BIS(ARYLIMIDO) COMPLEXES OF CHROMIUM(VI)

A synthetic entry into bis(arylimido) chromium(VI) chemistry is descri bed. Cr(NAr)(2)(NHBu(t))Cl (1; Ar= 2,6-(Pr2C6H3)-C-i) may be obtained (1) by treatment of Cr(NBu(t))(2)Cl-2 with two equivalents of 2,6-diis opropylaniline in pentane, or (2) via the reaction of Cr(NBu(t))(2)Cl- 2 with two equivalents of LiNHAr in Et(2)O. An X-ray structure determi nation on 1 reveals a pseudo-tetrahedral coordination geometry with Cr -N distances of 1.643(3) and 1.654(4) Angstrom for the imido groups an d 1.813(3) Angstrom for the tert-butylamido ligand; the substituents o f the amide are orientated perpendicular to the Cl-Cr-N(amido) plane. Compound 1 is readily converted to Cr(NAr)(2)Cl-2(2) by treatment with excess BCl2 in dichloromethane.