted square antiprismatic O7N environment. Magnetic measurements reveal that the zirconium oxide fragments efficiently mediate antiferromagnetic exchange between Ni2+ spin centers, whereas in case of the virtually isostructural Co2+ derivative pronounced ligand field asymmetry causes single-ion effects to significantly influence the low-field susceptibility data. (C) 2011 Elsevier B. V. All rights reserved.

Keyword(s): J ; Heterometallic complexes (auto) ; Magnetic properties (auto) ; Zirconium compounds (auto) ; Macrocycles (auto)

Note: Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. DE-AC02-07CH11358.

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Contributing Institute(s):

1. Elektronische Eigenschaften (PGI-6)

Research Program(s):

1. Grundlagen für zukünftige Informationstechnologien (P42)

Appears in the scientific report 2012

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Database coverage:
; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection ; Zoological Record

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