Nucleophilic and electrophilic reactions of C-5 cyclo-polyenes coordinated to the [CpMoL2](n+) fragment (n = 1,2; L = 1/2dppe, PMe3, P(OMe)(3), CO)

Reaction of several nucleophiles (R-) with the dications [Cp2MoL2](2+) (L = CO, PMe3, dppe) produces the cyclopentadiene complexes [CPMo(eta(4)-C5H5R)L-2](+) (L = dppe, R = H, CH3, CH2CN, CH2PPh3, SMe; L = CO, R = H, CH3, SPh, PMe3; L = PMe3, R = H). Excess nucleophiles only produces regio and stereospecific double addition to one Cp ring in the case of H-forming CpMo(eta(3)-C5H7)L-2 (L = CO, PMe3, dppe). [CpMo(eta(4)-C5H6)L-2](+) reacts with LiCuMe2 to give CpMo(eta(3)-C5H6Me)L-2 (L = dppe, CO) and [Cp'Mo(eta(4)-C5H6)(CO)(2)](+) reacts with NaSPh and PMe3 to give Cp'Mo(eta(3)-C5H6SPh)(CO)(2) (Cp' = Cp, indenyl) and [CpMo(eta(3)-C5H6PMe3)(CO)(2)]BF4 respectively. The structure of the exclusively formed conformers endo-[CpMo(eta(4)-C5H6)(dppe)]PF6 and endo-CpMo(eta(3)-C5H7)(dppe) was determined by NMR and X-ray crystallography and analyzed by EHMO calculations. The reverse H- abstractions from [CpMo(eta(4)-C5H6)L-2](+) and CpMo(eta(3)-C5H7)L-2 with Ph3C+ are specific in all cases except for CpMo(eta(3)-C5H7)(dppe) which gives oxidative decomposition to [Cp2Mo(dppe)]L-2 and [CpMo(dppe)(2)](2+). All the complexes [CpMo(eta(4)-C5H5R)L-2](+) and CpMo(eta(3)-C5H7)L-2 (L = CO, PMe3, dppe) as well as their C6 ring congeners [CpMo(eta(4)-C6H8)(CO)(2)](+) and CpMo(eta(3)-C6H9)(CO)(2) have irreversible cyclovoltammograms. Nucleophilic attacks of Me3NO/NCMe and PMe3 to [CpMo(eta(4)- C6H8)(CO)(2)](+) gave [CpMo(eta(4)-C6H8)(NCMe)(2)]BF4 and [CpMo(eta(3)-C6H8PMe3)(CO)(2)]BF4 respectively. Both were crystallographically characterized. (C) 1997 Elsevier Science S.A.