An explanation as to why three singlets of equal intensity appear at − 60 ° C while the two singlets appear at 36 ° C with the intensity ratio of 2 : 1 for the methyl groups of isopropylmesitylene is to be stated. Concept introduction: Many nuclei and electrons have spin. Due to this spin magnetic moment arises. The energy of this magnetic moment depends on the orientation of the applied magnetic field. In NMR spectroscopy, every nucleus has a spin. There is an angular momentum related to the spin. The difference between its resonance frequency and that of the reference standard is known as the chemical shift of a nucleus. Tetramethylsilane (TMS) is taken as reference.

Question

Want to see the full answer?

Answer 1

Question

Chapter 16, Problem 16.67AP

Interpretation Introduction

Interpretation:

An explanation as to why three singlets of equal intensity appear at −60 °C while the two singlets appear at 36 °C with the intensity ratio of 2:1 for the methyl groups of isopropylmesitylene is to be stated.

Concept introduction:

Many nuclei and electrons have spin. Due to this spin magnetic moment arises. The energy of this magnetic moment depends on the orientation of the applied magnetic field. In NMR spectroscopy, every nucleus has a spin. There is an angular momentum related to the spin. The difference between its resonance frequency and that of the reference standard is known as the chemical shift of a nucleus. Tetramethylsilane (TMS) is taken as reference.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Students have asked these similar questions

3. Refer to the data below to answer the following questions: Isoelectric point Amino Acid Arginine 10.76 Glutamic Acid 3.22 Tryptophan 5.89 A. Define isoelectric point. B. The most basic amino acid is C. The most acidic amino acid is sidizo zo

3. A gas mixture contains 50 mol% H2 and 50 mol% He. 1.00-L samples of this gas mixture are mixed with variable volumes of O2 (at 0 °C and 1 atm). A spark is introduced to allow the mixture to undergo complete combustion. The final volume is measured at 0 °C and 1 atm. Which graph best depicts the final volume as a function of the volume of added O2? (A) 2.00 1.75 Final Volume, L 1.50 1.25 1.00 0.75 0.50 0.25 0.00 0.00 0.25 0.50 2.00 (B) 1.75 1.50 Final Volume, L 1.25 1.00 0.75 0.50- 0.25 0.00 0.75 1.00 0.00 0.25 Volume O₂ added, L 2 0.50 0.75 1.00 Volume O₂ added, L 2 2.00 2.00 (C) (D) 1.75 1.75 1.50 1.50 Final Volume, L 1.25 1.00 0.75 0.50 Final Volume, L 1.25 1.00 0.75 0.50 0.25 0.25 0.00 0.00 0.00 0.25 0.50 0.75 1.00 0.00 0.25 Volume O₂ added, L 0.50 0.75 1.00 Volume O₂ added, L 2

Leucine is an essential amino acid with the systematic name 2-amino-3-methylpentanoic acid. It has pai 2.36 and pKa2 = 9.60. H2N-C(R)H-COOH and R is -CH2-CH(CH3)2 A. Draw the condensed structure for leucine, and label all chirality centers with an asterisk. B. How many possible stereoisomers of leucine are there? C. Draw a Fischer projection of L-leucine and label the chirality center(s) as R or S. D. What is the p/ of leucine? E. Draw the structure of the predominant form of leucine at 10.00. F. Draw the structure of the predominant form of leucine at pH = 1.50. G. Leucine is described as an essential amino acid. What does this mean? H. Show the alkyl halide you would use to prepare leucine by the amidomalonate method. =