Synthesis and Characterization of Technetium and Rheniui\m Organohydrazide Complexes

Chapter 1. Group 7 organohydrazide complexes can be classified into eight monohapto structural types on the basis of X-ray structural data. Classification on this basis provides a way for uniform identification of the ligand structural types present in a complex and for uniform assignment of oxidation states of the metal. Chapter 2. The organohydrazide chelate complexes, M(III)(NNpy)(PPh 3)2C12 (1), (3) (M = Re, Tc), have been synthesized using the organohydrazine, 2-hydrazinopyridine. The chelated organohydrazide is a diazenido(l-) ligand that forms a five-membered ring with the metal center. An X-ray structural analysis of (1) indicates that there is a delocalized et-system formed by the chelate ring. These octahedral, d4 metal complexes have diamagnetic 1H NMR spectra. Complex (1), C4 1.50H34C12N300.5P2Re, crystallizes in the triclinic space group P1 with a = 10.5549(7) A, b = 12.2699(8) A, c = 16.8206(12) A, oc = 105.9050(10)o, 3 = 95.8930(10) ° , y = 111.0100(10)0, V = 1906.1(2)A 3 , Z= 2, and R = 0.0650 based on 5268 unique reflections. The FABMS+{pnitrobenzylalcohol } of (3) reveals a parent ion peak at 799.2 m/z. The complex [Re(HNNpy)(NNpy)(PMe2Ph)2C1]+[Cl] (2) contains a chelated, neutral organodiazene ligand and a linear, diazenido(1-) ligand. The X-ray structural analysis of (2), C26H30 C12N6P2Re, indicates a delocalized it-system formed by the chelate ring. The 1H NMR spectrum of (2) is not paramagnetically shifted. Complex (2) crystallizes in the orthorhombic space group Pna21 with a = 17.383(4) A, b = 13.967(3) A, c = 12.002(2) A, V = 2913.9(10) A 3 , Z = 4, and R = 0.0384 based on 3083 unique reflections. Complex (4), [Tc(HNNpy)(NNpy)(PPh 3)Cl] [Cl]-, also contains a monodentate, linear diazenido(l-) ligand and a chelated neutral organodiazene ligand. The 1H NMR spectrum of (4) is not paramagnetically shifted. Chapter 3. Organohydrazide chelate complexes of rhenium and technium have been synthesized using 2-hydrazino-4(trifluoromethyl)pyrimidine. The complexes all contain a chelating organohydrazide that forms a five-member ring with the metal center. The chelate ring forms a delocalized nr-system and contributes to the unique electronic characteristics of the d4, octahedral complexes (1), (2) and (3), which all have 1H NMR spectra characteristic of diamagnetic complexes. An X-ray structural analysis of (1), Tc(III)(NNC 4H2N2CF 3)(PPh 3)2C12, was obtained. Complex (1), C41H32Cl2F3N4P2Tc, crystallizes in the triclinic space group Plwith a = 11.9193(3) A, b = 12.7026(3) A, c = 14.1335(3) A, a = 109.9320(10) °, 3 = 94.1250(10)", = 105.0490(10)", V= 1912.14(8) A3, Z = 2 and R = 0.0737 based on 3528 unique reflections. The complex Re(Il)(NNC4H2N 2CF3)(PPh 3)2C12 (2) was prepared and characterized. Both (1) and (2) contain a uninegative, chelating diazenido ligand. An X-ray structural analysis of (3), Re(fII)(NNC 4H 2N2CF3)(HNNC4H 2N2CF 3)(PPh3)C12 was obtained. Complex (3), C28H20Cl2F6NsPRe, crystallizes in the monoclinic space group P21/c with a = 10.1292(2) A, b = 14.92310(10) A, c = 20.6924(4) A, a= y= 90%, 3 = 92.4560(10)*, V= 312497(9) A3, Z= 4 and R = 0.0807 based on 4472 unique reflections. Complex (3) contains a monodentate, uninegative diazenido ligand and a chelating, oa-nitrogen protonated, neutral diazene ligand. A Tc(I) complex (4), Tc(NO)(NNC 4H2N2CF3)(PPh3)2C1, was prepared and characterized. Complex (4) contains a uninegative, chelating diazenido ligand. Chapter 4. Rhenium(I) chelated cis-amide complexes have been synthesized from Re(CO) 3(PPh3)2C1. These complexes are of the form Re(CO) 2(PPh3)2(N-C(=O)-R) and contain a five-membered chelate ring. Complex (1), C44H40NO 3P2Re, crystallizes in the triclinic space group Plwith a = 12.102(2) A, b = 13.981(2) A, c = 14.011(2) AO, a = 97.57(3)", 3 = 112.51(3), y = 94.71(3)*, V = 2148(2) A3, Z = 2, R = 0.067, and Rw = 0.073. Chapter 5. Reactions using 2-hydrazinoimidizoline and perrhenate and pertechnetate in the presence of triphenylphosphine were conducted. The organohydrazide complex formed is paramagentic possibly due to the fact that the imidizoline ring is not aromatic. The technetium product decomposes to Tc(N)(PPh3)2C12 in the solid state in a period of days. In addition, 2hydrazinoimidizoline was reacted with Tc(NO)(NCMe)(PPh 3)2CI2. Thesis Supervisor: Alan Davison Title: Professor of Chemistry