Preparation of ,-[Pt(py)(N)(OH)] via Photoinduced Reactivity of [Pt(NO)] Anion.

The photoinduced reaction of [Pt(NO)] with pyridine or its derivatives (L) was found to result in the formation of PtL salts in high yield. This transformation was successfully probed for methyl- and carboxyethyl-substituted pyridines, and the corresponding PtL salts were isolated and fully characterized using single-crystal X-ray diffraction (SCXRD). Anation of the [Pt(py)] cationic complex with N was studied by H NMR spectroscopy in aqueous and water/dimethyl sulfoxide solutions of Pt(py). A mixture of cis- and trans-[Pt(py)(N)] complexes was determined as the final product of this interaction with the domination of the trans-isomer (cis to trans ratio is about 1:8) due to its preferable formation from the transient [Pt(py)(N)] cationic complex. The difference observed for the experimentally determined activation parameters of trans- and cis-paths of anation was supported by DFT calculations. Finally, the new three-stage Ag-free synthetic procedure for the preparation of the trans,trans-[Pt(py)(N)(OH)] prodrug (potential agent for the photodynamic anticancer therapy) was found using (i) light-induced formation of Pt(py) from (BuN)[Pt(NO)] followed by (ii) anation of [Pt(py)] with azide and (iii) accomplished by oxidation of the resulting mixture of cis- and trans-[Pt(py)(N)] with HO. Efficient separation of cis,trans-[Pt(py)(OH)(N)] and trans,trans-[Pt(py)(N)(OH)] produced at the last stage was achieved by simple recrystallization from water.