I was feeling remarkably happy when my thesis was written, because I felt I had made an important advance, and then, disaster! Maerker and Roberts published a paper (J.A.C.S. 1966, 88, 1742-1759) that asserted that the cyclopropyl ring also stabilized adjacent negative charge. If this were correct, the cyclopropane ring did conjugate with adjacent charge, and my polarization explanation, and my PhD thesis, were just plain wrong. The reason is, of course, that a polarization field will stabilize one charge, but must destabilize the other, because the force between like charge is repulsive. My first response was deep despair; my second was, perhaps I had better read this paper carefully.
 
There are three major complications. The first is that if the lack of stability is indicated through rearrangement, that only means something else is more stable. Thus a Grignard reagent made from cyclopropylmethyl chloride leads to a ring-opened rearranged "carbanion". As it happens, the cation made from cyclopropylmethyl chloride, or cyclopropylmethyl alcohol, or a tosylate, is also unstable and promptly rearranges. (This is the famous bicyclobutonium "non-classical" carbenium ion.) Rearrangements of the carbenium ion are inhibited by bulky substituents, but the stabilizing effect of the cyclopropyl ring is easily shown by considering the rates of formation of the ion, or the energy of the species by mass spectrometry. However, at the time neither of these techniques were available for the anion. The second is solvation. Carbanions tend to be generated in solvents such as ether or petrol, which almost forces ion pairing, whereas the carbenium ions tend to be made in acids more acidic than concentrated sulphuric acid, and hence have very high dielectric constants and strong solvating properties. Thus the cyclopropycarbinyl carbenium ion made in solution is never stabilized to anywhere near the extent as is found by mass spectrometry. The third is that the polarization field is not a simple field. Four orbitals move towards a substituent, but at the corner of the cyclopropane ring, there is weak positive polarization field, due to the movement of the three orbitals about that atom, which, being very close, over-ride the stronger effect of the more distant movement. Further, while the cyclopropyl anion receives some localized stabilization together with the expected destabilization, the associated cation in the ion pair is strongly stabilized, and overall, the "anion" appears to be slightly stabilized. This effect is most strongly seen in calcium carbide, which, of course cannot be stabilized by conjugation without violating the Exclusion Principle. Further, according to the polarization interpretation, the "bare anion" formed on a carbon atom adjacent to the cyclopropyl ring should be destabilized, but by less than half as much as the cation is stabilized (because the charge is more distant, and by applying the virial theorem). In solution, solvation becomes an issue, as does the location of the cation.
 
So what was the evidence Roberts found relating to the conjugative stabilization of the anion? Some of the evidence, in my opinion, falsified the conjugative explanation because the anion refused to form when it should have. Such failures included: treating with butyl lithium (which meant that the protons were less acidic than those of butane), refluxing for 46 hr with phenylpotassium in heptane, treating with pentylpotassium (which reacts smoothly with ethylbenzene), stirring at 80^o in heptane with potassium and sodium monoxide. My theory might be still alive!
 
However, evidence for conjugation was claimed when the phenylmethylcyclopropylcarbinyl anion formed with potassium as the counterion, but it rearranged to the corresponding allylcarbinyl anion with any tendency towards covalent character. Roberts argued (almost certainly correctly) that when something like lithium was the counterion, the lithium would get close to the anionic centre and partial covalent binding would occur. Potassium was big enough that the bulky substituents forced it away. However, it was here that we differed in our interpretation. Roberts claimed that the extra stability with potassium was due to the fact that the "pure anion" was formed, and the cyclopropyl ring provided conjugative stabilization. My interpretation was, the potassium formed the "pure anion", which permitted delocalization, which in turn permitted the anionic charge to be delocalized by the benzene ring, out of range of the cyclopropane ring. Any attempt at localizing the negative charge on the carbinyl carbon led to repulsive interactions from the cyclopropane ring, and hence rearrangement.
 
There were two problems with that explanation. The first is, is it convincing? You, the reader, can judge. The second was, there was no way to publish it. The problem with a scientific paper was, once something was asserted, that explanation stood. Falsification with independent evidence was required, not a simple assertion. Nevertheless there is another lesson here. Just because somebody asserts that something has happened, that does not make it so. Read the evidence carefully!

I apologize for the font-size in the last post. This was done from my laptop while on vacation, and for some reason, with different software, I got the wrong outcome. Sorry.

