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Controlling the Charge Transfer Mechanism and Efficiency by Means of Different C 70 Regioisomeric Adducts
Author(s) -
Plass Fabian,
Lukyanov Daniil A.,
Konev Alexander S.,
Kahnt Axel,
Amsharov Konstantin Y.,
Khlebnikov Alexander F.,
Guldi Dirk M.
Publication year - 2020
Publication title -
small structures
Language(s) - English
Resource type - Journals
ISSN - 2688-4062
DOI - 10.1002/sstr.202000012
Subject(s) - chemistry , structural isomer , ultrafast laser spectroscopy , adduct , electron acceptor , delocalized electron , fullerene , acceptor , porphyrin , photochemistry , electron transfer , femtosecond , computational chemistry , stereochemistry , organic chemistry , spectroscopy , laser , physics , quantum mechanics , optics , condensed matter physics
Here, differences stemming from two newly synthesized electron donor–acceptor conjugates, α‐ or β‐regioisomeric adducts featuring orthogonal arrangements of an electron‐donating free‐base porphyrin (H 2 P) and electron‐accepting C 70 , are reported. Key to a full‐fledged investigation in terms of both experiments and theory is the use of a rigid linker to separate the electron acceptor and donor. Both conjugates are experimentally investigated by means of femtosecond/nanosecond transient absorption measurements, which is further supported by radiation chemical studies based on pulse radiolysis. Significant regioisomeric differences are seen in the charge recombination kinetics, in general, which are as large as 1.4‐fold, and in the relative distributions of the charge recombination pathways, in particular, which reach nearly 1.5‐fold. Clearly, α‐regioisomers of C 70 adducts are much better suited for the construction of future energy conversion systems than β‐regioisomers; a fact that relates to the superior electron delocalization within the carbon caps of C 70 made out of “corannulenoid” fragments relative to the equator region of fullerenes featuring extended “phenanthrenoid” rings.