Answer to Question #85851 in Organic Chemistry for anuj

Question

Compare the basicities of pyridine and pyrrole

Answer 1

Pyrrole is an aromatic molecule: 6 electrons contribute into 6π-electron system of pyrrole (4 electrons of carbon atoms and a lone pair of nitrogen atom). Basidity of pyrrole is determied by the ability of nitrogen atom to share it's lone pair to form a bond. As this lone pair is involved in 6π-electorns aromatic system of pyrrole then nitrogen atom is unavalibe to donate it's lone pair. Pyrrole is a weak base.

Pyridine is an aromatic molecule too: 6 electrons contribute into 6π-electorn aromatic system of pyridine (5 electrons of carbon atoms and one electron of nitrogen atom). Baisidty of pyridine is determied by the ability of nitrogen atom to share it's lone pair to form a bond. This lone pair is not involved in 6π-electorns aromatic system of pyridine then nitrogen atom is avalibe to donate it's lone pair. Pyridine is more strong base than pyrrole.