Some new rhodium(I)-aziridine complexes

Throughout the past decade our research group has been interested in coordination compounds of aziridine (Az = aziridine or ethylenimine, a three-membered ring. A previously reported Rh(I)-aziridine complex, iodotris(ethylenimine)rhodium(I), derived by the HI reduction of a Rh (III) compound provided the impetus for the work described here. If Rh(Az)_3I exists as empirically written, it will be a rare example of a coordinately-unsaturated and exclusively sigma-bonded Rh(I) complex. Generally, such low oxidation states are stabilized by one or more pi-bonding ligands. However, this compound lacks the stabilizing influence of such ligands. Subsequent attempts to duplicate the reported synthesis of this complex in order to examine more carefully its chemical and physical properties were unsuccessful. Consequently, a new approach has been devised using carbonyltris(ethylenimine)rhodium(I) chloride as an intermediate in the preparative scheme. Dicarbonylbis(ethylenimine)rhodium(I) chloride has also been prepared as a possible precursorin a continued study of Rh(Az)_3I. Unfortunately, the study was not completed due to aziridne poisoning suffered by M. R. Hoffmann; our positive results are presented here