The dicationic complexes [IndCpMoL2]2+ (Ind = indenyl; Cp = cyclopentadienyl; 1, L2 =
dppe; 2, L = PMe3; 4, L2 = Bipy; 5, L2 = tBu2bipy; 6, L2 = H2biim; 7, L = CO and CNMe; 8,
L = CNMe; 9, L = CNtBu; 10, L = NCMe and NMF; 11, L = NMF) were synthesized from
[IndCpMoL‘2]2+ (L‘ = CO, NCMe), [IndCpMo(NCMe)Cl]BF4, or IndCpMoCl2 by ligand
substitution. The neutral complexes (η3-Ind)CpMoL2 (13, L2 = dppe; 14, L = PMe3; 15, L2 =
Bipy; 16, L = CO and CNMe; 17, L = CNtBu) were obtained upon reduction of the respective
dications with Cp2Co. (η
3-Ind)CpMo(dppe) (13) was also prepared by deprotonation of the
cyclopentadiene cation [IndMo(η4-C5H6)(dppe)]BF4
(12) with NEt3. The cyclic voltammograms
of the dications present one reversible 2e reduction step from Mo(IV) to Mo(II) except for 1,
2, and 6, in which cases two reversible 1e waves are observed. The ring-slipped complexes
(η
3-Ind)CpMoL2 and the parent dications present similar CV's. The X-ray crystal structures
of [IndCpModppe][BF4]2 and (η
3-Ind)CpMo(dppe) confirm the indenyl ring planar η5
coordination and slip-folded η3, respectively.