14 Jun Riley Embrey – University of Houston Week Two

I made it through the second week of being at the University of Houston, and it is safe to say that we are starting to get into the nitty gritty of my project. Last week I covered all of the surface-level topics covered in macrocyclic and supramolecular chemistry, but this week we zoomed in into more specialized areas. This week I got to participate in NMR titrations, analyze the data through new software, and bond with the grad students I share the space with!

About my project:

Banana in the lab?!

On Monday, I participated in the NMR titration of two macrocycles, slowly adding a new anion to the solution. While I could not place the NMR tubes directly into the NMR (Nuclear Magnetic Resonance) machine, I got to watch as well as add the guest solution into the host samples being tested. Through this, I got experience in measuring exact amounts of a solution, and calculating the amount of guests (anion) added.

After collecting all of the data, I further explored how to understand NMR readings, specifically what it meant when a proton shifted on the ppm spectrum.

NMR Machinery

To clarify, an NMR spectrum shows on the x-axis how deshielded or shielded a proton is on a molecule. This can help you determine the structure and composition of the molecule. Further, the y axis shows signal intensity. However, the number of protons is determined from the integration of the peak, not the height. The integration number is the total area under these signals, which then give you the ratio of protons on the spectrum. 

When titrated with an anion, this causes the electron distribution of the host to change, causing certain protons to be more deshielded (Or more visible on the spectrum). As more guest solution is added, you can determine which protons are closest to the anion depending which one shifts downfield the most. Using software and the NMR spectrums now obtained, we obtained the binding constant of these macrocycles with this specific anion. Moving into next week, I will start learning how to use a new software to resemble these macrocycles and other molecules. This will give me new insight in how these molecules are structured, and hopefully help me understand more thoroughly on how these cyclic components work!

Fun Fri-yay: June 12th

The NMR machine is off-limits for minors, I will not have direct access to it during my intern-

-ship. Because of this, some of the grad students in my lab thought to have a sort of fun day and do experiments around the lab. Many of them were experiments you would see at a science fair, but I still learned a lot about the different machinery in the lab as well as having fun in the work environment.

Outside of the lab: 

On our off time, all of the girls (Brylea, Cricket, me, Faye, Marley, Haebin, Maria) kept exploring the campus and finding new places to eat, have fun, and hang around. Today, on Sunday, most of the Welch group took the Metro into downtown Houston and saw either Backrooms or Scary Movie at the AMC Theatre. Afterwards, we went to a place called “Post” where a giant World Cup watch party was happening in a food court. The food in Houston has been delicious everywhere I’ve gone, including the dining hall! I look forward to next week, and I will see you in my next post!

“Post” in downtown Houston!