Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 14: Q.21558-14-49P (page 563)

Question: Rank the highlighted carbon atoms in each compound in order of increasing chemical shift.

a.

b.

Short Answer

Expert verified

Answer

a. Ca< Cb < Cc

b. Cc < Cb< Ca

Step by step solution

01

Chemical shift

13C spectroscopy gives a downfield (higher value) chemical shift and an upfield chemical shiftaccording to the non-equivalent chemical environment present around the atom which is under observation.

02

Explanation

a.

Labeled carbon

Ccis adjacent to the carbonyl oxygen which is an electronegative atom. Therefore, Cc has higher value of chemical shift. Cb is also close to carbonyl oxygen followed by Ca.

Therefore, the order of chemical shift value is shown as:

a. Ca < Cb < Cc

b.

Labeled carbon

Cahas higher value of chemical shift due to presence of sp2 hybridized atoms. Ccis adjacent to Br which is an electronegative atom. Therefore, CC has higher value of chemical shift. Cb is also close to the double bond.

Therefore, the order of chemical shift value is shown as:

b. Cc < Cb < Ca

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Question. In the presence of a small amount of acid, a solution of acetaldehyde(CH3CHO) in methanol (CH3OH) was allowed to stand and a new compound L was formed. L has a molecular ion in its mass spectrum at 90 and IR absorptions at 2992 and 2941cm-1 . L shows three signals in its 13C-NMR at 19, 52, and 101 ppm. 1H-NMR spectrum of L is given below. What is the structure of L?

Question: Cyclohex-2-enone has two protons on its carbon-carbon double bond (labeled Ha and Hb ) and two protons on the carbon adjacent to the double bond (labeled Hc ). (a) If Jab = 11 Hz and Jbc = 4 Hz, sketch the splitting pattern observed for each proton on the hybridized carbons. (b) Despite the fact that Ha is located adjacent to an electron-withdrawing C=O, its absorption occurs up-field from the signal due to Hb(6.0 vs. 7.0 ppm). Offer an explanation.

The 1H NMR spectrum of CH3OH recorded on a 500 MHz NMR spectrometer consists of two signals, one due to the CH3 protons at 1715 Hz and one due to the OH proton at 1830 Hz, both measured downfield from TMS. (a) Calculate the chemical shift of each absorption. (b) Do the CH3 protons absorb upfield or downfield from the OH proton?

How many signals are present in the 1HNMR spectrum for each molecule? What splitting is observed in each signal?

a.

b.

c.

What splitting pattern is observed for each proton in the following compounds?

a.

b.
See all solutions

Recommended explanations on Chemistry Textbooks

Chemical Analysis

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Chemistry Branches

Read Explanation

Kinetics

Read Explanation

Inorganic Chemistry

Read Explanation

Making Measurements

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free