Let me now revisit my first paper for the last time. This paper was cursed by the referees: they accepted it without comment! Nevertheless, it is a paper that is an example of how not to publish a new concept, and it might be of help to young chemists to consider these errors, so as not to make them themselves. For those interested in the paper itself, see Tetrahedron 25 : 1349-1360 (1969).

The first error was that I put both the strain formulae and the means of explaining the dipole moments into one paper. I should have submitted two. The reason is, with two points to make that may be of value to different audiences, one of the points will be embedded in the paper, and the audience for that paper will never find it. I did not wish to be accused of not having enough material, or of unnecessarily trying to increase my publication count. That is silly thinking. There were a number of other papers out there relatively short on substance, and in any case, if both papers were submitted at the same time, let the referees/editor suggest merger.

The second error was that I did not state clearly, separate from the rest, what I had found. The basic point was that the changes of dipole moments were caused by enhanced electron density over normal alkanes, and the "compression" of the electron cloud present was proportional to the work done "compressing" the electron cloud. I relied on the fact that someone would follow what I had done by reading the paper, and by drawing the obvious conclusion from the table, but that is not good enough. If you want to persuade an audience, say it in the abstract, start the introduction with why you have to say it, say it in detail in the text, show it in the table, and say it again in the summary.

The title, "Ring strain and the negative pole" was, I thought, clever, because it related ring strain to the polarization field in the shortest space. Advice to young scientists: if you think of a clever title, try it out on some other scientists and see what they think. It may merely make them shake their heads!

Perhaps the biggest mistake was that I failed to explain fully what I was doing. The last thing I wanted to do was irritate "the real chemists" by labouring the obvious. What I did not realize was that what was obvious to me was not necessarily obvious to anyone else! I had taught myself physics, and I had bought the cheapest suitable books, which happened to be produced by Mir publications in Moscow. What I had not realized was that what was considered to be interesting additional information in Moscow was simply not present in the more expensive western textbooks. (I do not care what anybody says; for me, Landau and Lifshitz’ Mechanics is still by far the best book for learning about Lagrangian mechanics.) Accordingly, I assumed any physics in a textbook I could follow was well known, and I did not want to be accused of padding the paper with trivia. I thought that taking a divergence of a polarization field to get a pseudocharge (the pole) would be obvious. Obviously I should have said exactly what I was doing, but I was young and unguided. Worse, I did not want it rejected for being too long, which, of course, was all the more reason to submit two papers. I suppose also I was rather pleased with myself for finding a way to get an analytical solution that avoided insoluble partial differential equations.

So what happened? Apparently some chemists thought I was generating charge, which violates a variety of conservation laws. Of course I was not: I was merely trying to give an easier way of putting a numerical cause to the changes in the electric field that must arise when energy is stored in it. Since my undergraduate training in chemistry had given me no enlightenment to Maxwell’s electromagnetic theory, I should have realized it was wrong to assume everyone else would understand.
 
So, I hope young chemists might find something helpful from this. If nothing else, try to get someone else to read your paper and tell you what you said. That way, you will know whether it is comprehensible.

As outlined in a previous post, my PhD  results meant that I had to find a way to account for the strange properties of the cyclopropane ring without invoking conjugation. What I came up with was to account for them through a polarization field that was generated through the work done moving orbitals towards the centre of the strained ring. Thanks to the dimensional equivalence of a polarization field and a displacement field, and thanks to Maxwell’s electromagnetic theory, I could represent the movement of charge (the real cause of  the polarization field) in terms of the addition of a pseudocharge to orbitals that had not moved (equivalent to a change of displacement field). I could do that similarly with increased charge density, and the reason for doing this was that it permitted a known solution to the partial differential equations, with only one constant required to be set. I used the electric moment of cyclopropyl chloride to set that constant, and hence the pseudocharge. Now, the question was, would the same pseudocharge properly account for the stabilization of adjacent positive charge?

 

The cyclopropylcarbinyl cation was known to be stabilized compared with corresponding alkyl cations through studies of solvolysis of tosylates, etc, but these studies were of lesser value because there was the problem of solvation energies. There was also an issue that the cyclopropylcarbinyl cation is also unstable and promptly rearranges. (This is the famous bicyclobutonium "non-classical" carbenium ion.) Substitution can stabilize it, but that adds complications. Then, luck! Well, sort of. The stability of the cyclopropylcarbinyl cation was published in a PhD thesis, and reported in some books on mass spectrometry, but for some reason it never seemed to have made its way into a paper. Someone else was having trouble getting supervisors to publish! 

