meso-(2-Pyridyl)-boron(III)-subporphyrin: Perimeter Iridium(III) Coordination

Abstract

Peripherally metalated porphyrinoids are promising functional π-systems displaying characteristic optical, electronic, and catalytic properties. In this work, 5-(2-pyridyl)- and 5,10,15-tri(2-pyridyl)-B^III -subporphyrins were prepared and used to produce cyclometalated subporphyrins by reactions with [Cp*IrCl₂ ]₂ , which proceeded through an efficient C-H activation to give the corresponding mono- and tri-Ir^III complexes, respectively. While the mono-Ir^III complex was obtained as a diastereomeric mixture, a C₃ -symmetric tri-Ir^III complex with the three Cp*-units all at the concave side was predominantly obtained in a high yield of 90 %, which displays weak NIR phosphorescence even at room temperature in degassed CH₂ Cl₂ , differently from the mono-Ir^III complexes.

Keywords: iridium; organometallics; phosphorescence; porphyrinoid; subporphyrin.