Synthesis, Characterization And Biodistribution Of New 99mTc-nitrido And 99mTc-oxo Complexes Of Unsaturated Tetradentate (N₂O₂, N₂S₂, N₂SO) Ligands

This work is an attempt to find new brain and heart imaging agents labeled with Tc-99m.Thirteen ligands were synthesized. They were divided into four types: A: Schhiff-Bases(N₂O₂) B: Thiophenemethylamines (N₂S₂) C: Dithiosemicarbazones(N₂S_a)D: Thiophenemethylamine-Schiff bases (N₂SO). The Tc-nitrido complexes were prepared from these ligands and [TcNCl₄]- by substitution reaction, and then labeled according to the Baldas method. We also prepared Tc-oxo complexes which were formed by three methods: (1) direct labeling, using SnCl₂ as reducing agent; (2) indirect labeling, using citric acid as exchanging agent; (3) substition reaction.There are two ionizable atoms (H) attached to the ligands. After complexing with TcN²⁺, these ligands lose these two hydrogen atoms and form neutral lipid-soluble complexes. On the other hand, Tc-oxo complexes were cationic. It was anticipated that it was possible for the former class of complexes to penetrate the B.B.B. and for the second class of complexes to display myocardial retention activity.Radiochemical analysis included the determination of labeling yields, partition coefficients, charge and the proteine binding.