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 porphyrin

Selective beta-polynitration of Zn-5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin, Zn(TDCPP), is achieved by controlled titration with the HNO3-CF3SO3H-(CF3SO2)(2)O system, and affords a full series of Zn porphyrins bearing one through to eight beta-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 beta-pernitrated Zn porphyrin Zn(TDCPN8P)(EtOH)(2). 2EtOH confirms the synthetic methodology.