No abstract

No abstract

A series of 4-(X)-substituted naphthalimides (X ) ethenylFc, ethynylFc, piperidinyl, ethenylpiperidinyl, ethenylpyrrolidinyl) with ferrocenyl headgroups (R ) Fc(CH 2 ) n , n ) 1, 5, 11) and analogous ethenylFc, ethynylFc, and ethynylFc # (Fc # ) octamethylferrocenyl) compounds with a methyl headgroup have been investigated. These are the first 4-enamine-1,8-naphthalimides to be reported. Spectrochemical properties for all compounds are presented and the X-ray structures of 4-piperidinyl and 4-ethynylferrocenyl derivatives described. This series of donor-acceptor derivatives allows a correlation between the degree of internal charge separation, UV-vis and emission properties, and mediation by the organometallic redox couple. Charge separation increases in the order 4-amino , 4-CdCamino = 4-CtCFc = 4-CdCFc < 4-CtCFc # . The unsaturated spacer is the key influence on both λ flu and φ f , but λ flu is independent of the headgroup due to the imide node. In contrast, φ f shows a "distance" effect for the ferrocenyl headgroup, and as a result φ f can be "tuned"; dyads with the Fc(CH 2 ) 11 headgroup have φ f > 0.2. Solvatochromism data gives an excited state dipole of ∼8 D. An EPR study of radical anions provides a description of the SOMO. Through-space interaction between the ferrocenyl headgroup and the charge-separated excited state may account for some of the trends in EPR and φ f . In general, emission is decreased upon oxidation to the ferrocenium analogues.