Synthesis of electron-deficient fluorinated porphyrins through scrambling: Characterization and quantitative crystal structure analysis

• We report the synthesis and characterization of fluorinated porphyrins.
• Crystal structures of Cu-A3B and Cu-cis-A2B2 porphyrins are reported.
• Intermolecular interactions analyzed quantitatively by Crystal Explorer.

MacDonald type 2 + 2 condensation of 5-(4-cyanophenyl)dipyrromethane with pentafluorobenzaldehyde in presence of BF3·OEt2 results in unexpected formation of fluorinated porphyrins namely, B4, H2T(PFP)P, 1; AB3, H2T(PFP)(CP)P, 2; cis-A2B2, cis-H2B(PFP)B(CP)P, 3 and A3B, H2(PFP)T(CP)P, 5 in addition to the expected trans-A2B2, trans-H2B(PFP)B(CP)P, 4 porphyrin through scrambling of the 4-cyano/pentafluoro phenyl substituents. The same reaction in TFA catalyst leads to non-scrambling condition and yields trans-A2B2 porphyrin. The complementary reactions were also performed using 5-(pentafluorophenyl)dipyrromethane to analyze the level of scrambling. The copper complexes of 3 and 5 have been structurally characterized by single crystal X-ray diffraction analysis and the role of weak intermolecular interactions in their crystal packing has been analyzed and quantified using Hirshfeld surface analysis.

A-DPM with B-CHO and its complimentary reaction in BF3·OEt2 results scrambling while TFA leads to non-scrambling condition, yields trans-A2B2 porphyrin.Figure optionsDownload as PowerPoint slide