Deceptive simplicity

These signals were delected as a mnlliplel at 6.20 6.50 ppm. h These signals show deceptive simplicity. 

MORE ABOUT THE ABX SYSTEM DECEPTIVE SIMPLICITY AND VIRTUAL COUPLING... 

As the ratio of A 8v (the difference in chemical shift between two coupled nuclei) to J decreases, the relative intensities of the lines in a multiplet deviate further from first-order (e.g., Pascal triangle) ratios. Inner lines (those facing the coupled multiplet) increase in intensity, while outer lines lose intensity. This slanting of the multiplets is one type of second-order effect. At very small values of A Sv/J, not only may extra lines appear in the multiplets but also apparent line positions and spacings may not equate with true chemical shifts and coupling constants (e.g., deceptive simplicity and virtual coupling). 

Second-order spectra are characterized by peak spacings that do not correspond to coupling constants, by nonbinomial intensities, by chemical shifts that are not at the midpoints of resonance multiplets, and by multiplicities that do not follow the n + 1 rules. (See Figures 4-1, 4-2, and 4-3.) Even when the spectrum has the appearance of being first order, it may not be. Lines can coincide in such a way that the spectrum assumes a simpler appearance than seems consistent with the actual spectral parameters (a situation called deceptive simplicity). For example, in the ABX spectrum, the X nucleus is coupled to two nuclei (A and B) that are themselves closely coupled. When is extremely small, the A and B... 

An X-ray crystal structure of compound [268a] has been reported independently, (146) and the, 9F shifts and splittings given in this paper agree well with those in Table XV. The triplet spacing in the CF signal, however, was incorrectly attributed to accidental equivalence of the cis-and trans-P-CF couplings, rather than to deceptive simplicity in the AA XX system ... 

Has appropriate quantum mechanical analysis been performed Is there deceptive simplicity in spectra Are line assignments correct ... 

The apparent (even if rather deceptive) simplicity of these structures gives the feeling that simple algorithms requiring negligible computation, such as the Gordon-Davison method for unbranched cafa-condensed benzenoids or its reformulated... 

A survey of the current literature reveals that despite the molecule s deceptive simplicity, the description of the nature of the lower-lying electronic states which contribute to the vacuum u.-v. absorption remains controversial. Particular difficulties arise over the number and identity of the excited states which are associated with the broad-band continua. ... 

Deceptive Simplicity. Sometimes the combination of parameters is such that a deceptively simple spectrum results. Consider the spectrum of furan. 

The interest of organic chemists in the interpretation of acid catalyzed reactions dates back to the very early measurements of reaction rates(l). The most widely known and applied theory is the one proposed more than 40 years ago by Zucker and Hammett(2) and later reviewed by Paul and Long(3). According to this theory we could reveal whether the reaction mechanism is of the A-1 or A-2 type by checking whether the increase in logarithm of the experimental reaction rate depends on the first power of H or log c +, respectively. Probably because of its deceptive simplicity, this criterium has found very wide applications. Although Hammett himself has pointed out(4) on the shortcomings of this criterium there are few researchers who still apply the Zucker-Hammett hypothesis. Let s quickly discuss the reasons why this criterium is not valid. The rate expression for the A-1 mechanism, depicted in equation 1 and 2, is reported in equation 3... 

There are no really complex s)mthetic procedures yet. However, even very simple steps taken in sequence can lead to difficulty. This area will rapidly proliferate and become more difficult, so do not be lulled by the deceptive simplicity of the... 

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