TY  - JOUR
AU  - Malaestean, I.L.
AU  - Kutluca, M.
AU  - Speldrich, M.
AU  - Ellern, A.
AU  - Kögerler, P.
TI  - Macrocycles based on magnetically functionalized zirconium oxide clusters
JO  - Inorganica chimica acta
VL  - 380
SN  - 0020-1693
CY  - New York, NY [u.a.]
PB  - Elsevier
M1  - PreJuSER-22478
SP  - 72 - 77
PY  - 2012
N1  - Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. DE-AC02-07CH11358.
AB  - 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.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000300180100010
DO  - DOI:10.1016/j.ica.2011.08.061
UR  - https://juser.fz-juelich.de/record/22478
ER  -