CHAPTER 3.1: NMR QUESTION 1 A compound has the molecular formula C,H,O,Br. a) Draw the structures of three possible isomers with the structure of RCOR'. (3 marks) b) Match the 'H NMR data P, Q and R below with the correct isomer and assign the correct chemical shift to each non-equivalent proton of each isomer. Data Spectrum P Proton Chemical shift integration multiplicity A 1.03 3 triplet B 2.05 2 quintet 4.50 1 triplet D 10.97 1 singlet Data Spectrum Q 000 Proton B Chemical shift integration 1.14 3 2.29 2 6.09 2 multiplicity triplet quartet singlet Data Spectrum R Proton A B D <.00 chemical shift integration multiplicity triplet singlet sextet nn marks question a in nmr spectroscopy explain and illustrate the phenomena of diamagnetic shielding by valence electrons. b define mark c clearly how following factors affects i electronegative elements ii anisotropic effect pi bond. terms: auxochromes base peak briefly influences benzene. spectrum compound x is shown below with for each signal. label protons on structure x. describe signals b. proton ch ch2 ch3>