Molecular Modeling Assignment:

There are two modes:

Building mode (use this mode to make your molecule)

Viewing Mode (use this mode to view the MOs and dipole moment)

Steps:

1. Log-on Process

User Name: jbruin (first initial, last name)

Password: 123456789 (your University ID number)

2. Start PC Spartan Plus program

3. File menu Þ New (go to File menu and select new)

4. Select the Building mode icon

5. Build cyclopentadiene and then minimize the structure by clicking the Minimize Structure Button (in the lower right hand side of the window)

6. Experiment with rotating the molecule. This can be down doing a left button click and drag. [Try the following modifier keys: Shift, Control, Control-Shift, Alt; also, right click drag allows translation of molecule]

7. Save Þ file (save the file)

Use will only be allowed to save your file in your User Account Folder. The directory path to save your file is:

Network Neighborhood:Server1:Student Directories:your User Name

8. Select the Viewing mode icon,

9. The Model Menu allows different viewing options. Try the different modeling views. When finished trying out the different types select the tube model.

10. Setup Menu Þ Calculations

Task: Geometry Optimization

Level: 3-21G*

Verify Charge is 0 and Multiplicity is 1

11. Setup Menu Þ Surfaces

Surface: HOMO

Property: none

Then click the ADD button

12. Setup Þ Submit (this calculation should take between 0.5-4 minutes

option menu Þ monitor (allows you to monitor the progress of this calculation )

13. Once the calculation is finished then:

Display menu Þ Properties Þ Dipole

Note that the dipole moment of cyclopentadiene is given in the diagram.

14. Display menu Þ Surfaces

Select surface=homo

Check the Display Surface box

Under Style, select Transparent.

Try out the different Styles: Dots, Mesh, Solid, Transparent

15. When finished with this molecule close your file:

File menu Þ Close

When asked to save the file, click OK.

16. Start over and calculate the LUMO for Maleic Anhydride.

WORKSHEET

GOAL 1: Calculate the HOMO of cyclopentadiene. Compare and contrast the HOMO diagram of cyclopentadiene given in lecture from the one generated by PS Spartan Plus.

 

 

 

HOMO of cyclopentadiene

(from course reader)

 

 

 

 

 

 

 

Draw the HOMO generated from PC Spartan Plus

GOAL 2: Calculate the LUMO of maleic anhydride. Compare and contrast the LUMO diagram of maleic anhydride given in lecture from the one generated by PC Spartan Plus.

 

LUMO of maleic anhydride

(from course reader)

 

 

 

 

 

 

 

Draw the LUMO generated from PC Spartan Plus

GOAL 3: Time permiting, do the EXO and ENDO alignments of the HOMO of cyclopentadiene and LUMO of maleic anhydride as shown below.

EXO ALIGNMENT

ENDO ALIGNMENT

GOAL 4: Compare and contrast the structure of the ENDO and EXO Diels-Alder cycloadducts

 

 

PC Spartan Plus is a molecular modeling program which approximates the structure and molecular orbitals for a molecule.

action result
left click activates structure (if more than two structures, makes structure the active structure)
left click and drag rotates molecue
right click and drag translates molecule
shift-left click and drag enlarges molecule  
try the modify keys!