Protoporphyrin 9 dimethyl ester

All the chemicals and reagents were purchased from commercial suppliers (Sigma-Aldrich, Alfa Aesar) and used without any further purification, unless otherwise stated. Mn- and Co-protoporphyrin IX, protoporphyrin IX dimethyl ester, and mesoporphyrin IX dimethyl ester were purchased from Frontier Scientific. EDA was purchased from Sigma-Aldrich as 87% solution in dichloromethane. All dry reactions were carried out under argon or nitrogen in oven-dried glassware with magnetic stirring using standard gas-tight syringes, cannulae and septa. ¹H and ¹³C NMR spectra were measured on Bruker DPX-400 (operating at 400 MHz for ¹H and 100 MHz for ¹³C) or Bruker DPX-500 (operating at 500 MHz for ¹H and 125 MHz for ¹³C). Tetramethylsilane (TMS) (0 ppm) or D₂O (4.6 ppm) or d₆-DMSO (2.50 ppm) served as the internal standard for ¹H NMR and CDCl₃ (77.0 ppm) or d₆-DMSO (39.51 ppm) was used as the internal standard for ¹³C NMR. Silica gel chromatography purifications were carried out using AMD Silica Gel 60 230–400 mesh. Thin Layer Chromatography (TLC) and preparative TLC were carried out using Merck Millipore TLC silica gel 60 F254 glass plates.

All reactions and manipulations of the iron(II) porphyrin derivatives were carried out under argon using a double-manifold vacuum line, Schlenkware, and cannula techniques. Dichloromethane, chloroform, methanol, and hexanes were distilled under argon over CaH₂, magnesium turnings, and sodium/benzophenone, respectively. The free bases, protoporphyrin IX dimethyl ester, deuteroporphyrin IX dimethyl ester, and mesoporphyrin IX dimethyl ester, were purchased from Frontier Scientific. Nitric oxide (Mittler Specialty Gases) was purified by fractional distillation through a trap containing 4A molecular sieves bathed in a dry-ice/ethanol slurry.²⁵