Chapter 19.SE, Problem 29VC

Interpretation Introduction

Interpretation:

The molecular model of the enamine prepared from acetone and dimethylamine is given. a) The geometry and hydridization of the N atom are to be shown. b)The orbital of nitrogen that holds the lone pair of electrons is to be identified. c) The geometric relationship between the p orbitals of the double bond and the nitrogen orbital that holds the lone pair is to be stated. Why this geometry represents minimum energy is to be explained.

Concept introduction:

Primary amines react with aldehydes and ketones to yield imines R₂C=NR while secondary amines react to yield enamines R₂NCR=CR₂. Nitrogen normally uses sp³ hydridized orbitals for bonding. The N atom has pyramidal structure.Resonance delocalization will minimize the energy of the molecules sand make them more stable.

To show:

The geometry and hydridization of the N atom in the enamine.

To identify:

The orbital of nitrogen that holds the lone pair of electrons.

To explain:

The geometric relationship between the p orbitals of the double bond and the nitrogen orbital that holds the lone pair and to explain why this geometry represents minimum energy.