| New and previously reported di-, ter-, and penta-valent technetium complexes having the formulae (TcD(,2)X(,2))Y, (TcD(,2)X(,2)), (TcD(,2)Cl(,4))Y, and (TcD(,2)O(,2))TcO(,4), where D is o-phenylenebis(dimethylarsine) (diars), 1,2-bis(diphenylarsino)ethane (dae), or 1,2-bis(dimethylphosphino)ethane (dmpe), X is F, Cl, Br, or I, and Y is F('-), Cl('-), Br('-), I(,3)('-), ClO(,4)('-), PF(,6)('-), or CF(,3)SO(,3)('-), have been synthesized. The complexes were characterized by elemental analysis, optical and vibrational spectroscopy, magnetic susceptibility, and single-crystal X-ray analysis. The chemical and spectral data for the six-coordinate halo complexes are consistent with a trans octahedral coordination geometry, being typical for (MD(,2)X(,2))('+,0) complexes. The radiochlorine exchange reaction of trans-(Tc(diars)(,2)Cl(,2))ClO(,4) was investigated and the rate was found to be first-ordered in (Tc(diars)(,2)Cl(,2))ClO(,4) concentration and zero-ordered in chloride ion concentration. The reported (Tc(diars)(,2)Cl(,4))('+) complex is the only known eight-coordinate technetium complex, and the (Tc-(diars)(,2)O(,2))TcO(,4) complex is the first reported trans dioxo technetium-arsine complex.;Twenty-six cationic Tc-99m complexes, based upon seven different ligand series, have been synthesized under "no carrier added" conditions and qualitatively evaluated as myocardial imaging agents in a dog model. Of these complexes, the seven halogen derivatives of the diars and dmpe series successfully concentrate in the myocardium. These Tc-99m diars and dmpe complexes are shown by thin-layer chromatography to be identical to the Tc-99 octahedral complexes of Tc(III) by classical chemical techniques. Tissue distribution studies in rats show a definite difference in the biodistributions of ('99m)Tc(diars)(,2)Cl(,2)('+) and ('99m)Tc(diars)(,2)Br(,2)('+), despite the similar size, shape, charge, and lipophilicity of these two complexes. A tissue distribution study in resting beagle dogs shows that the ('99m)Tc(diars)(,2)Br(,2)('+) complex accumulates in the normal myocardium about half as well as T1-201 (0.022 compared with 0.038 % dose/g). |
