It is to be explained why IR spectroscopy does not distinguish very well between isomers I and J. It is to be explained how UV-vis spectroscopy could be used to distinguish between them. Concept introduction: In UV-vis spectroscopy, absorption of a photon promotes an electron from a lower-energy MO to a higher-energy MO. The λ max for the longest-wavelength absorption in the spectrum corresponds to the HOMO-LUMO. Conjugation decreases the energy difference between the HOMO-LUMO and thus increases the wavelength of the photon absorbed. IR spectroscopy enables to identify different functional groups in the given molecule. One of the greatest advantages of IR spectroscopy is that the frequency of a particular type of vibration is typically found within a characteristic range of frequencies, regardless of the functional group with which the vibration is associated. The fact that absorptions by certain vibrations appear with characteristic frequency ranges enables us to use IR spectroscopy to obtain structural information about a molecule.

Question

Want to see the full answer?

Answer 1

Question

Chapter 15, Problem 15.57P

Interpretation Introduction

Interpretation:

It is to be explained why IR spectroscopy does not distinguish very well between isomers I and J. It is to be explained how UV-vis spectroscopy could be used to distinguish between them.

Concept introduction:

In UV-vis spectroscopy, absorption of a photon promotes an electron from a lower-energy MO to a higher-energy MO. The λmax for the longest-wavelength absorption in the spectrum corresponds to the HOMO-LUMO. Conjugation decreases the energy difference between the HOMO-LUMO and thus increases the wavelength of the photon absorbed.

IR spectroscopy enables to identify different functional groups in the given molecule.

One of the greatest advantages of IR spectroscopy is that the frequency of a particular type of vibration is typically found within a characteristic range of frequencies, regardless of the functional group with which the vibration is associated. The fact that absorptions by certain vibrations appear with characteristic frequency ranges enables us to use IR spectroscopy to obtain structural information about a molecule.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Students have asked these similar questions

(4 pts - 2 pts each part) A route that can be taken to prepare a hydrophobic (water-repellent) aerogel is to start with trichloromethylsilane, CH3SiCl3 as the silicon source. a. What is the chemical reaction that this undergoes to form a product with Si-OH groups? Write as complete of a chemical equation as you can. CI CI-SI-CH3 CI b. The formation of a byproduct is what drives this reaction - what is the byproduct (if you didn't already answer it in part (a)) and how/why does it form?

b) Circle the substrate that would not efficiently generate a Grignard reagent upon reaction with Mg in ether. CI Br ד c) Circle the Grignard reagents that contain incompatible functional groups. MgBr HO MgBr MgBr MgBr MgBr HO MgBr

Q2: Predict all organic product(s), including stereoisomers when applicable. PCC OH a) CH2Cl2 Page 2 of 5 Chem 0310 Organic Chemistry 1 HW Problem Sets b) .OH Na2Cr2O7, H+ OH PCC CH2Cl2 c) OH