Nitric Oxide Photorelease from Ruthenium Salen Complexes in Aqueous and Organic Solutions

The complexes [Ru(salen)(NO)Cl] and [Ru(salen)(NO)(H2O)]+ were shown to release the nitrosyl ligand as nitric
oxide upon exposure to visible light in organic and aqueous solutions respectively, by means of UV−visible, EPR,
and FTIR spectroscopies. The former was prepared by a new synthetic route and had its structure determined by
single-crystal X-ray diffraction. A crystal of the dichloromethane solvate is orthorhombic, space group Fdd2 (No.
43) and formula C16H14ClN3O3Ru·CH2Cl2, with Z = 16 and cell parameters a = 25.489(4), b = 33.435(4), and
c = 9.3716(9) Å. The electronic absorption spectra of the complexes were calculated using the INDO/S method.
The water-soluble complex is a potential drug for antitumoral phototreatment.