Modeling the Solvation Effects of Dopamine and its Precursor Tyrosine Using Gaussian 03W

Abstract

Dopamine is a neurotransmitter, with the amino acid precursor, tyrosine. Both molecules were modeled using Gaussian 03W/GaussView03 to observe their solvation effects. An initial carbon tetrahedral test was run on the literature-found basis set values, B3LYP/6-311++G** and B3LYP/6-31G*, to decide which was most optimal for larger-scale use. The B3LYP/6-31G* basis set was found to be the most optimal producing the lower energy value of -40.51975 A.U. as compared to the B3LYP/6-311++G** basis set that produced an energy value of -40.52004 A.U . Then, the amino acid tyrosine was modeled and calculated for optimization and frequency, single-point energy and solvation in water, which resulted in values of -3.510 A.U, -554.591 A.U., -554.556 A.U., and -554.582 A.U respectively. The dopamine molecule was modeled and calculated for optimization and frequency, single-point energy, and solvation in water, which resulted in -4.331 A.U., -516.352 A.U, -516.352 A.U. and an inconclusive result, respectively. When compared to each other, these values are lower in dopamine as compared to tyrosine. This may be because the structure of dopamine is more evenly divisible with two of the same functional groups and that it is aromatic. The solvation of dopamine could not be compared to prior studies conducted on the solvation of acetylcholine because there was no obtained result for the solvation of dopamine in water.