Synthesis, Structure and Properties of a Five‐Coordinate Oxophosphorus(V) meso‐Triphenylcorrole

Abstract

AbstractTreatment of six‐coordinate (5,10,15‐triphenylcorrole)dihydroxyphosphorus(V) [P(TPC)(OH)2] with trifluoroacetic acid (TFA) in CH2Cl2 for 30 min at room temperature followed by recrystallization gave stable five‐coordinate (5,10,15‐triphenylcorrole)oxophosphorus(V) [P(TPC)O] in quantitative yield. The formation of [P(TPC)O] from [P(TPC)(OH)2] in the presence of TFA was also monitored by NMR, absorption and fluorescence spectroscopic titration studies. The structure of the isolated [P(TPC)O] was confirmed by X‐ray crystallography. In [P(TPC)O], the corrole ring is distorted, and the PV ion is displaced by 0.456 Å from the N4 plane towards the axial oxygen atom. This is unlike six‐coordinate (5,10,15‐triphenylcorrole)dimethoxyphosphorus(V) [P(TPC)(OCH3)2], in which the PV ion lies in the porphyrin plane. NMR, absorption and fluorescence spectroscopy and electrochemical studies indicate that [P(TPC)O] exhibits interesting and distinct properties, which differ from the six‐coordinate [P(TPC)(OCH3)2]. Attempts to reduce the PV complex [P(TPC)O] to its corresponding PIII complex by treating it with LiAlH4 resulted in the formation of six‐coordinate (5,10,15‐triphenylcorrole)dihydridophosphorus(V) [P(TPC)H2].