Skip to main content
Ch. 15 - Structural Identification 2: Nuclear Magnetic Resonance Spectroscopy
Mullins - Organic Chemistry: A Learner Centered Approach 1st Edition
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoMullins 1st EditionCh. 15 - Structural Identification 2: Nuclear Magnetic Resonance SpectroscopyProblema 66a
Capitolo 14, Problema 66a

For the molecules in Assessment 15.58, give an approximate chemical shift for each indicated carbon. [The range of correct answers is large here.].
(a) Chemical structure of chlorobenzene with numbered carbons for NMR analysis: 1, 2, and 3.

Guida verificata passo dopo passo
1
Identify the type of carbon environment in the molecule. Consider factors such as hybridization (sp3, sp2, sp), the presence of electronegative atoms, and the degree of substitution.
Understand that chemical shift values in 13C NMR are influenced by the electronic environment around the carbon atom. Electronegative atoms or groups can deshield the carbon, leading to higher chemical shift values.
Consider the typical chemical shift ranges for different types of carbon environments: sp3 hybridized carbons generally appear between 0-50 ppm, sp2 hybridized carbons between 100-150 ppm, and sp hybridized carbons around 70-90 ppm.
Evaluate the effect of nearby functional groups or atoms. For example, carbons adjacent to oxygen or nitrogen atoms may experience a shift towards higher ppm values due to deshielding effects.
Estimate the chemical shift for each indicated carbon based on the identified factors and typical ranges. Remember that the range of correct answers is large, so focus on understanding the trends and influences rather than pinpointing an exact value.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Chemical Shift

Chemical shift refers to the resonant frequency of a nucleus relative to a standard in a magnetic field, typically measured in parts per million (ppm). In NMR spectroscopy, it provides insight into the electronic environment surrounding a nucleus, particularly carbon atoms in organic compounds. Variations in chemical shift can indicate different functional groups or hybridization states, making it essential for interpreting NMR spectra.
Video consigliato:
11:44
1H NMR Chemical Shifts

NMR Spectroscopy

Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful analytical technique used to determine the structure of organic compounds. It exploits the magnetic properties of certain nuclei, such as carbon-13, to provide information about the number and type of atoms in a molecule. By analyzing the chemical shifts and splitting patterns in the NMR spectrum, chemists can deduce the connectivity and arrangement of atoms within the molecule.
Video consigliato:
10:06
General NMR Features

Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. In organic chemistry, the presence of different functional groups can significantly influence the chemical shift observed in NMR spectroscopy. Understanding common functional groups, such as alcohols, ketones, and carboxylic acids, is crucial for predicting and interpreting the chemical shifts of carbon atoms in a given molecule.
Video consigliato:
02:36
Identifying Functional Groups
Pratica correlata
Domanda del libro di testo

Draw the 13C NMR spectrum you would expect to see for each of the molecules shown.

(b)

1283
views
Domanda del libro di testo

Draw the ¹H NMR spectrum you would expect to see for each of the molecules in Assessment 15.63.

(d)

1129
views
Domanda del libro di testo

Draw the ¹³C NMR spectrum you would expect to see for each of the molecules shown.

(a)

1417
views
Domanda del libro di testo

Draw the ¹H NMR spectrum you would expect to see for each of the molecules in Assessment 15.63.

(c)

1046
views
Domanda del libro di testo

Draw the ¹H NMR spectrum you would expect to see for each of the molecules in Assessment 15.63.

(b)

1164
views
Domanda del libro di testo

For the molecules in Assessment 15.58, give an approximate chemical shift for each indicated carbon. [The range of correct answers is large here.].

(c)

1032
views