A SSIGNMENT OF S PIN S YSTEMS NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy1 For each compound: Describe all spin systems Determine the number of protons that are: Chemical shift equivalent Magnetic equivalent Enantiotopic Diastereotopic

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy2 MW 114 MW 116

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy3 MW 169 has -Br MW 150

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy4 MW 100 MW 74

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy5 MW 73 MW 56

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy6 MW 89 MW 138

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy7 MW 122 MW 102

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy8 MW 113 MW 94

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy9 MW 152 MW 157 has -Cl

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy10 MW 208 MW 98

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy11 MW 126 MW 116

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy12 MW Cl MW 122

S PLITTING OF S IGNALS – S TRUCTURE DETERMINATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy13 MW 96

P RACTICE WITH P OPLE N OTATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy14 On graph paper, draw a schematic (line) representation of the pure first- order spectrum AMX 3 corresponding to the following parameters: (Hz from TMS): A = 80; M = 220; X = 320 J (Hz): J AM = 10; J AX = 12; J MX = 0 Assume spectrum is a pure 1 st order spectrum and ignore small distortions in relative intensities that would occur in a ‘real’ spectrum. Sketch in “splitting diagrams” above the schematic spectrum to indicate which splittings correspond to which coupling constants. Give the shifts on the  scale corresponding to the above spectrum on a 60 MHz NMR ( 1 H).

P RACTICE WITH P OPLE N OTATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy15 AMX 3 (Hz from TMS): A = 80; M = 220; X = 320 J (Hz): J AM = 10; J AX = 12; J MX = 0

S TRUCTURE D ETERMINATION WITH P OPLE N OTATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy16 The 400 MHz 1H NMR spectrum of one of the following isomeric hydroxycinnamic acids is given below. Which one is it? Justify your answer based on chemical shift and coupling constants.

S TRUCTURE DETERMINATION WITH P OPLE N OTATION NMR - The Coupling Constant 4-1 CHEM 430 – NMR Spectroscopy17