Synthetic Approaches to a Variety of Covalently Linked Porphyrin−Fullerene Hybrids

Abstract

There is substantial interest in dyads in which C(60) is covalently linked to electron donors, such as porphyrins, which absorb light strongly in the visible region. We present here the details of the syntheses of such compounds, which can be broadly organized into categories depending upon the nature of the linker joining the two chromophores. The structural aspects of intramolecular electronic interaction that we have sought to explore have dictated the synthetic strategies employed to generate these classes of molecules. Flexible glycol linkers were used to allow close approach between the fullerene and porphyrin, facilitating through-space interactions. These linkers also allowed studies of the effects of metal cation complexation. Naphthalene and alkyne linkers were used to examine the possible effects a conjugated or aromatic linker might have on photophysical properties. Finally, steroids were used as linkers in dyads expected to possess a large distance between the two chromophores, in which only through-bond interactions between the fullerene and porphyrin should be possible.

Organofullerene Materials

“…Photoinduced electron transfer generally takes place easily in fullerene-porphyrin hybrid systems.Attention has been paid to the construction of rigidly linked systems in which the porphyrin and fullerene units are in enforced close proximity [195][196][197][198] or are forced apart [199][200][201][202]. Representative examples of dyads, where flexible linkers allow the porphyrin unit to approach really close to the fullerene moiety, include strapped "parachute" hybrids that have been synthesized via Bingel reaction conditions [195][196][197][198].…”

“…Representative examples of dyads, where flexible linkers allow the porphyrin unit to approach really close to the fullerene moiety, include strapped "parachute" hybrids that have been synthesized via Bingel reaction conditions [195][196][197][198]. On the other hand, steroid linkers used in independent studies were designed to provide a rigid polycyclic spacer capable of separating covalently linked donor (Ru-bipy complex or porphyrins) and acceptor (fullerene) systems well beyond the range of the van der Waals contact [199][200][201][202]. The synthesis of the latter systems was performed following the methodology of 1,3-dipolar cycloaddition of azomethine ylides to C 60 .…”

Electrochemical, theoretical, and morphological studies of antioxidant fullerosteroids

“…Various shapes of amphiphilic fullerene-based functional nanostructured materials, including wires [9], rods [10], tubes [11], sheets [12], spheres [13], fibers [14], or vesicles [15] are formed by solvent or temperature control. Contrary to the multitude of fullerene derivatives that have so far been published, only a few examples of fullerenes bearing different steroid moieties have been reported [16][17][18][19][20][21][22][23]. Such systems have all important characteristics typical for self-assembling process, primarily a large hydrophobic surface area that can provide an efficient platform for the formation of highly organized structures.…”

Face‐to‐Face Alignment of Porphyrin/Fullerene Nanowires Linked by Axial Metal Coordination

“…Up to now, a great variety of porphyrin/fullerene family, from dyads, [7][8][9][10][11][12][13][14][15][16][17][18] triads [19][20][21][22][23] to oligomers, [24][25] which involved covalent or noncovalent linkages have been widely constructed and used to adjust the distance and orientation between porphyrin and fullerene unit for efficient PET. There are mainly two alignments between porphyrin and fullerene units: one is parallel face-to-face alignment, another is perpendicular edge-to-face alignment.…”