Anion binding properties of N-confused porphyrins at the peripheral nitrogen

Abstract

Ni(II), Pd(II), and Cu(II) complexes of N-confused porphyrin (NCP) exhibit anion binding properties through a hydrogen bonding interaction at the peripheral NH of confused pyrrole ring. The binding constants of the tetrakis(pentafluorophenyl)-NCP metal complexes (1-M, M = Ni, Pd, Cu) for various halide anions in CH 2C1 2 increase in the order of F - > Cl - > I -, respectively. Zwitterionic resonance form of the NCP complexes as well as interactions between halide anions and a pentafluorophenyl group are suggested to be important for efficient anion binding.