Synthesis and Photophysical Properties of Steroid-Linked Porphyrin−Fullerene Hybrids

Abstract

[structure: see text] The photophysical properties of porphyrin-linked fullerene hybrids have generated significant interest, and a number of these hybrids synthesized by this group and others have been extensively characterized with respect to energy and charge-transfer processes that take place upon photoexcitation. Present studies of steroid-linked dyads demonstrate the extent to which through-bond effects operate in these systems.

Metal-chelating capacities attached to fullerenes

“…4, 6 and 7), an acceleration of the formation of the C 60 − P + state by a factor 3 was found [15,16]. Furthermore, upon removing the carbon carbon double bonds in the steroid linker in 8, quenching of the porphyrin excited states decreased significantly [17].…”

Steroid-photosensitizer conjugates: Syntheses and applications

“…Thus a steroid-linked porphyrin-fullerene dyad system, rigidly separated by an androgen moiety, has been reported [41]. Synthesis of hybrid molecules 47-49 starts with the Prato reaction, providing a facile route to the steroidal fullerene-pyrrolidine precursors via azomethineylide addition to C 60 .…”

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 .…”