Show the relative energy levels of the seven πmolecular orbitals of the cycloheptatrienyl system

step 1 Solving problem 45 of chapter 15. So we need to draw the structure of the cyclo -epta -triening

Show the relative energy levels of the seven πmolecular...

Show the relative energy levels of the seven $\pi$ molecular orbitals of the cycloheptatrienyl system. Tell which of the seven orbitals are filled in the cation, radical, and anion, and account for the aromaticity of the cycloheptatrienyl cation.

Key Concepts

Molecular Orbital Theory

Molecular Orbital Theory is a framework for understanding the distribution of electrons in molecules. It describes electrons as occupying molecular orbitals that are spread over the entire molecule rather than localized between atoms, and it predicts the bonding, antibonding, and nonbonding characteristics of these orbitals.

? Molecular Orbitals

? Molecular Orbitals are formed by the lateral overlap of p orbitals in conjugated systems. These orbitals are crucial for understanding the electronic properties of cyclic and planar molecules, and they determine optical, chemical, and aromatic characteristics in unsaturated compounds.

Relative Energy Level Diagram

A Relative Energy Level Diagram is a schematic representation of the energies associated with molecular orbitals in a molecule. This diagram is used to illustrate the ordering, spacing, and occupancy of orbitals, informing predictions about molecular stability and reactivity in various electronic states.

Electron Configuration in Conjugated Systems

Electron Configuration in Conjugated Systems refers to the manner in which electrons fill the available molecular orbitals in systems with delocalized electrons. This concept is essential for determining the overall electron count in different species (neutral, cation, radical, anion) and predicting changes in their electronic and magnetic properties.

Aromaticity and Hückel's Rule

Aromaticity is a property of cyclic, planar molecules with a conjugated ? electron system that leads to enhanced stability. Hückel's Rule, which states that a molecule is aromatic if it has 4n+2 ? electrons (where n is a nonnegative integer), provides a quantitative criterion for aromatic stability. This concept explains the unique stabilization observed in molecules like the cycloheptatrienyl cation.

Transcript

00:01 Solving problem 45 of chapter 15.

00:06 So we need to draw the structure of the cyclo -epta -triening system.

00:11 And then we draw the corresponding cation, radical and anion.

00:16 We need to draw the seven orbitals and show which one is filled in each of them and explain the aromaticity of the cadion.

00:29 So let's start drawing the three structures.

00:31 We have a cyclo -epta triennial, that means we have seven carbon atom, so one, two, three, four, five, six and seven.

00:46 Three anil, so we have three double bonds.

00:51 And let's start in here from the catayune.

00:55 And then we have one, two, three, four, five, six and seven.

01:03 One, two, and three, let's draw the radical, and then let's do the anion, two, three, four, five, six and seven, and this is the anion.

01:25 So the problem is telling us there are seven orbitals, so we have one, two, three, bond, anti -bond, one, two, three, four, five, six and seven, one, two, three, four, five, six and seven.

01:47 One, two, three, four, five, six and seven.

01:52 Okay, so now let's count the electrons in the catalan that are contributing to the pi system.

02:02 We have two, four and six.

02:06 So we start from the lowest orbital in energy, two, three, four, five, and six.

02:20 Let's move to the radical...

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