Dr. Seth Elsheimer
The 13C chemical shift concentration dependence of phenol, anisole, thiophenol, and thioanisole in CDCl3 was acquired and analyzed over various concentration ranges and reported with the intention of observing the effect of hydrogen bonding on the electron density around aromatic nuclei. Of the para carbon chemical shift concentration dependences observed, phenol exhibited the most significant concentration dependence. Attempts were made to determine the functions describing concentration dependence of the 13C chemical shifts observed. Notably, CDCl3 was found to exhibit relatively nonlinear concentration dependence in the same range as the compounds observed, suggesting that trace impurity and solvent peaks are not reliable references for the identification of absolute chemical shifts at an accuracy greater than ± 0.15 ppm for the concentration range 1.0 – 7.0 molal.
Lowers, Braxton and Reed, Adam
"13C Chemical Shift Concentration Dependence of Phenol, Anisole, and Their Sulfur Analogs as a Probe into Anomalous Reactivity in Electrophilic Aromatic Substitution Reactions,"
The Pegasus Review: UCF Undergraduate Research Journal: Vol. 13:
2, Article 7.
Available at: https://stars.library.ucf.edu/urj/vol13/iss2/7