The compounds described in Problem 27 have very different ultraviolet spectra. One has max () =

The compounds described in Problem 27 have very different ultraviolet spectra. One has λ_max(ϵ) = 232(13,000) and 308(1450) nm, whereas the other has λ_max(ϵ) = 272(35,000) nm and a weaker absorption near 320 nm (this value is hard to determine accurately because of the intensity of the stronger absorption). Match the structures that you determined in Problem 27 to these UV spectral data. Explain the spectra in terms of the structures.

Data From Problem 27

The following spectroscopic data are for two carbonyl compounds with the formula C₈H₁₂O. Suggest a structure for each compound. The letter “m” stands for the appearance of this particular part of the spectrum as an uninterpretable multiplet. 

(a) ¹H NMR: δ = 1.60 (m, 4 H), 2.15 (s, 3 H), 2.19 (m, 4 H), and 6.78 (t, 1 H) ppm. ¹³C NMR: δ = 21.8, 22.2, 23.2, 25.0, 26.2, 139.8, 140.7, and 198.6 ppm. 

(b) ¹H NMR: δ =0.94 (t, 3 H), 1.48 (sex, 2 H), 2.21 (q, 2 H), 5.8 – 7.1 (m, 4 H), and 9.56 (d, 1 H) ppm. 13C NMR: d 5 13.6, 21.9, 35.2, 129.0, 135.2, 146.7, 152.5, and 193.2 ppm.