Crystal and molecular structure of tricarbonyl-π-[1,1,1-tricarbonyl-2-methyl-3-diphenylmethylene-6-methoxyferra-2-oxacyclohexenyl]iron(Fe–Fe), a product from the reaction between diphenyldiazomethane and tricarbonyl-π-[1,1,1-tricarbonyl-2,5-dimethoxyferracyclopentadiene]iron

The crystal and the molecular structure of the title compound (2) have been determined by X-ray diffraction methods from photographic data. Crystals are monoclinic prisms, space group P21/c, with Z= 4 in a cell with a= 11·76, b= 17·60, c= 13·66 A, β= 119·2°. The structure was solved by Patterson and Fourier methods and refined by least-squares techniques to R 0·138 for 1527 reflections. Both iron atoms have distorted octahedral co-ordination. The C–C bond lengths in the π-allyl system are 1·38 and 1·44 A, and the mean C–Fe distance to this system is 2·08 A. Fe–Fe distance is 2·62 A. The structure possesses a dative bond from oxygen to iron of 2·07 A.