Question

At certain radio frequency (r.f) pulse field strength B_1, if the^1 H 90 degree pulse length = 12.8 mu s, what is its 45 degree pulse length? ___. iii) Assuming we measured^1H 90 degree pulse length = 12.8 mu s at certain r.f. pulse field strength b_1. If we decrease the pulse strength B_1 to only half of the original pulse field strength, what is the 90 degree pulse length now? ___. In lab 9, we measured^1H NMR spectrum and T_1 relaxations for 1-butanol sample, Ch_3 CH_2 CH_2 CH_2 OH. Use the spectra to answer the following questions. (a) (b) (c) List the chemical shifts of^1H at these sites: CH_3:___ ppm; CH_2 (a): _____ppm, CH_2 (b): ___ ppm; CH_2 (c): ___ ppm; OH: ___ ppm. ii) From the fine structure i.e. peak splitting, the J-coupling of^1H at CH_3 or CH_2 sites can be determined as about___ppm, and ___Hz. iii) At which site, there is the strongest^1H nuclear shielding sigma? ___ At which site, there is the weakest^1H nuclear shielding sigma? ____(a) CH_3 site (b) CH_2 (a) site (c) CH_2 (b) site (d) ch_2 (c) site (e) OH site

Answer 1