Preparation, characterization and organ distribution of the oxochloro-BIS-(1,10-phenanthroline)technetium (V) cation

[TcOCl(phen)2]Cl2 was prepared by controlled potential cathodic reduction or dithionite reduction of TcO4 in aqueous alcoholic solution containing 1,10-phenanthroline(phen) monohydrate. The compound was also obtained by ligand exchange reaction of [TcOCl4] with phen-H2O in methanol. The strong IR absorption at 895 cm−1 was attributed to the Tc = O stretching vibration. The 1H NMR spectrum displayed 16 distinct resonances which were assigned by HH-COSY-experiments to the non-equivalent aromatic protons of the two phen ligands. The maximum uptake of [99mTcOCl(phen)2]2+ of 4.2% dose/g heart in mice, 1 min p.i., was low, probably reflecting the dipositive charge and the high hydrophilicity of the complex.