Long-range electronic communication in free-base meso-poly(ferrocenyl)-containing porphyrins.

H2FcPh3P [FcPh3P = 5-ferrocenyl-10,15,20-triphenyl porphyrin(2-)], cis-H2Fc2Ph2P [cis-Fc2Ph2P = 5,10-bisferrocenyl-15,20-diphenyl porphyrin(2-)], trans-H2Fc2Ph2P [trans-Fc2Ph2P = 5,15-bisferrocenyl-10,20-diphenyl porphyrin(2-)], and H2Fc3PhP [Fc3PhP = 5,10,15-trisferrocenyl-20-phenyl porphyrin(2-)] along with H2TPP [TPP = 5,10,15,20-tetraphenylporphyrin] and H2TFcP [TFcP = 5,10,15,20-tetraferrocenyl porphyrin(2-)] were isolated from the direct cross-condensation reaction between pyrrole, benzaldehyde, and ferrocene carboxaldehyde or from the reaction between ferrocenyl-2,2′-dipyrromethane and benzaldehyde, suggesting a scrambling reaction mechanism for the last approach. All compounds were characterized by UV−vis, MCD, and NMR spectroscopy; APCI MS and MS/MS methods; as well as high-resolution ESI MS spectrometry. The conformational flexibility of ferrocene substituents in all compounds was confirmed using variable-temperature NMR and computational methods. DFT calculations were employed to understand the...