The structure of the monomeric oxygen adduct of vitamin B12r: A single crystal ESR study

✍ Scribed by E. Jörin; A. Schweiger; Hs.H. Günthard

• Publisher: Elsevier Science
• Year: 1979
• Tongue: English
• Weight: 409 KB
• Volume: 61
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(79)80632-6

✦ Synopsis

From ESR sir&e crystal spectra of Btzr 0 at -190JC_ThegaxtdACo 2 substituted in Btab the structure of the Co-O-O fragment was determined tensors were found to be non-coa-&rl with the foBowing principal values: gr = 1.994.ga = 3-013, ga = 2_0f9;_4~" = -31 MHz. AGo = -27 UHz. AC0 = -63 MHz_ The Co-O-O bond angle is 11 lo. Five-coordinated Co(!i) complexes show the ability to build cobalt oxygen adducts [I] _ The oxygen carrying properties of these compounds have been extensively studied with ESR in the Iast decade [2,S]_ Most of the studies on monomeric I:1 O,-Co(K) com-pIexes with reversibly bound dioxygen were accomplished in frozen solutions_ interpretation of the observed hypertine couplings leads to the conclusion that these complexes are formally best described as Co(IIi)-0, [2]_ Direct insight into the structure of the superoxo cobalt compleses by X-ray studies is only given in few eases [4] _ The reversible oxygenation of paramagnetic vita-