[Me2Si(C5Me4)2]MoH2 reacts with furan and benzofuran to yield products resulting from C–H bond cleavage, namely [Me2Si-
(C5Me4)2]Mo(g1-C-C4H3O)H and [Me2Si(C5Me4)2]Mo(g1-C-C8H5O)H, whereas the corresponding reactions of selenophene and
benzoselenophene yield products resulting from C–Se bond cleavage, namely [Me2Si(C5Me4)2]Mo(g2-C,Se-SeC4H4) and [Me2Si(C5-
Me4)2]Mo(g2-C,Se-SeC8H6). On this basis, the reactivity of the selenophene derivatives is analogous to that of previously reported
thiophene derivatives, while the reactivity of the furan derivatives is unique. DFT calculations indicate that C–E (E = O, S, Se) bond
cleavage is thermodynamically more favored than C–H bond cleavage for each of the chalcogen derivatives. As such, the calculations
provide evidence that C–O bond cleavage of the furan derivatives is not observed because of kinetic factors. DFT calculations also demonstrate
that the observation of C–S bond cleavage of thiophene by the ansa metallocene [Me2Si(C5Me4)2]MoH2 and C–H bond cleavage
by Cp2MoH2 is dictated by thermodynamic factors. Specifically, the Me2Si ansa bridge thermodynamically favors [Me2Si(C5Me4)2]-
Mo(g2-C,S-SC4H4) over [Me2Si(C5Me4)2]Mo(g1-C-SC4H3)H because the bridge promotes a shift in the coordination of the cyclopentadienyl
rings from g5-coordination towards g3-coordination and this thermodynamically unfavorable modification is stabilized by
sulfur-to-metal p-donation within [Me2Si(C5Me4)2]Mo(g2-C,S-SC4H4).