Ligand Exchange Triggered Photosensitizers – Bodipy‐Tagged NHC‐Metal Complexes for Conversion of ³O₂ to ¹O₂

Abstract

A new imidazolium salt 3•HI with 8-Bodipy as one N-aryl substituent was synthesized from 8-chloro-Bodipy and imidazole followed by alkylation with iPrI. NHC-metal complexes [CuCl( 3)], [AuCl(3)], [Pd(allyl)Cl(3)] and [MCl(cod)(3)] and [MCl(CO) 2 (3)] (M = Rh, Ir) were synthesized and the X-ray crystal structure of [IrCl(CO) 2 (3)] determined. The donation of NHC 3 was determined via IR (ν(CO) and cyclic voltammetry (Ir(I/II) redox potential). The photosensitizing properties of the complexes for the generation of 1 O 2 were quantified observing singlet oxygen quantum yield of up to Φ s.o. = 0.63. [IrCl(cod)(3)] displays poor Φ s.o. = 0.09, but, following a simple ligand exchange reaction of cod by two CO [IrCl(CO) 2 (3)], a pronounced increase to Φ s.o. = 0.63 is observed.

Phenylbenzothiazole-Based Platinum(II) and Diplatinum(II) and (III) Complexes with Pyrazolate Groups: Optical Properties and Photocatalysis

“…In recent years, photocatalytic oxidations have been successfully reported employing O 2 as an environmentally friendly oxidant and different organic photosensitizers, such as Rose Bengal, Rivoflavin, or Bodipy . In this area, the employment of metal phosphorescent complexes as photosensitizers is rather less developed; although recently, the efficiency of several Ir III , Ru II and Au I systems have been demonstrated . To increase the knowledge on these systems, we sought to explore the utility of complex 3a , which displayed strong oxygen sensitivity on its phosphorescent band, for the photocatalytic oxidation of sulfides using O 2 as a green oxidant.…”