Vinyl group spectra

The observation of the spectrum for styrene polymerized on the surface of silane-treated silica and of the difference spectrum of polystyrene adsorbed on the surface of silica have revealed that there are absorption bands of atactic polystyrene at 1602, 1493, 1453, 756, and 698 cm. The absorption bands at 1411 and 1010 cm are related to vinyl trimethoxy silane, and C of the difference spectrum is below the base line. This indicates that the vinyl groups of silane react with styrene to form a copolymer. 

The spectrum of divinyl-P,P -thiodipropionate is shown in Figure 9.49. The typical ABX pattern at lowfield is related to the vinyl group, the four peaks at 57.2 corresponding to the X proton. The geminal A and B protons are well separated between 54.5 and 65.0 and the symmetrical but complex A2B2... 

The VEEL spectrum of a surface vinyl group derived from low-temperature decomposition of vinyl iodide on Pt(lll) has been reported with features at 2920 cm 1 (s), eCH 1600 cm 1 (w), vCC 1380 cm-1 (m), 8= CH2 scissors 1255 cm1 (mw), <5C=CH 955 cm 1 (s), -y=CH2 and 690 cm 1 (mw), y=CH2 twist (208). The strength of the out-of-plane y = CH2 mode shows that the plane of the vinyl group is more nearly parallel than perpendicular to the surface, probably o--bonded to one metal atom and 77-bonded to another. This inference is confirmed by the relatively low wavenumbers of the eCH modes. However, in such a situation, the vCC wavenumber... 

Fig. 13. Proton NMR spectrum at 220 Me of cyanoferriprotoporphyrin IX. The distinction between resonances o and d is arbitrary. In the resonances of the 2,4-vinyl groups (/ and g) the fine-structure from proton-proton spin-spin coupling is partially resolved...

The 13C NMR spectrum reveals that the four carbon atoms of the molecule are contained in one each of the fragments CH3, CH2, and CH, along with the carbonyl carbon. In addition to the two carbons of the acetate group, the remaining two carbons are the CH2 and CH carbons of a vinyl group, CH=CH2. Compound A is vinyl acetate. 

---