128B%20C13NMRspectra

128B%20C13NMRspectra - Element Nuclear spin quantum number...

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1 1 H 2 H 12 C 13 C 14 N 16 O 31 P 32 S Element Nuclear spin quantum number ( I ) Number of spin states 1/2 1 0 0 0 1/2 1 23 1 2 1/2 21 13 C-NMR Spectroscopy 12 C not magnetically active but 13 C has I = ½ ; its natural abundance is 1.1%; The sensitivity of 13 C is only 1/5700 of 1 H; this sensitivity problem is overcome with Fourier Transform (FT) NMR instrumentation (1970’s); Usually, the peak splitting due to couplings with protons are removed by broadband decoupling in a double resonance experiment; broadband decoupling can also enhance the 13 C signal intensity caused by the Nuclear Overhauser Effect (NOE) 13 C chemical shifts are reported relative to TMS; 300 MHz for 1 H-NMR = 75.5 MHz for 13 C-NMR; 10 mg in 0.5 mL of solvent in 5 mm tube
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2 It is customary to measure the resonance frequency (signal) of individual nuclei relative to the resonance frequency (signal) of a reference compound --- tetramethylsilane (TMS) Tetramethylsilane (TMS) CH 3 Si CH 3 CH 3 H 3 C Chemical shift ( Chemical shift ( δ ): the shift in ppm of an NMR signal from the signal of TMS
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This note was uploaded on 06/22/2010 for the course CHEM 128B taught by Professor Currie during the Spring '10 term at Concord.

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128B%20C13NMRspectra - Element Nuclear spin quantum number...

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