Document Type
Article
Publication Date
2025
Publication Title
The Journal of Organic Chemistry
Keywords
aromatic compounds, hydrocarbons, molecular structure, nuclear magnetic resonance spectroscopy, pyrroles
Abstract
Phenaliporphyrin, a new aromatic benziporphyrin derivative, has been synthesized from an annulated cyclopropane dialdehyde intermediate. Corey-Chaykovsky cyclopropanation of dimethyl acenaphthylene-1,2-dicarboxylate gave a cyclopropane diester, and this was converted to the corresponding bis-Weinreb amide. Reduction with lithium aluminum hydride afforded an unstable dialdehyde and subsequent acid-catalyzed condensation with a tripyrrane dicarboxylic acid, followed by oxidation with aqueous ferric chloride, gave the targeted porphyrinoid system. This involves ring expansion of the acenaphthylene precursor to generate the phenalene unit. Phenaliporphyrin exhibits a porphyrin-like UV–vis spectrum with a Soret band at 443 nm and a relatively intense Q-band at 601 nm. The proton NMR spectrum demonstrated that the system has a strong diamagnetic ring current, and the external meso-protons showed up downfield at 9.64 and 9.34 ppm while the internal C–H appeared upfield at −6.48 ppm. Although DFT calculations show that the phenalene ring is twisted to relieve steric interactions, single crystal X-ray diffraction analysis indicated that the macrocycle is nearly planar. The discrepancy was attributed to crystal packing forces and a distorted conformation is likely to be favored in solution. The aromatic properties for phenaliporphyrin were confirmed by nucleus independent chemical shift (NICS) calculations and anisotropy of induced current density plots.
Funding Source
This work was supported by the National Science Foundation under CHE-2247214. NSF is also acknowledged for providing funding for the departmental NMR spectrometers (CHE-0722385), X-ray diffractometer (CHE-2407904) and high-resolution mass spectrometer (CHE-1337497) under the Major Research Instrumentation (MRI) program. This article was published Open Access thanks to a transformative agreement between Milner Library and ACS.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
DOI
10.1021/acs.joc.5c02277
Recommended Citation
Jacob, S. O.; Harris, E. D.; Mathius, M. A.; AbuSalim, D. I.; Ferrence, G. M.; Lash, T. D. Synthesis of Phenaliporphyrin, a PAH-Porphyrin Hybrid, from an Acenaphthene-Fused Cyclopropane Dialdehyde. J. Org. Chem. 2025, 90 (49), 17422–17432. https://doi.org/10.1021/acs.joc.5c02277.
Comments
First published in The Journal of Organic Chemistry (2025):
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.joc.5c02277.