Miscellaneous Problems

Cycloaddition (a) given below gives a mixture of isomeric A and B. But C gives only A. Give the mechanism for these reactions. 

Predict the stereochemistry of each of following reactions assuming reaction 

Stable carbonium ion solution can be prepared in fluorosulphonic acid. Stable carbonium ion in FSO3H when subjected to photolysis at low temperature (T -60°C) following 13 )0 of transformation takes place. 

Products (B) and (C) have been found to be stable inFSOjH at-76°C, they do not undergo rearrangement. Suggest mechanism of above transformation. 

View the following reaction sequence, classify each step and determine the reaction condition for it. 

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In the following three sections we shall discuss four applications of quantum mechanics to miscellaneous problems, selected from the very large number of applications which have been made. These are the van der Waals attraction between molecules (Sec. 47), the symmetry properties of molecular wave functions (Sec. 48), statistical quantum mechanics, including the theory of the dielectric constant of a diatomic dipole gas (Sec. 49), and the energy of activation of chemical reactions (Sec. 50). With reluctance we omit mention of many other important applications, such as to the theories of the radioactive decomposition of nuclei, the structure of metals, the diffraction of electrons by gas molecules and crystals, electrode reactions in electrolysis, and heterogeneous catalysis. 

A catalyst system159 consisting of a mixture of boron trifluoride, acetic acid and pyridine gives rapid and reproducible total hydroxyl analysis (silanol plus water) in a variety of silicone materials. This method avoids many of the interferences, empirical calibration and miscellaneous problems such as poor solubility, incomplete reaction and interfering siloxane cleavage associated with many earlier methods. Results obtained by this procedure compare well with results obtained by the lithium aluminium hydride procedure160. 

In assessing the significance of theoretical and experimental results on stilbene probes presented in this chapter, we may conclude that these molecules possess a potential for solving miscellaneous problems in chemistry, biochemistry, and biophysics on molecular level. Owning to high sensitivity, simpUdty, availability of fluorescence techniques, these stilbene probe methods can be widely employed. 

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