Beginning of Week 4: A Change of Catalyst

Since starting my research, I have found out quite a bit about my original complex.  The cobalt version of my complex doesn’t seem to form when a complexation reaction is performed with the ligand and cobalt precursor.  However, in order to verify that the ligand that I synthesized was, in fact, my desired product, I was advised to perform a metallation with iron and run electrochemical tests.  This would allow me to compare it with a previous person’s research of the same complex.  If the results were similar, then I could confidently say that I had the correct ligand.  So, I performed the metallation, and ran the electrochemical tests, received some interesting results.  The electrochemical technique I used is called cyclic voltammetry.  It is effective in observing if a complex can reduce hydrogen efficiently.  A potential is introduced to a solution containing the catalyst.  In this experiment, the potential is brought from a positive to a negative potential, and then back again.  I am then able to  observe the change in current as the potential is varied.  While performing an acid addition experiment, I anticipated seeing a redox couple (observed by two peaks nearly at the equialent potential, reduction on the potential being brought out negative and the oxidation on being brought back positive) and a catalytic peak.  Where I expected to see one catalytic peak, I saw many peaks.  It is possible that this was observed because the test was carried to a more negative potential than needed.  My professor proposed running my experiment to a less negative potential so that we could see the one reduction needed to ensure accurate results. So, I ran it in a relatively small potential range, and observed on my plot that there was in fact one catalytic peak in this range, and a redox couple.  Since the catalytic peak is at such a cathodic potential, it seems that the complex is extremely efficient.  However, in order to make sure that the peak does, in fact, correspond to a reduction event, I will run photochemical experiments of my complex in order to fully observe it (hopefully) generating hydrogen in a system that should allow it to do so.