STRUCTURAL STUDIES OF BIS(MU(2)-ACETOPHENONIMINATO)-BIS(TRICARBONYLIRON) BY NMR AND X-RAY-DIFFRACTION - DEVIATIONS FROM SYMMETRY IN ANTI AND SYN ISOMERS

Two distinct structural isomers obtained in the reaction of 1,4-dimeth yl-1,4-diphenyl-2,3-diazabuta-1,3-diene {(CH3)(Ph)C=N-}(2) with triiro n dodecacarbonyl were separated, characterized by NMR, and their molec ular structures were determined by X-ray diffraction. Only idealized s ymmetry in both resolved anti and syn forms have been observed Geometr y analysis indicated in the syn form a substantial deviation from symm etry, especially in the peripheral region of the molecule. This deviat ion is preserved in solution, as demonstrated by C-13 NMR.