Computational Chemistry at GVSU

Off-Week Exercise: Building b-carotene

In this exercise we will build a somewhat complicated molecule, b-carotene. b-Carotene is a member of the carotenoid family, which is a group of light-absorbing molecules found in plants. The carotenoids are responsible for the beautiful fall colors we will soon see out our windows, which is one reason I have chosen this molecule. These molecules absorb wavelengths of light that chlorophyll doesn’t absorb particularly well, thus broadening the spectrum of light from which a plant can extract energy. The other reason I chose this molecule is more pragmatic; we will use this structure later in the semester, when we perform calculations on conjugated dyes.

1. Find the 2-D structure of b-carotene (feel free to use the internet for this). Record it below:

 

 

 

 

 

 

 

 

 

 

 

2. Build b-carotene using Cerius2, making sure to build the correct cis-trans stereochemistry. Are there any chiral centers to be concerned with?

 

3. Save your b-carotene model, under "File" and then "Save Model". Choose a filename that you will remember over a month from now, and add ".msi" to the end.

 

4. Have the instructor check your model, and sign approval below:

b-Carotene is built correctly, signed_________________________________________