Functional solitare- and trans-hybrids, the synthesis, characterization, electrochemistry and reactivity of porphyrazine/phthalocyanine hybrids bearing nitro and amino functionality

Abstract

We report here for the first time a new and improved approach to the complete synthesis and characterization of the unsymmetrical metallo- and metal-free phthalocyanine/ porphyrazine (Pz/Pc) hybrids bearing peripheral nitro or amine functionality, H-2[Pz(n-Pr)(6)(BzNO(2))] or H-2[Pz(n-Pr)(4)(BzNO(2))(2)] where Bz = benzo, n-Pr = n-propyl, fused on the one or two benzenoid ring which form from the reaction of two different precursors, 3,4-bis-(n-propyl)-pyroline-2,5-diimine and 6/7-nitro-1,3,3-tricholoro isoindoline, with the base-catalyzed direct condensation method. The direct condensation method used in this study enable us to skip magnesium porphyrazine (MgPz) stage and limits the formation of undesired hybrid compounds when compared with cross-condensation method. Centrally metallated solitare- and trans-Pz/Pc hybrids, M[Pz(n-Pr)(6)(BzNO(2))] or M[Pz(n-Pr)(4)(BzNO(2))(2)] (M = Zn(lI) or Mn(II)), synthesized in this study are somewhat more soluble than the free ones. Metallo Pz/Pc hybrids were prepared by treatment of free-soitare and trans hybrids with the appropriate metal salts in anhydrous solvent mixtures. We observed that the solubility of solitare- and/or trans-PzlPc hybrids increases after nitro-substituted Pz/Pc hybrids are reduced to amine substituted ones. The reactivity of the NH2 group of the solitare-Zn[Pz(n-Pr)(6)(BzNH(2))] was tested by the condensation with ferrocenecarboxyaldehyde resulting in the formation of the ferrocene-substituted hybrid. The newly synthesized compounds have been characterized by elemental analaysis, FT IR, H-1 NMR, UV-vis and MS spectroscopy. Electrochemical measurements of the complexes characterized in this study showed that the attachment of NO2 and NH2 moieties at the periphery makes a monitorable effect on redox properties of the macrocycle and metal center. Copyright (C) 2003 Society of Porphyrins & Phthalocyanines.