Fünffach koordinierte Komplexe vom Typ [tripodM-(ortho-(X)(Y)C6H4)]n (X, Y = O, S) bei d5-, d6- und d7-systemen. synthese, struktur, elektrochemie und esr-spektren / Five-coordinate complexes [tripodM-(ortho-(X)(Y)C6H4)]n (X, Y = O, S) with d5-,d6- and d7-Systems. Synthesis, Structure, Electrochemistry and ESR-Spectra
Open Access
- 1 September 1994
- journal article
- research article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung B
- Vol. 49 (9) , 1183-1192
- https://doi.org/10.1515/znb-1994-0906
Abstract
The d6-Co(III)-species [tripodCo-(ortho-(X)(Y)C6H4)]+ (X, Y = O, S, tripod = CH3C(CH2PPh2)3) 1 are reversibly reduced to the neutral d7-Co(II)-compounds [tripodCo-(ortho-(X)(Y)C6H4)] (X, Y = O, S) 2. Both species show fivefold coordination of cobalt with coordination polyhedra in between the limits of the square pyramid and the trigonal bipyramid respectively. The low-spin d7-species 2 give clearly resolved ESR-spectra revealing the coexistence of two geometric isomers above -80 °C, with only one isomer persistent at temperatures around 100 K. As an analogous d5-system [benzyltripodFe-(ortho-(S)(S)C6H4)]+ 3 (benzyltripod = C6H5CH2C(CH2PPh2)3) has been obtained from [benzyltripodFe(NCCH3)3]2+ and C6H6S2. Alternatively complexes of this type, e.g. [tripodFe-(ortho-(S)(S)C6H4)]+ 4, may be prepared from Fe(H2O)6(BF4)2/tripod/C6H6S2 when the reaction mixture is activated by acidification with HBF4. The geometry of the d5-species 3 and 4 is close to a trigonal bipyramidKeywords
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