Unexpected results

In this series of results, we encounter a somewhat unexpected result, namely, when the circle surrounds two conical intersections the value of the line integral is zero. This does not contradict any statements made regarding the general theory (which asserts that in such a case the value of the line integral is either a multiple of 2tu or zero) but it is still somewhat unexpected, because it implies that the two conical intersections behave like vectors and that they arrange themselves in such a way as to reduce the effect of the non-adiabatic coupling terms. This result has important consequences regarding the cases where a pair of electronic states are coupled by more than one conical intersection. 

The vastly increased acidity of superacidic systems resulted in the significant new field of superacid chemistry. I began to ask myself whether a similar but more general approach could be used to produce electrophiles of greatly enhanced electron deficiency and thus reactivity. Over the years, there were a number of unexpected results in my own research work, as well as some previously unexplained observations buried in the literature, that seemed worth pursuing. 

It would clearly be of interest to discover how far the nonane method can be used with adsorbates other than nitrogen. A study along these lines has been carried out by Tayyab, but a discussion of his rather unexpected results is best deferred until the role of fine constrictions has been considered (p. 228). Meanwhile it may be noted that the applicability of the technique seems to be limited to adsorptives such as nitrogen or argon which have negligible solubility in solid or supercooled liquid n-nonane. 

In the 6-chloro-A " series diazomethane addition and pyrazoline cleavage require more strenuous conditions. " An unexpected result is observed with the 4-chloro-A system (15) which adds two equivalents of diazomethane to give the 4-chloro-la,2a 6, 7 -dimethylene compound (16) in 16% yield after cleavage of the labile crude bispyrazoline with a catalytic amount of perchloric acid. The assignment of the -configuration to the 6,7-methylene group is based on the shift of the 19-H NMR resonance to higher field. 

Raghavachari offers several possible explanations for this unexpected result ... 

Since we need to find both triplet and singlet excited states, we ve included the 50-50 option to the CIS keyword. We ve asked for two states of each type, the exact number we require for this well-studied system. When examining new systems, however, it s often a good idea to request slightly more states than you initially want to. allow for degenerate states and other unexpected results. 

Dimethylquinoxaline (303) has been reported to undergo a Diels-Alder reaction with maleic anhydride to give 304, 305 having been postulated to be the reactive form. However, attempted confirmation of this unexpected result has shown that 304 is not the correct structure of the reaction product. " In 1931, other chemical evidence was advanced in support of structure 305,but it would no longer be considered valid. 

Yilmaz comments that several unexpected results have developed from the current horizontal reboiler research studies. 

The final step in an attempted synthesis of laurene, a hydrocarbon isolated from the marine alga Laurencin glandulifera, involved the Wittig reaction shown. The product obtained, however, was not laurene but an isomer. Propose a mechanism to account for these unexpected results. 

Whereas treatment of ( )-29 with camphanic chloride achieves the selective esterification of the hindered C-9 hydroxyl group, the action of acetic anhydride on (+)- 29 results in the equally selective acetylation of the C-10 hydroxyl group It is not clear to what this discrepancy should be attributed, so we will not offer a rationalization here. This unexpected result is, however, most gratifying because TPAP-NMO oxidation27 of the remaining C-9 hydroxyl furnishes keto acetate 6 (88 % overall yield). You will note that the contiguous keto and acetate functions in 6 are both expressed in the natural product. 

The above qualitative conclusions made on the basis of the results of [116, 124-127] correlate with the results of [129,130] in which the calculation is based on composite models with nucleus-shell inclusions. The authors illustrate this with the calculation of a system consisting of a hard nucleus and elastomeric shell in a matrix of intermediate properties, and a system where the nucleus and matrix properties are identical whereas the shell is much more rigid. The method may, however, be also applied to systems with inclusions where the nucleus is enclosed in a multi layer shell. Another, rather unexpected, result follows from [129,130] for a fixed inclusions concentration, the relative modulus of the system decreases with increasing nucleus radius/inclusion radius ratio, that is with decreasing shell thickness. 

The wear characteristics of one plastic as opposed to another vary widely, even among materials that have good natural lubricity. When an application calls for plastic-to-plastic bearings, shafts, gears, or other wear members, the combination of materials must be chosen carefully. Because plastics are not rigid, they do not behave according to the classic laws of friction. It is these deviations that cause some of the unexpected results when plastics are run against metals. 

In some cases, oxidation gives unexpected results (Figure 4.25) with concomitant formation of an Au—C bond. 

In summary we think that, on a superficial basis, a comparison of the effects of different nucleophilic species added covalently at the (3-nitrogen atom of an arenedi-azonium ion yields results that are almost trivial. Of more interest are unexpected results such as those of Exner and Lakomy for the substituent -N = CHC6H5. A possible explanation for the latter results emerged when the twisted structure of the substituent became known. We emphasize, however, that definitive explanations on the basis of Hammett or related substituent constants are not found very frequently. 

Trifluoroacetic acid has been examined as a solvent and chlorination of benzene in this is first-order in aromatic and chlorine, but for benzene a higher activation energy (11.4, determined from data at 25.0 and 45.4 °C) was obtained than for chlorination in carbon tetrachloride this unexpected result was attributed to an increase in desolvation energy of the reactants273. 

Braverman and Reisman111 have found that addition of a carbon tetrachloride solution of bromine to bis-y,y-dimethylallenyl sulfone 20 at room temperature unexpectedly resulted in spontaneous and quantitative fragmentation of the sulfone, with formation of the cyclic a, /3-unsaturated sulfmate (y-sultine) 43a and the tribromo products 44 and 45 (equation 38). Analogously, treatment of the same sulfone with trifluoroacetic acid gives rise to y-sultine 43b. It is interesting to note that from a synthetic point of view it is not even necessary to prepare the diallenyl sulfone 20, since one can use its sulfinate precursor (equation 24) to obtain exactly the same results, under the same conditions. The authors suggested that the fragmentation-cyclization of sulfone 20 may take place by the mechanism depicted in equation 39. 

The cross-section for the reaction, 0 + + N2 -+ NO+ + N, as a function of the ion energy, has a maximum of about 4 X 10 u sq. cm. at 10 e.v. and falls off for higher or lower ion energies. The low energy fall-off of the cross-section explains the persistence of 0 + ions in the ionosphere but is a puzzling and unexpected result. Some very tentative reasons for this fall-off are suggested. 

In the example discussed above, the analysts were dealing with a known sequence and were able to identify the unexpected results easily. If a novel protein was under investigation, these anomalies would not have been obvious and interpretation would undoubtedly have been hindered. A slightly different methodology may therefore be needed, as illustrated in the following example. 

---