CHEM 212 Lecture Notes - Lecture 14: Lone Pair, Furan, Pyridine

• School: McGill University
• Department: Chemistry
• Course: CHEM 212
• Professor: Jean- Philip Lumb

Document Summary

There will be aromaicity with a proper bond arrangement o. Benzene c6h6: 4 units of unsaturaion: kekul structure 1 ring with 3 double bonds; alternaing double-single bond o all c-c bonds are equal in length. Molecules w/ e- s (p-orb) that can be delocalized over 3 sp2 hybridized atoms. 1. e- difusion cloud for every carbon with equal distance. Unsaturated monocyclic: aromaic planar; w/ p orbitals; w/ 4n+2 e"s, ani-aromaic potenially planar; 4n e"s, non-aromaic non-planar non-coninuous p orbitals. 2 h"s face directly against each other if placed planar -> thus non-planar. If unpaired in such a diagram, not aromaic! If lone pair is there, think about the re-hybridizaion! Pyridine nitrogen has one lone pair not in p-orb but in sp2. Furan oxygen has two lone pairs, one in p and another in sp2. Nitrogen"s lone pair can contribute to the aromaicity in this case (i. e. counted!)