Porphyrin Pincer Complexes: Peripherally Cyclometalated Porphyrins and Their Catalytic Activities Controlled by Central Metals

A series of heterobimetallic porphyrin pincer palladium complexes have been synthesized through direct cyclometalation of β,β‘-dipyridylporphyrin. X-ray analyses elucidated their highly distorted structures of porphyrin cores induced by the outer metalation. The catalytic activity has been investigated in the typical Heck reaction of iodobenzene with butyl acrylate. These complexes exhibit markedly different catalytic activities in the initial phase of the reaction, depending on the central metals.