Abstract
AbstractMultifunctional molecular materials comprising porphyrins and fullerenes have served as perfect prototypes to study key aspects of natural photosynthesis starting at light harvesting and energy transfer processes all the way to charge separation, charge shift, and charge recombination. Herein, hexa‐peri‐hexabenzocoronenes (HBCs) are explored, decorated with one, two, and six porphyrins at their peripheral positions, within the context of replicating key steps of photosynthesis. The major focus of the investigations is to screen inter(porphyrin) communications across the HBC platform as a function of the substitution pattern and to optimize the intermolecular forces with fullerenes. To this end, the ground‐ and excited‐state features are investigated in the absence of C60 and C70 by employing an arsenal of spectroscopic methods. Further insights into inter(porphyrin) communications come from time‐dependent density‐functional theory (TDDFT) calculations. In the presence of C60 and C70, X‐ray crystallography, steady‐state and time‐resolved spectroscopy, and mass spectrometry corroborate exceptionally strong inter(porphyrin–fullerene) interactions in the solid, liquid, and gas phases. The experiments are backed‐up with DFT calculations of the geometrically optimized and energetically stable complex configuration.
Highlights
Porphyrin–fullerene electron donor– acceptor systems have been at the focal point of studies in recent decades.[1,2,3,4,5,6] Constituting a suitable platform for interdisciplinary investigations regarding energy and electron transfer reactions, numerous studies on covalent and noncovalent interactions fostered our understanding to replicate key aspects of natural photosynthesis.[7]
We investigated a full-fledged family of HBC–porphyrin conjugates with a broad arsenal of spectroscopic, crystallographic, and theoretical methods
HBC offers unique possibilities for realizing different substitution patterns, namely ortho, meta, and para, which are normally found in phenyl rings
Summary
Porphyrin–fullerene electron donor– acceptor systems have been at the focal point of studies in recent decades.[1,2,3,4,5,6] Constituting a suitable platform for interdisciplinary investigations regarding energy and electron transfer reactions, numerous studies on covalent and noncovalent interactions fostered our understanding to replicate key aspects of natural photosynthesis.[7]. Photoexcitation at 430 nm leads to similar results, but without forming any HBC-centered singlet excited state and without any HBC-to-ZnP energy transfer. The ZnP triplet excited state features dominate the transient absorption spectra with coexcited C60/C70 excited-state transients In accordance with these observations, global-target analyses of the raw data were run with a kinetic model (Figure 11) that involved coexcitations of, for example, complexed C60@2o and noncomplexed C60 and/or 2o. A faster adaptation of the geometry would lead to a lower fragmentation energy due to increasing interactions between the H2Ps. In C60@2oH2, C60 is encapsulated by both H2Ps and interacts with both of them and their respective tert-butyl groups (Figure S79, Supporting Information). Similar to the respective 2oH2 complexes, the magnitude of “optimized” formation energy is increased for the neutral C60@2mH2 (Table S11 and Figure S80, Supporting Information). The result is a small reorganization energy and a smaller energy barrier for the fragmentation relative to C60@2oH2 (Figure 16)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
