Macrocyclic Dyads Based on C₆₀ and Perylenediimides Connected by Click Chemistry

Abstract

Two sets of perylenediimide‐[60]fullerene dyads PDI‐C60 connected through 1,2,3‐triazole units have been synthesized and characterized. The cyclic dyad PDICl4‐C60 has four chlorine atoms in the 1,6,7,12‐PDI positions, whereas the cyclic dyad PDIPip2‐C60 has two piperidine units in the 1,7‐PDI positions. On the other hand, PDICl4‐C60 and PDIPip2‐C60 dyads were synthesized as linear counterparts with the same substitution pattern. Also, a C60‐PDICl4‐C60 triad has been prepared. A small interaction between C60 and PDI moieties in the ground state was detected by UV/vis and electrochemical measurements in both PDI‐C60 cyclic systems. The occurrence of photoinduced energy‐transfer processes between PDI and C60 units was confirmed by time‐resolved emission and transient absorption techniques. Femtosecond laser flash photolysis showed energy transfer from 1PDI* to C60 followed by intersystem crossing from 1C60* to 3C60* in the case of the PDICl4‐C60 systems. The energy transfer rate for PDICl4‐C60 in the cyclic dyad and the triad is one order of magnitude faster than that in PDICl4‐C60 in the linear dyad. The fast energy transfer rate together with the enhanced molar absorption coefficient by perylenediimide functionalization will be highly beneficial for applications as acceptors in polymer solar cells. On the other hand, no electron transfer from the donor PDIpip2 units to the acceptor C60 moiety was detected in the case of PDIPip2‐C60 dyads.

The Green Box: An Electronically Versatile Perylene Diimide Macrocyclic Host for Fullerenes

“…Perylene diimides (PDIs) represent a class of chemically, thermally and photophysically stable organic dye molecules. − Their rich photo- and electrochemistry provides a wide range of visible light absorptions, characteristic long-lived excited states, and the ability to undergo efficient energy and electron transfer reactions, making them ideal components in synthetic donor–acceptor assemblies. − However, the covalent − or noncovalent ,, linking of PDI derivatives with C 60 fullerene has generated dyads in which negligible electron communication has been observed spectroscopically in the ground state ,− ,,,− while energy transfer was the predominant relaxation pathway for the excited state. − ,,,,, This is because, like fullerenes, archetypal PDIs are benchmark electron deficient aromatic molecules . Fortunately, their electronic properties can be modulated such that the incorporation of electron-donating pyrrolidine heterocycles in two of the bay positions of the perylene core causes a large, negative shift in oxidation potential to produce an electron-rich PDI .…”

Tunable and highly efficient light-harvesting antenna systems based on 1,7-perylene-3,4,9,10-tetracarboxylic acid derivatives

“… 15 In addition, the strong absorption of PBIs has been successfully utilized to improve the spectral coverage of C 60 . 17 An unfavorable feature of PBI dyes is their high electron deficiency, 16 a and therefore PBI assemblies tend to undergo facile charge-separation when PBIs are coupled with even moderately electron-rich chromophores. 18 In addition, the strong tendency of PBIs to form π–π aggregates is a severe limitation that needs to be accounted for in the design of molecular PBI based arrays.…”

Charge separation and charge recombination photophysical studies in a series of perylene–C60linear and cyclic dyads

“…Moreover, PDI and C 60 have also been linked to form dyads or triads, where usually PDIs acted as electron acceptors, 10 while only in very few examples PDIs worked as electron donors. 11 Recently, we have synthesized PDI-C 59 N and PDI-C 60 dyads, which take advantage of the electron donor character of the pyrrolidinyl PDI derivative. The PDI-C 59 N dyad undergoes an efficient intramolecular photoinduced electron transfer reaction in PhCN to afford a 400 ps-lived CS state, while PDI-C 60 achieved a 3 times shorter CSS lifetime, showing the influence of the nitrogen atom in the photoinduced electron-transfer process.…”