I have been puzzling over a couple of issues in the NMR of the molecules I have been making. The NMR person agrees that the observations are both real and that he has never seen such a thing before. This makes me wonder if my molecules are showing me something about NMR that is either an example of a concept we organic folks overlook, and perhaps this concept might have some value beyond being a curiosity. I doubt any reviewer will look closely enough at the spectra to see the issues, so can publish the work. But I still hear the molecules trying to get me to listen to what they have to say beyond moving me closer to my target.
As synthetic and methods development chemists we sometimes see unexpected behaviors from the reactions we run or the molecules we produce. In training future scientists it is important to guide the student toward seeing and thinking about the meaning of these unexpected results. Too often students will just accept whatever happens without asking why they did not see the behavior they should expect based on the lecture material. This make them technicians and not scientists. And, as I have noted in prior posts, technicians run the risk of being replaced by smart robotic systems.
The technician training mode of education places emphasis on running experiments in lab courses and is generally concerned about the yield of the desired product or the desired spectrum only. It is important that we engage the student in the type of inquiry that moves them from technicians to scientists. Participation in research can do this for a student, but being a scientist should not be put on and taken off as we enter and exit the research lab like a lab coat. If your to be a real scientist you are always aware of the unexpected and always ready to address it.
There are faculty members and departments who believe in the concept of inquiry based learning across the curriculum. True inquiry based learning can't be done at a distance or in canned lectures. It takes face-to-face interaction with the real system and guided inquiry to develop a scientists mind. It's expensive which we don't like, but a someone smarter than me once wrote, "If you think education is expensive, try ignorance".
T.S. Hall
Puzzling over NMR is a fun past time.
ReplyDeleteI have a new compound with phosphorous and the long distance coupling is making for fun in assigning all of the 13C peaks.
On the other hand - have you ever looked closely at the alpha methylene hydrogens of tripropylamine? SDBS does not show it, but you can download the pdf of the hnmr from aldrich. It is very unusual, yet I have not seen it discussed or explained.
Often in the past, when I was confident of the structure I shrugged, described the spectrum, and invoking second order effects, admitted I could explain all my NMR observations.
Should have been "could not explain all my observations".
ReplyDeleteAlso, I apologize if the comment is a bit off topic.
You seem to be of an age that you will remember the yellow/orange Morrison and Boyd. Interspersed through that text are current research observations - not all of which can be easily explained.
Too many current organic texts present the material as if there are no more questions. This is consistent with the article in the current JCE questioning whether we should say mechanisms cannot be proven. The authors state that with current technology the statment that a mechanism cannot be proven is no longer true.
I would disagree, the nature of science is that we must always be open to the new experiment that shows the fallacy of our reasoning. Therefore, nothing is sacrosanct, nothing is proven. But, that is a different post.
Anonymous I
ReplyDeleteWe organic chemists can get away with ignoring these anomalies, but should we? What insight do we miss when we ignore these things?
Of course, I never met a puzzle I did not want to solve.
Anonymous II
The yellow/orange edition of the Morrison and Boyd Organic Chem text was out for a dozen years I believe. I was in that generation of chemists who used it when it was by far the most used organic text in the US.
You raise a couple of good issues about teaching and texts which I will shamelessly steal and use in upcoming posts.
Thanks.
T.S. Hall