Vibrational spectra allyl group

Allyl bromide reacts with Rh(TTP) in acetonitrile to form bright yellow [(o-C3H5)Rh(TTP)Br]PF6. Its molar conductance (160 cmV ohm mole) confirms the electrolyte type (1 1), and the IR spectrum has a weak but well defined band at 1618 cm that is assignable (41) to the C=C stretching vibration of a (r-bonded allyl group. In addition, the band typical of tt allylic structures in the 500-520 cm" region is not observed. Limited solubility prevented NMR studies. 

The first allyl derivative of a rare earth was the complex dicyclopentadienyl allyl scandium, prepared by Coutts and Wailes (1970) from dicyclopentadienyl scandium chloride and allyl magnesium chloride in benzene-tetrahydrofuran. The orange compound shows an NMR spectrum with a singlet for the cyclopentadienyl protons at 5.90 ppm, and a quintet at 7.29 and a doublet at 3.05 ppm for the fluxional allyl group. The fluxional allyl group is also implicated by the IR band at 1475 cm for a delocalized C—C stretching vibration. 

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