Is science sometimes in danger of getting tunnel vision? Recently published ebook author, Ian Miller, looks at other possible theories arising from data that we think we understand. Can looking problems in a different light give scientists a different perspective?

My History Of Cyclopropane Conjugation

Polly-Anna Ashford posted a comment about PhD supervisors, and instead of commenting, I thought I would post my experience here, mainly because it was my PhD that got me into the alternative interpretations game.

My PhD started like this. I was given a nice looking project, but just as I was about to start, there it was published in the latest JACS. (Better then than 2 years later!) My supervisor gave me two possible new projects and went on holiday. Project 1 involved measuring the rate of some reactions, however, a quick search of the literature gave the answer: zero! Project 2 verged on the suicidal - heating about 3 kg of material with nearly a kg of diazo compound to get a few grams of starting material from several kg of carcinogenic tar. So, head of department suggested I find my own project, which I did. I would enter the emerging controversy on whether cyclopropane was an electron conjugating entity. It seemed a good project but for some synthetic difficulties, not helped by the fact that one key Tet. Lett. kindly omitted the fact that a key reaction had to be done at minus 80 degrees!  (Silly me for not picking that.) So I had to make everything the long way, and by the time I was getting to the meat of the project, supervisor disappeared off for a 1 yr sabbatical. In the end, it dragged out to nearer 18 months by which time I had virtually had to work it out myself.

Four things then happened in fairly quick succession. Supervisor reappeared and came up with a genuinely constructive idea, then disappeared again, searching for a better paying job in North America. The scientific community became firmly convinced that cyclopropane did conjugate because (a) it stabilized adjacent positive charge, and (b) use of the Hammett equation showed that the constant rho, which the degree of transmissability (sorry about that word!) was 30% higher than (CH2-CH2). However, in my work, the Hammett sigma "constants", which actually vary depending on whether there is conjugation (!), showed no conjugation. I then realized the value of rho was exactly as expected with no conjugation but with the additional path, and more to the point, I saw why cyclopropane should stabilize adjacent positive charge without conjugating. The reason lies in the nature of the potential energy in electromagnetic interactions. (In my ebook, I give the example, throw a stone in the air. At the top, its kinetic energy is converted to potential energy, but where is that energy?) In short, I decided that if you considered cyclopropane to be a strained system, before you start postulating strange effects, your reference point should be in accord with Maxwell's electromagnetic theory. The problem then, of course, is that Maxwell's eelctromagnetic theory is not included in most chemistry courses, which is odd since chemistry depends on electromagnetic interactions. The fourth event was, of course, I had to write up my thesis, more or less on my own. What should have happened was that my supervisor should have sat me down in front of a physicist and got my analysis sorted out, but recall my supervisor was on another continent. So, Polly-Anna, are things for you really that bad?

Post-script. Supervisor, who had no intention of putting his neck out, refused to publish the data resulting from his "good idea" because the results contradicted emerging consensus, and the emerging "proof" of conjugation through MO theory, including some work published by the emerging John Pople. These versions of MO theory were exactly the same as predicted the exceptional stability of polywater, so forgive me if I am unimpressed by that "proof". I published a small series of papers,  but I botched the first one by assuming the reader would follow the essence of Maxwell's theory, and I got carried away by the fact that I had an approximation that got an analytical solution to an otherwise insoluble set of partial differential equations. The highlight arose for me when I realized that the n -> pi star transitions of a carbonyl group would generate a charge transfer towards the cyclopropane ring, and while conjugation requires a bathochromic shift, my theory permitted me to calculate the hypsochromic shift to within 1 nm of observation. Triumph? Well, no. One review dismissed these hypsochromic shifts as "unimportant". The authoratative review came out and decided that cyclopropane conjugates, and this is found in most text books. It completely ignored my work, and it completely ignored all the data I had found to support my theory. I later wrote a logic analysis type of review in which I listed over 60 different types of observations that are not in accord with the conjugative theory. The journal that started this review rejected it because there were too many mathematics! Other journals refused to accept logic analyses.

So, Polly-Anna, and others who are a little less happy at the bench, be grateful you do not make too much of a discovery. It is not the good thing to do that I imagined when I made that one. If you go against consensus, too many people have too much to lose, so if you do not win quickly, you lose badly, and you would be surprised how many people dismiss you out of hand. On the other hand, join the flow and anything is forgivable. You may recall John Pople won a Nobel Prize. His assertions on the stability of polywater were put aside for that!
Posted by Ian Miller on Jan 14, 2012 11:06 PM Europe/London

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