STRUCTURE OF 9,9'-BITRIPTYCYL

The molecular structure of 9,9'-bitriptycyl has been determined by X-ray crystallography and empirical force field calculations. Agreement is excellent for all bond lengths and angles except for the central bond, where the X-ray distance is 0.031 Å shorter than the calculated value. This discrepancy may be rationalized, in part at least, by invoking rehybridization of the central carbon atoms as a result of strain-induced distortions of valence bond angles; such electronic effects are not taken into account by current empirical force fields. © 1978, American Chemical Society. All rights reserved.