Synthesis and Photoinduced Energy‐ and Electron‐Transfer Processes of C₆₀–Oligothienylenevinylene–C₇₀ Dumbbell Compounds

Abstract

Unsymmetric dumbbell molecules based on N-methylpyrrolidine[60]fullerene, oligothienylenevinylenes (nTV; n=2, 4), and N-methylpyrrolidine[70]fullerene, namely, C(60) -nTV-C(70) were synthesized and their photophysical properties were studied. In nonpolar solvents, photoinduced energy-transfer process predominantly takes place from the singlet excited state of nTV to C(60) and C(70) , as was confirmed by time-resolved emission and transient absorption spectroscopy. In polar solvent, charge-separation processes take place instead of energy transfer. The generated charge-separated radical-ion pairs decay to the neutral molecules by a fast charge-recombination process; for n=4, a rate constant of 2×10(7) s(-1) and lifetime of 50 ns were evaluated.

Tethered bis-pyrrolidine additions to C70: Some unexpected and new regioisomers

“…Based on this pattern, the chemical shift of the signals and by comparison to the previously reported 1 H NMR spectrum of compound B (Fig. 2a, cis-2 H endo-H endo) [24,29,32], we suggest that compounds 1 and 2 exhibit the same endoeendo conformation. UV/vis spectroscopy is a useful tool to assign fullerene isomers since unique absorption patterns are observed for each derivative based on the addition sites and not on the nature of the addends.…”

“…showed similar UV/vis absorption spectra to that reported for the a-1-b and a-1-a regioisomers [32], respectively (see ESI) [31].…”

PffBT4T-2OD Based Solar Cells with Aryl-Substituted N-Methyl-Fulleropyrrolidine Acceptors

“…Other techniques such as HPLC can further confirm the isomeric nature of these mixtures. For instance, Urbani et al [37] have prepared C70-fuleropyrrodines with a similar approach here described and confirmed the presence of two kinds of isomeric products, namely, α and the β-types. However, differentiation within the α isomers or the β isomers was not possible.…”

“…We observed that the solubility of the resulting C 70 derivatives was greatly improved when compared with the solubility of the C 60 derivatives: while derivatives 70a-70d [37] were soluble in dichloromethane, derivatives 60a-60d were far less soluble, and only solvents such as toluene and CS 2 could dissolve them. The final products were separated from the unreacted starting material (C 60 or C 70 ) and other by-products by silica gel chromatography using a mixture of toluene/hexane.…”

Free-base porphyrin and [60]fullerene linked by oligomeric ethylenedioxythienylenevinylene bridge

“…p-Conjugated oligomers as oligothiophene (OT) [5] and oligophenylenevinylene (OPV) [6] moieties have been shown to act as long distance molecular wires in the efficient photoinduced electron transfer from the porphyrin chromophore to the fullerene. Recently, we have described the use of oligothienylenevinylene oligomers (nTVs) [7], where the thiophene moieties was substituted by alkyl chains, as efficient bridges in donor-donor [8], acceptoracceptor [9] or donor-acceptor [10] systems showing an attenuation factor for electron transfer as low as 0.016 Å -1 [11]. The functionalization of thiophenes with ethylenedioxy groups produced the well known 3,4-ethylenedioxythiophene (EDOT).…”