Nonlinear Optical Properties of Ferrocene- and Porphyrin-[60]Fullerene Dyads

A series of novel [60]fullerene–ferrocene and [60]fullerene–porphyrin dyads, in which a fullerene and an electron donating moiety are attached through a flexible triethylene glycol linker are synthesized and their nonlinear optical (NLO) response studied. Specifically, the third‐order susceptibility χ(3) of all fullerene derivatives are measured in toluene solutions by the optical Kerr effect (OKE) technique using 532 nm, 35 ps laser pulses and their second hyperpolarizability γ are determined. All fullerene dyads studied exhibit enhancement of their NLO response compared to pristine fullerenes which has been attributed to the formation of a charge separated state. All experimentally measured hyperpolarizability γ values are also calculated by the semiempirical methods AM1 and PM3. A good correlation is found between the theoretical and experimental values, suggesting that simple semiempirical methods can be employed for the designing and optimization of the fullerene‐containing dyads displaying improved nonlinear responses. Improved responses: Novel fullerene dyads (see figure) exhibit an enhancement of their nonlinear optical response compared to pristine fullerenes. There is good agreement between the semiempirical calculations and the measured hyperpolarizability [by the optical Kerr effect (OKE)], suggesting that simple semiempirical methods can be employed for the design and optimization of fullerene dyads.