SYNTHESIS, CHARACTERIZATION, AND REACTIVITY OF NOVEL ORGANOCHROMIUM(III) PORPHYRIN COMPLEXES

The preparations of the organometallic porphyrin complexes (TTP)CrR (TTP is the dianion of meso-tetra-p-tolylporphyrin; R is C6H5, C6H4tBu-p, or CH2SiMe3) are described. The new compounds were synthesized by metathesis of (TTP)CrCl with the corresponding organolithium or Grignard reagent and characterized by H-1 NMR and electronic spectroscopies. The reactivity of (TTP)CrR toward molecular oxygen in CDCl3 and CeD6 solutions was investigated. In the former solvent, the initially observed products were (TTP)Cr(O) and RD, while little or no reaction occurred in the latter solvent until BrCCl3 was added. These results suggest that the reaction commences upon coordination of dioxygen, followed by homolysis of the Cr-C sigma-bond with subsequent trapping of R. by solvent or BrCCl3, respectively. The reactive properties of (TTP)CrR with heat, light, acid, 12, and HgCl2 are also reported.