Synthesis of an iridium porphyrin amido complex

Abstract

A synthetic route for iridium porphyrin amido complexes has been established. Treatment of a THF solution of Ir(ttp)(CO)Cl (1) (ttp = 5,10,15,20-tetrakis(p-tolyl)porphyrinato dianion) with an aqueous mixture of NaOH and NaBH4, followed by 2-iodoethanol leads to the clean formation of the β-hydroxyethyl complex Ir(ttp)(C2H4OH) (2) in 92% yield. Heating a pyridine solution of complex 2 in the presence of ca. 5–10 equiv. of phthalimide (HNC8H4O2; HPhth) leads to the formation of Ir(ttp)(C5H5N)(CH2CH2Phth) (3). The replacement of pyridine by THF as the reaction solvent leads to the formation of the THF adduct Ir(ttp)(THF)(Phth) (4), which has been characterized spectroscopically. Heating a solution of 4 in pyridine leads to the formation of Ir(ttp)(C5H5N)(Phth) (5), which has been isolated in 72% yield. Complexes 3 and 5 have been characterized by X-ray crystallographic studies. Complexes 4 and 5 are rare examples of monomeric late transition metal-amido complexes and are the first examples of iridium-amido complexes featuring a porphyrin as a supporting ligand.