MIXED-LIGAND COMPLEXES OF RHENIUM .5. THE FORMATION OF NITRENE COMPLEXES BY CONDENSATION OF ACETONE AT COORDINATED NITRIDO LIGANDS - SYNTHESES AND STRUCTURES OF FAC-[RE(NC(CH3)2CH2C(O)CH3)X3(ME2PHP)2] COMPLEXES (X = CL, BR)

The reaction of rhenium(V)-mixed-ligand complexes of the general formula [ReN(Cl)(Me2PhP)2(R2tcb)] (HR2tcb = N-(N,N-dialkylthiocarbamoyl)benzamidine) with HCl or HBr in acetone initializes a condensation of the solvent and results in nitrene-like compounds as a consequence of a nucleophilic attack of the coordinated nitrido ligand on the condensed acetone. The chelate ligands are removed during this reaction and complexes of the type fac-[Re{NC(CH3)2CH2C(O)CH3}X3(Me2PhP)2] (X = Cl, Br) are formed. fac-[Re{NC(CH3)2CH2C(O)CH3}Cl3(Me2PhP)2] crystallizes triclinic in the space group P1; a = 8.575(4); b = 9.088(3); c = 18.389(9) angstrom; alpha = 75.67(3)-degrees, beta = 85.30(3)-degrees, gamma = 70.58(4)-degrees; Z = 2. A final R value of 0.031 was obtained on the basis of 6011 independent reflections with I greater-than-or-equal-to 2sigma(I). Rhenium is coordinated in a distorted octahedral environment with the three chloro ligands in facial positions. The rhenium-nitrogen bond (1,68(1) angstrom) is only slightly longer than typical Re-N bonding distances in nitrido complexes. fac-[Re{NC(CH3)2CH2C(O)CH3}Br3(Me2PhP)2] is isomorphous with the chloro complex. Triclinic cell with a = 8.625(4); b = 9.198(3); c = 18.581(5) angstrom; alpha = 75.62(3)-degrees, beta = 85.40(3)-degrees, gamma = 70.91(3)-degrees; Z = 2. The R value converged at 0.049 on the basis of 3644 independent reflections with I greater-than-or-equal-to 2sigma(I). fac-[Re{NC(CH3)CH2C(O)CH3}Cl3(Me2PhP)2] as well as fac-[Re{NC(CH3)2CH2C(O)CH3}Br3(Me2PhP)2] crystallizes in the noncentrosymmetric space group P1.