The synthesis and characterization of technetium and rhenium hydrazinopyrimidine chelate complexes

Organohydrazide chelate complexes of rhenium and technetium, which are defined as complexes containing a; metal-nitrogen-nitrogen linkage, have been synthesized using 2-hydrazino-4-(trifluoromethyl)pyrimidine. The complexes all contain a chelating organohydrazide that farms a five-membered ring with the metal center. The chelate ring forms a delocalized pi system and contributes to the unique electronic characteristics of these d(4), octahedral complexes, which all have H-1 NMR spectra characteristic of diamagnetic complexes. An X-ray structural analysis of Tc-III(NNC4H2N2CF3)(PPh3)(2)Cl-2 1 was obtained. Complex 1, C41H32Cl2F3N4P2Tc, crystallizes in the triclinic space group P (1) over bar with a = 11.9193(3), b = 12.7026(3), c = 14.1335(3) Angstrom, alpha = 109.9320(10), beta = 94.1250(10), gamma = 105.0490(10)degrees, U = 1912.14(8) Angstrom(3), Z = 2 and R = 0.0737 based on 3528 unique reflections. The complex Re-III(NNC4H2N2CF3)(PPh3)(2)Cl-2 2 was prepared and characterized. Both 1 and 2 contain a uninegative, chelating diazenido ligand. An X-ray structural analysis of Re-III(NNC4H2N2CF3)(HNNC4H2N2CF3)(PPh3)Cl-2 3 was obtained. Complex 3, C28H20Cl2F6N8PRe, crystallizes in the monoclinic space group P2(1)/c with a = 10.1292(2), b = 14.92310(10), c = 20.6924(4) Angstrom, beta = 32.4560(10)degrees, U = 3124.97(9) Angstrom(3), Z = 4 and R = 0.0807 based on 4472 unique reflections. Complex 3 contains a monodentate, uninegative diazenido ligand and a chelating, a-nitrogen protonated, neutral diazene ligand.