The tensor components of the shielding also are being measured via static solid state NMR spectroscopy. Studies of the effect of geometrical distortion on the properties of organic compounds. We have recently studied spiropentyl derivatives in some detail, both with regard to the effects of introducing a bridge which will tend to twist the cyclopropane rings toward each other, and with the cations that are formed in the deamination of spiropentylamine and the solvolysis of spiropentyl derivatives. Other studies are concerned with the effect of fluorine substitution on the stability of small ring cycloalkynes. Studies of solvent effects on reactions .
Solvents often play an important role in determining the rates and products of reactions.
We have developed a reaction field model for studying these effects and have applied it with considerable success to a variety of reactions, including the Menshutkin reaction. Besides the reaction field studies, we also make use of discrete solvent molecules. An example is the reaction of organolithium compounds with organic halides, forming Ate complex intermediates or transition states. We have shown that the stability of the Ate complex can be increased both by complexing the lithium cation, and by the introduction of electronegative groups. Studies of electronically excited states of molecules .