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Resonance Raman studies of transition metal peroxo complexes: 7 —The peroxo‐dicobalt(III)‐ethylenediamine and L ‐histidine complexes
Author(s) -
Hester R. E.,
Nour E. M.
Publication year - 1981
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250110204
Subject(s) - ethylenediamine , raman spectroscopy , chemistry , resonance (particle physics) , diamine , spectral line , transition metal , crystallography , stereochemistry , analytical chemistry (journal) , inorganic chemistry , polymer chemistry , catalysis , physics , organic chemistry , astronomy , optics , particle physics
Resonance Raman spectra have been determined for the μ‐peroxo complex [(en) 2 CoO 2 Co(en) 2 ] 4+ and μ‐peroxo‐μ‐hydroxo complex [(en) 2 CoO 2 (OH)Co(en) 2 ] 3+ , where en = ethylenediamine. The spectra show bands at 799 and 795 cm −1 , assigned to the ν(OO) mode in each complex, respectively, while the ν(CoO) mode occurs at ∼590 cm −1 . However, two strong bands occur at 494 and 534 cm −1 in the spectrum of the μ‐peroxo complex and only one strong, broad band at 530 cm −1 occurs in the spectrum of the μ‐peroxo‐μ‐hydroxo complex. These are assigned to ν(CoN) modes in both complexes. The spectra of the complexes [( L ‐his) 2 CoO 2 Co( L ‐his) 2 ] and [( L ‐his) 2 CoO 2 (OH)Co( L ‐his) 2 ] − show bands at 811 and 805 cm −1 assigned to the ν(OO) mode, respectively, while the ν(CoO) mode is assigned at 600 and 590 cm −1 , respectively. The ν(CoN) modes in both complexes are assigned at 530 and 493 cm −1 . These bands are much stronger in the spectrum of the μ‐peroxo than in that of the μ‐peroxo‐μ‐hydroxo complexes. However, the obvious differences between the Raman spectra of the μ‐peroxo and μ‐peroxo‐μ‐hydroxo complexes are not in the ν(OO) and ν(CoO) bands but rather in the lower wavenumber ν(CoN) region. The ν(OO) band intensity excitation profiles demonstrate that the O 2 −2 →Co 3+ charge transfer transition occurs at ∼352 and 360 nm for [(en) 2 CoO 2 Co(en) 2 ] 4+ and [(en) 2 CoO 2 (OH)Co(en) 2 ] 3+ , respectively, and at 366 nm for the [( L ‐his)CoO 2 (OH)Co( L ‐his)] − complex.