Crystal structure, electrochemical and photochemical studies of the trans-[Fe(cyclam)(NO)Cl]Cl2 complex (cyclam = 1,4,8,11-tetraazacyclotetradecane)

The trans-[Fe(cyclam)(NO)Cl]Cl2 complex was synthesized by the reaction of cis-[Fe(cyclam)Cl2]Cl with NO gas. The X-ray structure of the complex showed that the [Fe–NO] moiety is linear, consistent with the NO+ character of the nitric oxide ligand. This suggestion was reinforced by the IR data, which showed the νNO at 1888 cm−1. The cyclic voltammogram of the trans-[Fe(cyclam)(NO)Cl]2+ complex presented three electrochemical processes at −0.70, 0.08 and 0.40 V versus Ag/AgCl. The first and last redox processes are centered at the NO ligand, whereas the second is characteristic of the generated aqua species, trans-[Fe(cyclam)Cl(H2O)]2+. Upon irradiation at 330 nm, pH 3.4, the title complex releases the NO moiety with the concomitant generation of the trans-[Fe(cyclam)(H2O)Cl]+ complex as suggested by electronic and IR spectroscopy as well as by cyclic voltammetry technique.

The cyclic voltammogram of the trans-[Fe(cyclam)(NO)Cl]2+ complex showed three electrochemical processes at −0.70, 0.08 and 0.40 V versus Ag/AgCl. The first and last redox processes are centered at the NO ligand, whereas the second is characteristic of the residual aqua species, trans-[Fe(cyclam)Cl(H2O)]2+.Figure optionsDownload as PowerPoint slide