2024-03-28T15:35:08Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/197652016-02-16T06:09:08Zcom_10261_31com_10261_3col_10261_284
2009-12-21T13:51:10Z
urn:hdl:10261/19765
Co3(RL)2(hfac)6 ladder complex of 5-[4-(N-tert-Butyl-N-aminoxyl)phenyl]pyrimidine
Field, Lora M.
Morón, M. Carmen
Lahti, Paul M.
Palacio, Fernando
Paduan-Filho, A.
Oliveira, Nei F. Jr.
National Institutes of Health (US)
Comisión Interministerial de Ciencia y Tecnología, CICYT (España)
Fundação de Amparo à Pesquisa do Estado de São Paulo
University of Massachusetts
6 pages, 5 figures, 3 chart, 1 scheme, 2 tables.
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.
2009-12-21T13:51:10Z
2009-12-21T13:51:10Z
2006-02
artículo
Inorganic Chemistry 45(6): 2562-2567 (2006)
0020-1669
http://hdl.handle.net/10261/19765
10.1021/ic051884w
1520-510X
http://dx.doi.org/10.13039/100000002
http://dx.doi.org/10.13039/501100007273
http://dx.doi.org/10.13039/501100001807
http://dx.doi.org/10.13039/100007919
eng
http://dx.doi.org/10.1021/ic051884w
Sí
closedAccess
American Chemical Society