ChemRxiv
These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
Senge_PicketFencePor.pdf (2.38 MB)

Strategic Synthesis of ‘Picket Fence’ Porphyrins Based on Nonplanar Macrocycles

preprint
submitted on 23.01.2021, 16:39 and posted on 25.01.2021, 12:19 by Karolis Norvaisa, Kathryn Yeow, Brendan Twamley, Marie Roucan, Mathias O.. Senge
Traditional ‘picket fence’ porphyrin systems have been a topic of interest for their capacity to direct steric shielding effects selectively to one side of the macrocycle. Sterically overcrowded porphyrin systems that adopt macrocycle deformations have recently drawn attention for their applications in organocatalysis and sensing. Here we explore the combined benefits of nonplanar porphyrins and the old molecular design to bring new concepts to the playing field. The challenging ortho-positions of meso-phenyl residues dodecasubstituted porphyrin systems led us to transition to less hindered para- and meta-sites and develop selective demethylation based on the steric interplay. Isolation of the symmetrical target compound [2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetrakis(3,5-dipivaloyloxyphenyl)porphyrin] was investigated under two synthetic pathways. The obtained insight was used to isolate unsymmetrical [2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetrakis(2-nitro-5-pivaloyloxyphenyl)porphyrin]. Upon separation of the atropisomers, a detailed single-crystal X-ray crystallographic analysis highlighted intrinsic intermolecular interactions. The nonplanarity of these systems in combination with ‘picket fence’ motifs provides an important feature in the design of supramolecular ensembles.

Funding

Science Foundation Ireland (IvP 13/IA/1894)

Irish Research Council (GOIPG 2017/1172)

Technical University of Munich – Institute for Advanced Studies (Hans Fischer Senior Fellowship)

European Union’s Horizon 2020 research and innovation program (FET Open grant agreement No. 828779)

History

Email Address of Submitting Author

sengem@tcd.ie

Institution

Trinity College Dublin, the University of Dublin

Country

Ireland

ORCID For Submitting Author

0000-0002-7467-1654

Declaration of Conflict of Interest

The authors declare no conflict of interest.

Version Notes

Version 1.0

Exports