Infrared spectra cyclopentene

Ward (86) recorded an infrared spectrum of cyclopentene on Ni/SiOz in the vCH region. The absorptions at 2960 and 2875 cm 1 are consistent with the persistence of CH2 groups in a five-membered ring. Addition of hydrogen led to an intensified spectrum and to cyclopentane in the gas phase. 

Fig. 4.13. Far infrared spectrum of cyclopentene. P = 115 torr pathlength = 8 m. [Reproduced from Laane, J., Lord, R. C. J. Chem. Phys. 47, 4941 (1967).]...

The infrared data of LPDCPD indicate the presence of both acyclic >C=C< (cis and trans) and cyclic >C=C< moieties in the cyclopentene rings. The relative intensity of the IR absorption bands suggests that the polymer stereoconfiguration of the carbon-carbon double bonds is prevailingly cis. These results are also confirmed by the NMR spectrum. Assessments were made from off-resonance spectrum and signal intensity measurements.( Figure 3 )... 

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