Abstract
Phosphorus(V)-centered porphyrins (P(V)-porphyrins) are an important class of functional dyes in many fields of research, and axial ligands on the phosphorus atom affect the electronic properties of P(V)-porphyrins and add functions. Herein, we report on the synthesis and characterization of a hitherto unknown P(V)-porphyrin having hydrogen atoms as axial ligands (1(+)·PF(6) (-), PF(6) (-) is a counter anion). Synthesis of 1(+)·PF(6) (-) was achieved by treatment of dichloro-derivative (2(+)·Cl(-)) with LiAlH(4) followed by AgPF(6) via hydride reduction accompanied by one-electron reduction and one-electron oxidation. The porphyrin core of 1(+)·PF(6) (-) is nonplanar but considerably ruffled. The cyclic voltammogram of 1(+)·PF(6) (-) exhibits two reversible waves, which indicates redox couples among 1(+), neutral radical 1(•), and 1(-). Compound 1(+)·PF(6) (-) is tolerant toward air despite its PH(2) moiety due to the energetically low-lying HOMO (highest occupied molecular orbital) and σ(P-H) orbitals.