DEFORMATION DENSITY STUDIES OF RING-SYSTEMS .2. THE DEFORMATION DENSITY OF THE DIAZIRINE RING IN THE X-RAY STRUCTURE OF 3-[(P-NITROPHENOXY)METHYL]-3-CHLORODIAZIRINE

The crystal structure and electron density of 3-[(p-nitrophenoxy)methy l]-3-chlorodiazirine have been analyzed using single crystal X-ray dif fraction at 208 K with Mo K alpha radiation to a resolution of sin(the ta(max))/lambda = 1.126 Angstrom(-1). A total of 10 440 measured refle ctions gave 7742 unique reflections with R(m) = 0.026. A multipole ato mic density model was fitted to these reflections to give an R(F) = 0. 0311. The deformation density of the phenyl portion of the compound is as expected. The dynamic deformation density of the diazirine ring, h owever, suggests that the bonding in the three-membered ring is a comb ination of the classical severely-strained cr bonding system with a si gnificant contribution of a a donation from the N=N to an sp(2) carbon . This observation is placed in the context of similar proposals for t he bonding in cyclopropanes.