 

However, I had a reported value for the gas phase cation and I could use my pseudocharge to calculate the energy of the interaction of such a polarization field with the cationic centre. Obviously, this would be a fairly crude calculation, and there would be a number of minor effects overlooked, but I needed to know whether I was even in the right ball park. To my surprise, the agreement with observation was very good.

 

Of course, there was an easier way of doing this calculation. If the strain energy arose through charge in orbitals moving closer together and thus raising repulsive energies, and if four of the six moved closer to the substituent, then the cationic charge would neutralize the repulsive energy on these, hence the maximum energy of interaction with adjacent charge would be 2/3 the strain energy, plus any additional standard stabilizations that would occur in any carbenium ion. However, as far as I was concerned, the triumph was that the same value of my pseudocharge gave correct values for a completely different type of observation for which there was no obvious relationship other than the proposed theory. Being young and inexperienced in the ways of the world, I  thought I was making headway.

January was mainly a good month for my theory of planetary formation because two papers were published that strongly supported two of the proposals in my ebook that are not generally accepted. There was a third paper that is also highly relevant.
 
The first relates to where the volatiles of the rocky planets came from. There are two propositions that are usually debated: the volatiles were delivered by comets, or by chondrites. A review written by Halliday (Geochim. Cosmochim. Acta, 105, 146-171) showed the ratios of H/C/N are inconsistent with any ratio of these. All my review could do was to say that only minor miracles would permit some combination, but now even minor miracles are ruled out. My argument is that the volatiles were accreted chemically along with everything else, and the different ratios of volatiles on these planets arose because the materials from which they were made originated in different temperature zones.
 
The second paper was even more important, although I am not quite sure the authors themselves appreciated the full impact of what they discovered. One problem for planetary formation is, when the planets start forming, they form in a disk full of gas, so the question is, why do not the planets head towards the star? They are, after all, orbiting in the equivalent of a stellar "atmosphere". There are a number of papers written on this, but they generally lead to all planets ending up close to the star. What I proposed was that because the gas is falling towards the star and the azimuthal velocity is less than the Keplerian velocity at that distance, a pressure wave builds up in front of the body. That would normally cause the orbit to decay, but because there are solids in the gas, and because the gas has definite radial velocity, the planet starts spinning up, as if rolling around its orbit as material with an inwards radial velocity is accreted on the leading face. All the giants do this, although Uranus provides a problem. The body then drags gas down across its leading face, and when it becomes more gravitationally significant, it holds onto some and drags it around to its starwards side, where it strikes gas coming the other way (in its sub-Keplerian orbit). Two gas streams flowing in opposite directions cancel their velocities, in which case the gas will stream towards the star, gradually merging into the more general flow. The original angular momentum lost must be conserved, and only the orbiting body can take it up. By gaining angular momentum, it tends to move away from the star, thus offsetting the expected orbit decay.
 
The paper that excited me was due to Casassus et al. (Nature 493: 191-194). What they did was to observe the star HD 142457, which is still in the late accretionary stage, and they found two filaments of gas streaming inwards with a radial velocity greater that the azimuthal velocity by approximately 10% or greater, and further, the flows in these filaments were approximately equal to the rate of stellar accretion. It gives a surprisingly pleasant feeling to find what you predicted, as much out of desperation as anything, actually turns up.
 
There have been a variety of estimates of how much gas is present in the late stage of stellar accretion. This is important because our planetary system requires about 1% of stellar mass, and previous estimates varied by about two orders of magnitude, with only the higher end having sufficient material. In my ebook, I assumed an average, hence I required initial planetary accretion to commence earlier.  The third paper (Bergin et al. Nature 493: 644-646) provides a new means of estimating the mass in the disk by using the emissions from hydrogen deuteride, and from observations on TW Hydrae, which has a disk between 3-10 My old, the disk contains 5% of the stellar mass, which the authors state is easily enough to form planets. As it happens, this system has been reported to have a planet of about 10 Jupiter masses rather close to the star, the star continues to accrete disk gas (For TW Hydrae, approximately 1% of gas per My), and after a period, the great bulk of this disk is blown away by a stellar outburst. Further, as Casassus showed, planetary accretion must be highly inefficient if planets throw gas inwards instead of accreting it. Accordingly, I think that the odds favour my concept that planetary formation must have started earlier. Either way, though, this evidence strongly suggests that planets are more likely to form around stars than not, so the probability that we are alone in the Universe has probably just got a lot lower.