THE STUDY OF ISOLOBAL DISPLACEMENT-REACTIONS - SYNTHESIS AND CHARACTERIZATION OF HETERONUCLEAR TRANSITION-METAL CLUSTERS [(ETA(5)-RC(5)H(4))(CO)(2)M] [(ETA(5)-R'C5H4)(CO)(2)M']FE(CO)(3)(MU(3)-S), [(ETA(5)-R'C5H4)(CO)(2)M']FE-2(CO)(3)(MU(3)-S) (M,M'=MO OR W) AND [(ETA(5)-MEO(2)CC(5)H(4))(CO)(2)W] [(ETA(5)-MEC(O)C5H4)(CO)(2)W]FE(CO)(3)(MU(3)-S)

The isolobal displacement reactions between cluster compounds [(eta(5) -RC(5)H(4)) (CO)(2)M]Fe(CO)(3)Co (CO)(3)(mu(3)-S) and group 6 metal an ions eta(5)-R'C5H4(CO)(3)M'(-) afforded eight heteronuclear transition -metal clusters [(eta(5)-RC(5)H(4) (CO)(2)M] [(eta(5)-R'C5H4) (CO)(2)M ']Fe(CO)(3)(mu(3)-S) (1a: R=CO(2)Et, M=W, R'=H, M'=Mo; 1b: CO(2)Me, W, C(O)Me, Mo; 1c: CO(2)Me, W, CO(2)Me, Mo; 1d: CO(2)Et, Mo, Me, W) and [(eta(5)-R'C5H4 (Co)(2)M']Fe-2(Co)(3)(mu(3)-S) (2a: R' = H, M' = Mo; 2 b: C(O)Me, Mo; 2c: CO(2)Me, Mo; 2d: Me, W). Similarly, the isolobal re action between [(eta(5)-MeO(2)CC(5)H(4)) (CO)(2)W]Fe(CO)(3)Co(CO)(3)(m u(3)-S) and eta(5)-MeC(O) C5H4(COW- gave three heteronuclear transitio n metal clusters a(5)-MeO(2)CC(5)H(4))(CO)(2)W][(eta(5)-MeC(O)C5H4) (C O)(2)W] Fe(CO)(3)(mu(3)-S) (1e), [(eta(5)-MeC(O)C5H4) (CO)(2)W]Fe-2(CO )(3)(mu(3)-S) (2e) and [(eta(5)-MeO(2) CC5H4) (CO)(2)W]Fe-2(CO)(3)(mu( 3)-S) (3). All the compounds 1a-e, 2a-e and 3 were fully characterized by elemental and spectroscopic analyses. In addition, the possible re action pathways for the formation of these products are preliminarily proposed.