Bassindale, Parker, Taylor, Aunerb and Herrschaft measured the x-ray crystal structure of four 1-(halodimethylsilylmethyl)-2-quinolinones to model the reaction profile for the nucleophilic substitution of silicon (66). They developed a method to obtain similar structural coordinates in the solution phases using 13C and 29Si NMR spectroscopy by preparing a series of 2-quinolinone analogues which can be analyzed by both x-ray crystallography and solution NMR, providing a new method of structural correlation. Because there was excellent agreement between the results obtained by the two different methods, the authors have demonstrated the validity of NMR spectroscopy of solutions for structural correlation with the results of x-ray crystallography.
Treatment of 2-quinolinone with diethylaminetrimethylsilane was used to prepare the corresponding trimethylsilyl derivative (67). This was reacted with chloro(chlormethyl)dimethylsilane to give the chloro derivative, and with (bromomethyl(chloro)methyl- silane to give the bromo derivative. The chloro derivative was treated with antimony trifluoride to give the fluoro derivative, and with trimethylsilyl triflate to give the triflato derivative.
The x-ray crystal structure of these compounds was determined on a one circle diffractometer, equipped with an imaging plate system as detector (70). Graphite monochromated Mo-K radiation (-0.71073 ?) was used. Data collection was performed in a rotation mode. The raw intensity data were corrected for Lorentz and polarization effects, but not for absorption (71). Structure solutions were searched and refined by direct methods and by difference Fourier analyses. Hydrogen atoms were assumed in their idealized positions on their pivot arms, and atom form factors were taken from the literature, while second and third row elements were allowed to refine anisotropically.
NMR spectroscopy mapping was carried out on the solution phase of som...