The effects of sigma(C-Se)-pi hyperconjugation in 1-methoxy- and 1-nitro-4-[(phenylselanyl)methyl]benzene

The structures of 1-methoxy-4-[(phenylselanyl)methyl]benzene, C14H14OSe, (1), and 1-nitro-4-[(phenylselanyl)methyl]benzene, C13H11NO2Se, (2), were determined at 130 K. The two structures, which differ in that (1) contains an electron-rich aromatic ring and (2) contains an electron-deficient aromatic ring, both adopt conformations which allow for σ(C-Se)-π hyperconjugation. However, although there are significant differences in the (77)Se chemical shifts for these two compounds, they do not display significantly different H2C-Se or H2C-C(ar) bond lengths, suggesting that the effects of σ(C-Se)-π hyperconjugation in (1) and (2) are not strong enough to be manifested in measurable differences in the structural parameters