Acetyl Ferrocene Lab Report

Discussion:
The melting point of the synthesized acetyl ferrocene was found to be 162-163˚C, 77 ˚C higher than the 85-86˚C literature value melting point range for acetyl ferrocene. Exponential difference in melting point value shoes that acetyl ferrocene was not produced in the reaction, and instead the reaction re-produced ferrocene as a product. The 162-163˚C melting point range is evidence of this, as it correlates far more closely with the 173˚C1 melting point average and/or 172-174˚C8 melting point range of ferrocene. The re-development of ferrocene can most likely be attributed to excess H3PO4 used at the beginning of the reaction when forming the acylium ion. However, it is about 10˚C temperature variation below the desired temperature

The highest Rf can be found in the initial ferrocene starting material, which was expected. This is due to the fact that Ferrocene was able to best interact with the predominantly non-polar toluene: ethanol (30:1) solvent and be carried along the silica gel when the TLC was performed. As expected, the lowest Rf was found in the purified acetyl ferrocene, however this is not because of the polar properties of a successfully synthesized acetyl ferrocene product Acetyl ferrocene was not produced. It was the polar properties of water contaminating the final re-produced ferrocene product that lead to lower Rf

The represented the exact peak assignments for acetyl ferrocene, which contains 4 strong singlet peaks at between 2.3-2.4ppm, 4.25-4.35ppm, 4.45-4.6ppm, and 4.7-5.0ppm. The medium singlet peak located between 2.3-2.4ppm at 2.39ppm represents the proton environment of the methyl group protons branching off the acyl group of acetyl ferrocene (3H). It is located furthest downfield as it does not suffer from electron withdrawing effects provided by resonance. It falls between the range of standard shifts for protons of ketone acyl groups, which is between 2-4ppm. The large singlet between 4.19-4.35ppm at 4.20ppm represents the proton environment of the five aromatic protons present along the lower pentene ring of acetyl ferrocene (5H). This finding deviated from the norm when interpreting aromatic 1H NMR spectra, as they typically are found between 6.0-9.2ppm. This deviation can likely be attribute to the aromatic ring not being a benzylic aromatic compound, with fewer resonance structures due to having fewer pi bonds and carbons to delocalize electrons throughout the ring. The singlet peak between 4.45-4.6ppm at 4.50ppm represents the proton environment of the beta hydrogen atoms (located two carbons from) the acyl group on the top ring of acetyl ferrocene (2H). They are located slightly further upfield than the two alpha protons (present in the environment one carbon away), which are between 4.7-5.0ppm (2H) at