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X-ray structure and spectroscopic characterization of divalent dinuclear cobalt complexes containing carboxylate- and phosphodiester- auxiliary bridges
Gnana Sutha Siluvai,
Published in
Volume: 362
Issue: 9
Pages: 3119 - 3126
Two dinuclear spin-coupled divalent cobalt complexes, [Co2(P1-O)(μ2-OAc)](ClO4)2, (1) and [Co2(P1-O)(μ2-BNPP)](ClO4)2, (2) containing μ-1,3 acetate (OAc) and bis(4-nitrophenyl)phosphate (BNPP) auxiliary bridges, respectively, were synthesized by the reaction of a classic dinucleating ligand, P1-OH with cobalt(II) perchlorate in presence of acetic acid/bis(4-nitrophenyl)phosphate. They were characterized by single crystal X-ray diffraction, to show a trigonal bipyramidal geometry around each cobalt center and the intervening bridging atoms that are responsible for spin-transfer between the two divalent cobalt centers; the alkoxo oxygen donor occupies an equatorial position, and the auxiliary ligand oxygens (OAc/BNPP) occupy the axial positions. Solution state magnetic moment measurement together with UV-Vis/NIR spectra revealed a high-spin ground state (S = 3/2) for Co(II) in these compounds. Complexes 1 and 2 show interesting 1H NMR spectral features of resonances with relatively narrower linewidths in conjunction with a sizable chemical shift dispersion of -5 and 265 ppm. Complex 2 containing the bis(4-nitrophenyl)phosphate auxiliary bridge showed narrower spectral window than complex 1 that has the acetate auxiliary bridge. © 2009 Elsevier B.V. All rights reserved.
About the journal
JournalInorganica Chimica Acta
Open AccessNo