The two-datapoint plot

29 August 2010 - Statistics

Wieland rearrangement DiLAbio.jpgIt should be a thing of the past , the two-data point plot, at present occasionally observed in classroom projects or with lazy coworkers but surely not in serious research?. Yet DiLabio at el. accomplished such a feat in Angewandte Chemie (DOI). The article in question is about the Wieland radical Ph3CO. that rearranges to the Ph2C.OPh radical (see: 1,2-rearrangement for details). The two data points in the plot on the left are two experimental first-order reaction rate measurements at two different temperatures allowing the calculation of the activation energy (5.6 kcal/mol) for the rearrangement via the Arrhenius equation. The reader is spared the straight line connecting the two points but the obvious course of action would be to analyse the reaction rates at more temperatures increasing the accuracy of the end result. If there were any practical limitations to the temperature window the authors do not share it with the reader. The second set of data points - this time with an accompanying line - is based on DFT computational chemistry which is odd as well. The actual value computed is the activation energy itself (6,2 kcal/mole , energy radical vs energy spiro transition state) so instead of just 5 data points you can have as many as you like and that with a certified correlation coefficient of 1. No need for the datapoints then?