Polyenyl complex

The stability of the polyene complexes L toward dissociation is in general Jess iJian iJiat of polyenyl complexes h X. because the free polyene is usually... 

Mann, B.E. (1986) Fluxionality of polyene and polyenyl complexes. Chem. Soc. Revs., 15, 125. 

Polyenyl complexes the most common is cyclopentadienyl (Cp), usually pentahapto (sometimes mono- or trihapto) CsMcs (Cp ) stabilizes the complexes indenyl facilitates the trihapto mode. 

In general, coordination complexes of CO2, SO2, NO and other oxygen-containing ligands have strong bands. Polyene and polyenyl complexes, in general, do not give characteristic absorptions. 

In polyene and polyenyl complexes, carbons directly attached to the metal tend to be more shielded on binding, and a coordination shift (i.e., relative to the free ligand) of 25 ppm to high field is common. Metal nuclei with I = Vi show coupling to the metal in H and spectra. Diastereotopy also apphes in spectra and is seen for the diastereotopic F-Me carbons in 10.2. 

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