AN ANALYSIS OF DIASTEREOTOPIC PROTONS IN 2-HALODIMETHYLAMINOMETHYLFERROCENES

The two factors, conformational preference and intrinsic asymmetry, that contribute to geminal group magnetic nonequivalence in asymmetric compounds have been the topic of much conjecture. Synthesis of the 2-halodimethylaminomethylferrocenes gave us a series of compounds that should in fact minimize the alteration of electronic factors and maximize the relative importance of conformational preferences brought about by steric interactions. The results suggest that there is a steric interaction, but not in the “hard-core” sense of the word. The data do, however, suggest that there is a significant contact effect and a negligible anisotropic effect due to the halogen. © 1969, American Chemical Society. All rights reserved.