A new general method for selective β-polynitration of porphyrins; preparation and redox properties of Zn-porphyrins bearing one through to eight β-nitro substituents and X-ray structure of the first Zn β-pernitro porphyrinElectronic supplementary information (ESI) available: ORTEP plots for 1, bond distances and displacements from the plane of the porphyrin core. See http://www.rsc.org/suppdata/cc/b0/b004160m/

Abstract

Selective β-polynitration of Zn–5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin, Zn(TDCPP), is achieved by controlled titration with the HNO₃–CF₃SO₃H–(CF₃S O₂)₂O system, and affords a full series of Zn porphyrins bearing one through to eight β-nitro groups in high yield and exhibiting a wide range of reduction potentials (from −920 to +155 mV vs. SCE); an X-ray structure of the first reported β-pernitrated Zn porphyrin Zn(TDCPN₈P)(EtOH)₂·2EtOH confirms the synthetic methodology.