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Closed Access item Co3(RL)2(hfac)6 ladder complex of 5-[4-(N-tert-Butyl-N-aminoxyl)phenyl]pyrimidine

Authors:Morón, M. Carmen
Palacio, Fernando
Issue Date:Feb-2006
Publisher:American Chemical Society
Citation:Inorganic Chemistry 45(6): 2562-2567 (2006)
Abstract:5-[4-(N-tert-butyl-N-aminoxyl)phenyl]pyridimine (4NITPhPyrim = RL) forms a 1-D ladder polymer complex with Co(hfac)2 of stoichiometry Co3(RL)2(hfac)6, having antiparallel [CoIIRL]n linear chains (rails) that are cross-linked by Pyrim−Co(hfac)2−Pyrim rungs. The magnetic behavior above 100 K is consistent with contributions from one high-spin CoII ion (the cross-link, S = 3/2) plus two Co−ON units with strongly antiferromagnetic (AFM) metal−radical exchange (each S = 1). The χT data show an AFM downturn as the temperature drops. Assuming weak exchange along chain portions of the polymer due to poor spin polarization across the phenyl−pyrimidine bond in RL, a linear three-spin (S = 1, 3/2, and 1) fit to the T > 18 K data yields an AFM cross-linker (rung) effective exchange of JCL/k = (−)5.3 K = (−)3.7 cm-1. Superexchange (σ-orbital overlap) is a likely mechanism for the effective AFM exchange between CoON and Co spin sites in the three-spin groupings.
Description:6 pages, 5 figures, 3 chart, 1 scheme, 2 tables.-- et al.
Publisher version (URL):http://dx.doi.org/10.1021/ic051884w
Appears in Collections:(ICMA) Artículos

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