Preferential Formation of Side‐Pocket‐Substituted Zinc Phthalocyanines Emitting Beyond 800 nm

Abstract

A series of zinc (1,4,8,11,15,18,22,25‐octabutoxy)phthalocyanine (2) complexes that spontaneously form 5‐coordinate complexes with anionic axial ligands neutralized with side‐pocket cations, of the form Cation‐PcZnX (X=Cl, OAc; Cation=H+ or Li+), was synthesized and structurally characterized. The side‐pocket protonation of the axial‐chloride species pushed the emission maximum from 760 nm (for axial ligand‐free 2) to 826 nm, well into the NIR region. A 1D‐coordinated chain bridged by lithium and chloride atoms was isolated and structurally characterized, representing the first side‐pocket metalated PcM species. This preferential formation of axially substituted [PcZnX]− “ate” complexes and their sequestration of both protons and lithium cations, opens a new series of materials with unique structural and electronic properties. Furthermore, their ability to both absorb and emit in the NIR region makes them desirable for numerous applications.