Ethanol coordinated zinc trimethoxyphenylporphyrin: Structure, theoretical studies and formation of isoporphyrin

Oxo-Free Hydrocarbon Oxidation by an Iron(III)-Isoporphyrin Complex

“…2 demonstrated spectral similarities to previously reported isoporphyrin complexes, in particular the appearance of near-IR features (λ = 810 and 902 nm) that are often associated with isoporphyrins. , Fujii et al and later Karlin et al reported the formation of Fe III meso -chloro-isoporphyrin complexes by the treatment of Fe IV O-porphyrin-π-cation radicals with trifluoroacetic acid and excess Cl – . As observed for 2 , a decrease in intensity and splitting of the Soret band was also observed in the meso -chloro-isophorphyrin derivative of [Fe III (Cl)­(TPFP)]. ,, We therefore postulated that the reaction of 1 with (dichloroiodo)­benzene yielded the meso -chloro-isophorphyrin complex, [Fe III (Cl) 2 (T­(OMe)­PP-Cl)], defined as 2 .…”

“…X-band electron paramagnetic resonance (EPR) spectroscopy analysis of frozen solutions of 1 and 2 (12 mM, DCM, 77 K) showed an axial signal consistent with a high-spin Fe III complex for both species (Figure S3). , The axial signal together with the average g -values ( g av = 4.58 ( 1 ) and 4.54 ( 2 )) are consistent with the unpaired spin-density lying at an S = 5/2 d 5 Fe III core in a square-pyramidal or octahedral coordination sphere. , The measured g -values for 2 ( g ⊥ = 5.83, g ∥ = 1.96) displayed only a marginal difference in comparison to 1 ( g ⊥ = 5.90, g ∥ = 1.94), demonstrating no change in oxidation state and very little change in the coordination environment at the metal. By double integration of the signal obtained for 2 and comparison against 1 , the EPR-determined yield indicated a quantitative conversion of 1 to 2 (see Supporting Information for details).…”

“…[M IV (X) 2 (por)] (M = transition metal, X = halogen, por = porphyrinoid ligand) like [Mn­(X) 2 (TMP)] (X = Cl, F), , [M­(X) 2 (TPP)] (M = Ru, Os; X = Cl, Br, I; TPP 2– = tetraphenylporphyrinyl), and [Pt­(Cl) 2 (TPP)] are synthetically accessible; however, their ability to halogenate hydrocarbons is unproven. Treatment of a metalloporphyrin with an oxidant can lead to oxidation of the ligand backbone, rather than on the metal site, and formation of isoporphyrins, which show characteristic spectroscopic features and reactivity . Of relevance to the current study, Fujii et al and later Karlin et al reported the formation of Fe­(III) meso -chloro-isoporphyrin complexes by treatment of Fe­(IV)-oxo porphyrin π-cation radicals with trifluoroacetic acid and excess tetra-butylammonium chloride under liberation of water. , It has been demonstrated that the iron­(III) meso -chloro-isoporphyrin was able to perform chlorination on C sp 2 –H bonds via electrophilic aromatic substitution or electrophilic addition.…”

Quest for Zinc Methoxyisoporphyrin Molecules: Experimental and Theoretical Studies

“…The decreased fluorescence intensity of isoporphyrin with respect to parent porphyrin is due to loss of aromaticity. The quantum yield of a free‐base porphyrin, the corresponding zinc porphyrin, and isoporphyrin complex has been reported earlier [28–29] . The free base porphyrin showed the highest quantum yield (Φ F =0.48), while the corresponding zinc isoporphyrin gave the lowest quantum yield (Φ F =0.01).…”