INFLUENCE OF ELECTRONIC CONJUGATION AND STERIC EFFECTS ON THE CRYSTAL-STRUCTURES OF IMINO-DERIVATIVE AND HYDRAZIDO-DERIVATIVE OF FERROCENECARBALDEHYDE

The crystal and molecular structures of [Fe(C5H5)(C5H4CH=NC(6)H(4)X-p) ] (X = Br or F) have been determined. The two compounds have markedly different molecular conformations. These are compared with the structu res of two series of related ferrocenyl compounds and it is found that the major driving force for the molecular conformation is intra- rath er than inter-molecular interaction. The compounds all have electron-w ithdrawing C=N groups which have previously been shown to act as elect ron sinks. All the structures have bond lengths in keeping with this f inding. though a major steric interaction disguises some bond-length i nformation which would have shed more light on the overall electronic structure of the molecule. The value of Mossbauer spectroscopic data a s a complement to the X-ray structural findings is demonstrated.