Following are spectroscopic and other data for several compounds. Propose a structure for each of them. 

(a) Molecular formula = C₆H₄Br₂. ¹H NMR spectrum A. ¹³C NMR: 3 peaks. IR: v˜ = 745 (s, broad) cm^-1. UV: λmax(ε) = 263(150), 270(250), and 278(180) nm. 

(b) Molecular formula 5 C₇H₇BrO. ¹H NMR spectrum B. ¹³C NMR: 7 peaks. IR: v˜ = 765(s) and 680(s) cm^-1. 

(c) Molecular formula = C₉H₁₁Br. ¹H NMR spectrum C. ¹³C NMR: δ = 20.6 (CH₃), 23.6 (CH₃), 124.2 (C_quaternary), 129.0 (CH), 136.0 (C_quaternary), and 137.7 (C_quaternary) ppm.

Transcribed Image Text:

1Η ΝMR 2 H 2 H TT 7.6 7.2 7.1 (CH3)4Si 1Η ΝMR 3 H 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 300-MHz 'H NMR spectrum ppm (8) A 7.2 7.1 7.0 6.9 6.8 3 H (CH3)4Si 1 H 10.09.59.08.58.07.57.06.56.05.55.04.54.03.53.02.52.01.51.00.50.0 300-MHz 'H NMR spectrum ppm (8) 6 H