FRONTIER ORBITAL INTERACTIONS OF ELECTRON PUSHING AND DRAWING SUBSTITUENTS WITH FERROCENYL GROUP

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)].