Cooperative electron delocalization effects

Scheme 18.1 Cooperative electron delocalization effects between Eu and Fe in EuFeOs perov-skite for total oxidation of toluene. (Reprinted with permission from Ref. [25]. Copyright 2014, Elsevier.)...

Bretta F. King and F. Weinhold, Structure and spectroscopy of (HCN)n clusters Cooperative and electronic delocalization effects in C H N hydrogen bonding. J. Chem. Phys. 103, 333 347 (1995). 

The bridging of two or more metallocene units is of great interest with regard to the potential for electronic interaction between the metal centres. Cooperative effects may be observed as the result of electronic transmission through the bridge or by direct metal-metal interaction . New physical and chemical properties can be envisaged. In partially oxidized or reduced polymetallocenes, different kinds of mixed-valence behaviour are expected. The properties of such mixed-valence compounds will depend on the amount of delocalization, i.e. on the extent of interaction between the metallocene centres involved (class I,n or in according to Robin and Day ). 

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