It is to be shown that Frost's circle could be adapted to generate the orbital energy level diagram shown for cyclopentadienyl anion. Concept introduction: The number of π electrons for a given polyene cation are first determined. These π electrons are assigned to the molecular orbitals in accordance with the rule that states that the lowest energy orbitals fill first and the maximum number of electrons in one orbital is two. In case of the two orbitals having comparable energies, each gets one electron before either orbital gets two. Frost's circle is used to set up the Huckel's molecular orbitals of planar, monocyclic, and completely conjugated polyenes. The energy levels can be superimposed on a polygon with appropriate sides with the vertex pointing down. By inscribing a polygon having appropriate number of sides within a circle so that one of its corners lies at the bottom, each of the polygon's corners defines a π electron energy level. A horizontal dotted line drawn through the center of the circle separates the bonding and anti-bonding molecular orbitals. The bonding orbitals are shown by the vertices below the halfway mark of the circle. The antibonding orbitals are shown by the vertices above the halfway mark. If the vertices lie exactly in the middle, then they represent non-bonding orbitals.

Question

Want to see the full answer?

Answer 1

Question

Chapter 12.20, Problem 26P

Interpretation Introduction

Interpretation:

It is to be shown that Frost's circle could be adapted to generate the orbital energy level diagram shown for cyclopentadienyl anion.

Concept introduction:

The number of π electrons for a given polyene cation are first determined.

These π electrons are assigned to the molecular orbitals in accordance with the rule that states that the lowest energy orbitals fill first and the maximum number of electrons in one orbital is two. In case of the two orbitals having comparable energies, each gets one electron before either orbital gets two.

Frost's circle is used to set up the Huckel's molecular orbitals of planar, monocyclic, and completely conjugated polyenes.

The energy levels can be superimposed on a polygon with appropriate sides with the vertex pointing down.

By inscribing a polygon having appropriate number of sides within a circle so that one of its corners lies at the bottom, each of the polygon's corners defines a π electron energy level.

A horizontal dotted line drawn through the center of the circle separates the bonding and anti-bonding molecular orbitals.

The bonding orbitals are shown by the vertices below the halfway mark of the circle. The antibonding orbitals are shown by the vertices above the halfway mark. If the vertices lie exactly in the middle, then they represent non-bonding orbitals.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Students have asked these similar questions

Some of the theories used to describe interface structure can be distinguished by:1. the measured potential difference.2. the distribution of ions in solution.3. the calculation of charge density.4. the external Helmoltz plane.

When talking about the acidity of carboxylic acids, is it the same thing to say higher or stronger acidity?

Using the following two half-reactions, determine the pH range in which $NO_2^-\ (aq)$ cannot be found as the predominant chemical species in water.* $NO_3^-(aq)+10H^+(aq)+8e^-\rightarrow NH_4^+(aq)+3H_2O(l),\ pE^{\circ}=14.88$* $NO_2^-(aq)+8H^+(aq)+6e^-\rightarrow NH_4^+(aq)+2H_2O(l),\ pE^{\circ}=15.08$