Ys. Jiang et al., FRONTIER ORBITAL INTERACTIONS OF ELECTRON PUSHING AND DRAWING SUBSTITUENTS WITH FERROCENYL GROUP, Science in China. Series B, Chemistry, life sciences & earth sciences, 40(3), 1997, pp. 236-244
The frontier orbital interactions of electron pushing and drawing subs
tituents with ferrocenyl group were analyzed based on the electrochemi
cal, UV-visible spectral and spectroelectrochemical results of five fe
rrocene derivatives, R-Fc-A(1)(PI), A(1)-Fc-A(1)(PII), D-Fc-R (PIII),
D-Fc-A(1)(PIV) and D-FcA(2)(PV) (R, CH2OH; A(1), CHO; A(2), CH=C(CN)(2
) and D, (C18H37)(2)N-C6H4-CH=CH) It was found that there are strong i
nteractions of the LUMO (pi(A)) of electron drawing substituents with
le(2g)(d(xy), d(x2-y2)) and e(2a)(phi(4a), phi(5u)) Of the ferrocenyl
group because the energy levels of pi(A) and e(2g), e(2u) of (Cp-)(2
) are close, which lower not only the energy levels of bonded orbits,
pi A + [phi(4u)] and d(x2-y2) + [pi(A)*] of PI, PII, PIV and PV obvio
usly, bur also those of their non-bonded orbit, d(xy). For PIII, PIV a
nd PV, there are strong interactions of HOMO (pi(D)) of the electron p
ushing substituent with le(1u), (phi(2u), phi(3u)) of the ferrocenyl g
roup because the levels of pi(D) and e(1u) of (Cp-)(2) are close, whic
h result in the formation of anti-bonded orbit, pi(D) - [phi(3u)], and
bonded orbit, phi(3u) + [pi(D)].