IMPORTANCE OF STERIC EFFECTS UPON THE SYNTHESIS OF ((ETA(6)-ARENE)RUCL)-C,N-CYCLOMETALATED AMINES

The transmetallation reaction between [(eta(6)-arene)RuCl2](2) (eta(6) -arene = C6H6 (benzene) (1); 1-Me-4-Pr-i-C6H4 (cymene) (2); 1,2,4,5-Me (4)-C6H2 (durene) (3); 1,2,3,5-Me(4)-C6H2 (isodurene) (4)) and the ami noaryl-mercury derivatives Hg{Q-dmba}(2), (Q-dmba = 1-{C6H3-3-F-6-CH(2 )NMe(2)} (a); 1-{C6H3-3-Me-6-CH(2)NMe(2)} (b); 1-{C6H2-2,3-OCH3O-6-CH( 2)NMe(2)} (c); 1-{C6H2-2,4-(MeO)(2)-6-CH(2)NMe(2)} (d); 1-{C(6)H(4)CH( 2)NMe(2)} (e)) affords the corresponding C,N-cycloruthenated complexes [(eta(6)-arene)RuCl{Q-dmba}]. All complexes were characterised by H-1 and C-13(H-1) NMR. The reaction seems to be governed by steric rather than by electronic factors: an increase in the number of alkyl substi tuents in the eta(6)-arene ligand or the presence of bulky groups orth o to Hg in the starting material leads to a significant decrease of th e yields of the desired cycloruthenated products.