Addition of cyclopropenylium and tropylium ions to cyclooctatetraene-cobalt and -rhodium cyclopentadienyl complexes
Abstract
Cyclopropenylium ions [C3R′3]+(R′= Ph or But) react with [Co(η4-cot)(η-C5R5)](R = H or Me, cot = cyclooctatetraene) to give [M{η5-C8H8(C3R′3)}(η-C5R5)]+3(M = Co; R = H, R′= Ph; R = Me, R′= Ph or But); X-ray structural studies on 3(M = Co, R = H, R′= Ph) show an exo-cyclopropene substituent on the cyclooctatrienyl ring. The reaction of [C3Ph3]+ with [Rh(η4-cot)(η-C5Me5)] gives a similar product 3(M = Rh, R = Me, R′= Ph) which rearranges to an unknown isomer 5 whereas [Rh(η4-cot)(η-C5H5)] undergoes electrophilic substitution at the cyclopentadienyl ring to give [Rh(η2,η3-C8H9){η-C5H4(C3Ph3)}]+4. The addition of [C7H7]+ to [Co(η4-cot)(η-C5R5)](R = H or Me) gives [Co{η5-C8H8(C7H7)}(η-C5R5)]+6(R = H or Me) which, in the case of 6(R = Me), rearranges to the 1,2,3,3a-tetrahydropentalenyl complex [Co{η5-C8H8(C7H7)}(η-C5Me5)]+7. Finally, the reactions between [Rh(η4-cot)(η-C5R5)](R = H or Me) and [C7H7]+ give [Rh(η2,η3-C8H9){η-C5H4(C7H7)}]+8 and [Rh{η2,η3-C8H8(C7H7)}(η-C5Me5)]+9 respectively.