Week 4: More Manganese

This week I continued to study manganese ligands. After a lot of research, I had the opportunity to try a different way of making manganese oxalate than the procedure we used last week. The new method produced a dark pink solution of manganese oxalate, and it was stable for about 30 minutes. I enjoyed the experience of designing and carrying out my own experiment, along with a lot of help from my mentor.  When some leucoberbolin blue (LBB) was added to the manganese oxalate solution, it slowly formed a dark blue color, which was exciting because we have been trying to get good kinetic reaction measurements of the ligands without much success, since the reactions we measured last week were all so fast. Next week, however, we are hoping to test the new manganese oxalate solution with LBB and get some useful kinetic data on it. In order to prepare for that, on Friday I made up a new LBB with potassium permanganate calibration curve. We plan to use the trendline from the calibration curve to calculate the rate of the reaction of manganese oxalate with LBB. The trendline is in the form y = mx + b, where y is the absorbance from the LBB/potassium permanganate solution in OD, m is the slope of the line, x is the concentration of LBB oxidized by manganese, and b is the y intercept. The absorbance data from a given manganese solution – in this case manganese oxalate – can be converted to concentration, and the change in concentration can be plotted versus time to give a reaction rate.