prov:value
| - atom belonging to the group consisting of Fe, Co, Ni, Cu, Zn, Pd and Pt, R1 and R2 independently of one another are a hydrogen atom or alkyl, cycloalkyl, aryl, aralkyl, alkaralkyl or acyl each of which is unsubstituted or substituted, R3, R4, R5 and R6 independently of one another are a hydrogen atom, alkyl, alkoxy, alkylthio and alkoxycarbonyl having 1 to 8 C atoms, aryloxy or halogen, or R3 and
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