A series of arenecyclopentadienyl complexes, i.e., [Ru(eta(5)-C(5)R(5)
)(eta(6)-arene)](+) (1, R = H, arene = C6H6; 2, R = Me, arene = C6H6;
3, R = H, arene = C(6)H(3)Me(3); 4, R = Me, arene = C(6)H(3)Me(3); 5,
R = H, arene = C(6)Me(6); 6, R = Me, arene = C(6)Me(6)) was studied by
cyclic voltammetry. These compounds are capable of both oxidation and
reduction. The reduction potential values depend on the number of met
hyl groups in the complex. Reduction of benzene complexes 1 and 2 by s
odium amalgam in THF leads to the formation of decomplexation products
, the addition of hydrogen to benzene, and dimerization of the benzene
ligands. Both chemical and electrochemical reductions of mesitylene c
omplexes 3 and 4 result in dimeric products [(eta(5)-C(5)R(5))Ru(mu-et
a 5:eta 5-Me(3)H(3)C(6)C(6)H(3)Me(3))Ru(eta(5)-C(5)R(5))] (14, R = H;
15, R = Me). The action of sodium amalgam on compound 5 gives products
of hydrogen addition to both hexamethylbenzene (17) and cyclopentadie
nyl (18) ligands along with the major product, the dimer -eta(5):eta(5
)-Me(6)C(6)C(6)Me(6))Ru(eta(5)-C5H5)] (16). In contrast to 5, its perm
ethylated analog 6 is only capable of adding hydrogen to the hexamethy
lbenzene ligand.