Chemie polyfunktioneller Moleküle, 132. Mitt. [1]. Synthese und Kristallstruktur paramagnetischen fünffach-koordinierten eines Cobalt(III)-Komplexes ausgehend von Co2(CO)8, Ph2P-N*PPh2-PPh2*N-PPh2 und Lufta

The reaction of Co2(CO)8 and Ph2P-N*PPh2-PPh2*N-PPh2 (1) in a molar ratio between 1:1 and 1:3 in toluene always leads to the formation of both the yellow by-product [fac-Co(CO)3(Ph2P-N*PPh2-PPh2*N-PPh2-P,P′)] [Co(CO)4] (4) and the red compound [(Co)2(μ-CO)(CO)4(μ-Ph2P-N-PPh2)2] (5) that has already been characterized by spectroscopic data and X-ray analysis. Whereas 4 is obtained as a precipitate, the red compound 5 stays in solution and reacts in presence of air with the remaining ligand 1 in a non-stoichiometrical reaction to the violet cobalt(III) complex [Co(η1-O-PPh2*N-PPh2*O)(η2-O-PPh2*N-PPh2*O)2] (6). The crystal structure of 6 proves a distorted trigonal bipyramidal coordination of the oxygen atoms at the Co(III) ion. Surprisingly, complex 6 shows an unusual paramagnetism according to four unpaired electrons (5.21±0.04 BM).