15. Analytical Techniques:IR, NMR, Mass Spect

The spectrum of trans-hex-2-enoic acid follows.

(a) Assign peaks to show which protons give rise to which peaks in the spectrum. (b) Draw a tree to show the complex splitting of the vinyl proton centered around 7 ppm. Estimate the values of the coupling constants.

Draw a splitting diagram for the Hb proton if Jbc = 10 and Jba = 5.

Draw a splitting tree, similar to Figures 13-32 and 13-33, for proton Hc in styrene. What is the chemical shift of proton Hc?

Draw the expected signal for a hydrogen with the following coupling constants. (a) Hₐ : δ 5.34 (Jₐ꜀ = 12 , Jₐ₆ = 2)

What coupling constant would you expect between Hₐ and H₆ in cyclopent-2-en-1-one?

Draw a diagram like the one shown in Figure 14.12 to predict b. the relative intensities of the peaks in a quintet.

Draw a splitting diagram for Hb, where a. Jba = 12Hz and Jbc = 6Hz.

Using a 60-MHz spectrometer, a chemist observes the following absorption: doublet, J = 7 Hz, at d 4.00 (a) What would the chemical shift (d) be in the 300-MHz spectrum? (b) What would the splitting value J be in the 300-MHz spectrum? (c) How many hertz from the TMS peak is this absorption in the 60-MHz spectrum? In the 300-MHz spectrum?