Skip to main content
Ch. 16 - Aromatic Compounds
Wade - Organic Chemistry 9th Edition
Wade9th EditionOrganic ChemistryISBN: 9780135213728Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoWade 9th EditionCh. 16 - Aromatic CompoundsProblema 34d,e
Capitolo 16, Problema 34d,e

Each of the following heterocycles includes one or more nitrogen atoms. Classify each nitrogen atom as strongly basic or weakly basic, according to the availability of its lone pair of electrons.
(d)
(e)

Guida verificata passo dopo passo
1
Step 1: Analyze the structure of heterocycle (i). Identify the nitrogen atoms and determine whether their lone pairs are involved in resonance or conjugation with the aromatic ring. Lone pairs involved in resonance are less available for protonation, making the nitrogen weakly basic.
Step 2: For heterocycle (i), classify the nitrogen atom in the imine group (double-bonded nitrogen) as weakly basic because its lone pair is part of the conjugated system and contributes to the aromaticity of the ring.
Step 3: For heterocycle (i), classify the nitrogen atom in the amine group (single-bonded nitrogen) as strongly basic because its lone pair is not involved in resonance and is readily available for protonation.
Step 4: Analyze the structure of heterocycle (ii). Identify the nitrogen atoms and determine whether their lone pairs are involved in resonance or conjugation with the aromatic ring. Lone pairs involved in resonance are less available for protonation, making the nitrogen weakly basic.
Step 5: For heterocycle (ii), classify the nitrogen atom in the pyridine-like structure as weakly basic because its lone pair is part of the conjugated system. The nitrogen atom in the amine group (single-bonded nitrogen) is strongly basic because its lone pair is not involved in resonance and is readily available for protonation.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
12m

Concetti chiave

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

Basicity of Nitrogen Atoms

The basicity of nitrogen atoms in heterocycles is determined by the availability of their lone pair of electrons for protonation. Strongly basic nitrogen atoms have lone pairs that are readily available for bonding with protons, while weakly basic nitrogen atoms have lone pairs that are less accessible due to resonance or steric hindrance.
Video consigliato:
Percorso guidato
1:45
Nitrogenous Bases Concept 3

Resonance Effects

Resonance occurs when electrons are delocalized across multiple atoms, which can stabilize a molecule. In heterocycles, if a nitrogen atom participates in resonance with adjacent double bonds, its lone pair may be involved in resonance structures, reducing its availability for protonation and thus its basicity.
Video consigliato:
03:32
Understanding Resonance Effects

Aromaticity and Basicity

Aromatic compounds are cyclic, planar structures with a ring of resonance that follow Huckel's rule. The presence of nitrogen in an aromatic system can influence basicity; nitrogen atoms that contribute to the aromatic system may have their lone pairs involved in maintaining aromaticity, making them less basic compared to non-aromatic nitrogen atoms.
Video consigliato:
06:21
Understanding the difference between basicity and nucleophilicity.
Pratica correlata
Domanda del libro di testo

Some of the following compounds show aromatic properties, and others do not.

1. Predict which ones are likely to be aromatic, and explain why they are aromatic.

2. Predict which nitrogen atoms are more basic than water and which are less basic.

(d)

675
views
Domanda del libro di testo

The following molecules and ions are grouped by similar structures. Classify each as aromatic, antiaromatic, or nonaromatic. For the aromatic and antiaromatic species, give the number of pi electrons in the ring.

(g)

522
views
Domanda del libro di testo

Some of the following compounds show aromatic properties, and others do not.

1. Predict which ones are likely to be aromatic, and explain why they are aromatic.

2. Predict which nitrogen atoms are more basic than water and which are less basic.

(e)

484
views
Domanda del libro di testo

Some of the following compounds show aromatic properties, and others do not.

1. Predict which ones are likely to be aromatic, and explain why they are aromatic.

(a)

(b)

(c)

1267
views
Domanda del libro di testo

Each of the following heterocycles includes one or more nitrogen atoms. Classify each nitrogen atom as strongly basic or weakly basic, according to the availability of its lone pair of electrons.

(a)

(b)

(c)

1425
views
Domanda del libro di testo

The following molecules and ions are grouped by similar structures. Classify each as aromatic, antiaromatic, or nonaromatic. For the aromatic and antiaromatic species, give the number of pi electrons in the ring.

(d)

159
views