Multiple‐Porphyrin Functionalized Hexabenzocoronenes

Abstract

Porphyrin–hexabenzocoronene architectures serve as good model compounds to study light‐harvesting systems. Herein, the synthesis of porphyrin functionalized hexa‐peri‐hexabenzocoronenes (HBCs), in which one or more porphyrins are covalently linked to a central HBC core, is presented. A series of hexaphenylbenzenes (HPBs) was prepared and reacted under oxidative coupling conditions. The transformation to the respective HBC derivatives worked well with mono‐ and tri‐porphyrin‐substituted HPBs. However, if more porphyrins are attached to the HPB core, Scholl oxidations are hampered or completely suppressed. Hence, a change of the synthetic strategy was necessary to first preform the HBC core, followed by the introduction of the porphyrins. All products were fully characterized, including, if possible, single‐crystal XRD. UV/Vis absorption spectra of porphyrin‐HBCs showed, depending on the number of porphyrins as well as with respect to the substitution pattern, variations in their spectral features with strong distortions of the porphyrins’ B‐band.

A Hexabenzocoronene‐Based Helical Nanographene

“…These results complement our previous findings, in which related nitrogen‐doped HBC‐like [5]helicenes were formed, however, controlled by electronic effects . The chiral separation and characterization as well as the usage of the twisted nanographene motif of 7 as a platform for further functionalized hybrid materials, for example, analogous architectures to our previously reported porphyrin‐HBCs, are currently under investigation.…”

A Functional Hexaphenylbenzene Library Comprising of One, Three, and Six Peripheral Rylene‐Diimide Substituents

“…One reason could be the pronounced electron deficiency of the corresponding HPB cores, caused by the increased number of electron withdrawing/accepting rylene‐diimide substituents. As a result, oxidative cyclodehydrogenation is prevented, which is in accordance with observations found for multiple‐porphyrin functionalized HBCs [21] . However, we were successful to synthesize mono‐substituted rylene‐diimide‐HBCs (Scheme 3).…”

Addressing Environmental Challenges of Porphyrin Mixtures Obtained from Statistical Syntheses

“…For this purpose, we enlarged our library ( Figure 6), by the synthesis of five more porphyrin mixtures (P2-P6), which comprise of commonly utilized unsymmetrical porphyrins. [2,[13][14][15]19,[37][38][39][40][41][42][43][44][45][46][47] The overall yields are summarized in Table 2, together with an overview on the purification parameters, obtained for all porphyrin mixtures. Spectroscopic data of all isolated porphyrins are listed in the Supporting Information.…”