SYNTHESIS OF RUTHENIUM AMIDE COMPLEXES BY NUCLEOPHILIC-ATTACK ON ORTHO-METALATED IMINE LIGANDS

The cationic ortho-metalated imine complexes, (eta-6-C6R6) activated Ru(R')N = C(R'')C6H4(L) (R = Me, H; R' = Ph, Et, Me; R'' = H, Me; L + PMe3, CO), 1, are formed in the reaction of (C6R6)RuCl2(L) with 2 equiv of imine and 2 equiv of AgBF4. These complexes react with powerful nucleophiles [Li(Bu(t)O)3AlH,RLi] via attack at the imine carbon atom, giving the neutral ortho-metalated amide complexes C6R6 activated Ru(R')-NC(R'')(Nu)C6H4(L). The nucleophilic attack occurs with high (> 98%) diastereoselectivity when the nucleophile differs from the substituent on the imine carbon. The molecular structures of [(eta-6-C6Me6) activated Ru(Ph)N = (CH)C6H4(PMe3)][BF4], 1a, and (eta-6-C6Me6) activated Ru(Ph)NC(H)(Me)C6H4(PMe3), 2a, were determined by X-ray diffraction. Complex 1a crystallizes in space group P2(1)/c (No. 14) with cell parameters a = 10.893 (2) angstrom, b = 14.507 (1) angstrom, c = 17.568 (3) angstrom, beta = 100.40 (1)-degrees, Z = 4, R = 0.025, and R(W) = 0.028. Compound 2a crystallizes in space group P2(1)/c (No. 14) with cell parameters a = 16.803 (3) angstrom, b = 9.306 (2) angstrom, c = 18.077 (3) angstrom, beta = 109.65 (1)-degrees, Z = 4, R = 0.061, and R(W) = 0.060.