A brief overview of the structural determination of cyclopentadienyliron arene complexes.

A review, with ∼9 refs., of the use of NMR spectroscopy for the detn. of the structure of a no. of cyclopentadienyliron arene systems. The examples presented here demonstrate the use of 1- and 2-dimensional NMR techniques in predicting the chem. structure and dynamics of these complexes. The numerous isomers obtained from the hydride addn. to mono- and dicyclopentadienyliron arene complexes were identified using 2-dimensional HH COSY and CH COSY. The 2-dimensional 1H COSY, DQ-COSY and NOE study of the ((η6-2,6-dimethylphenyl)(phenylsulfonyl)acetonitrile)-η5-cyclopentadienyliron cation showed that there is restricted rotation about the arene-methine C bond. 1-Dimensional NMR was also used for the detn. of the diastereomeric nature of the arene complexes, which arose from their complexation to the cyclopentadienyliron moieties, as well as in estg. the no. of repeating units in the oligomeric complexes