Question

Work on how to calculate molecular formula for percentages. Also how to calculate the degree of unsaturatuon.

From the MS, IR, 'H-NMR, and "C-NMR provided, please identify the organic compound. Because you are able to take this home, you must now solve the structure and label each IR H-NMR, and "C-NMR unambiguously. If you need a review, I have already posted spectroscopy materials from CHM235. Please utilize those handouts and let me know if you have any questions regarding the interpretation of my handouts How to tackle the problem 1. Interpret the MS- figure out the molecular formula and calculate the degrees of unsaturation in the compound Interpret the IR- circle and label major peaks on the IR provided. Interpret the 'H-NMR -identify each resonance unambiguously. For example, draw out the structure and label H's a, b, c. Then label each resonance unambiguously Interpret the "C-NMR - identify each resonance unambiguously. For example, draw out the structure and label C's I,2,3. Then label each resonance accordingly 2. 3. 4. "Please draw out the skeletal structure on each page. Good luck! " In the l"C NMR, there are three lines very close together at 77ppm. Those are solvent peaks (CDC). ms %H-3.3% Go- 20 50 125 150 m/z I2

Answer 1

The given organic compound contains 55.6% C and 3.3% of H. Thus 100g of the compound will contain 55.6g of C and 3.3 g of H. Hence number of moles C in 55.6 g of C 55.6/124.63 number of moles H in 3.3 g of H 3.3/1.008 3.27 To get simplest ratio, of both elements, divide the number of moles of each elements by smallest value 3.27 to get empirical formula as 4.63/3.27 3.27/3.27 or C3H2 From mass data, the m/z- 152 Hence, molecular formula is C12Ha hence the structure for compound can be given as symmetry tt... symmetry Chemical Formula: C12Hg due to symmetry, it will give only two signals in 1HNMR and three signals in 13CNMR data Degree of unsaturation(a+ 1) (b -c+f) 2 Where a number of Carbon atoms, bnumber of Hydrogen atoms, cnumber of Nitrogen atoms f number of Halogen atoms For C12Hs Degree of unsaturation (121) (8)/2 Degree of unsaturation 13 -4 Degree of unsaturation9