The reaction chemistry of a technetium(I) nitrosyl complex with potentially chelating organohydrazines:: the X-ray crystal structure of [TcCl2(NO)(HN=NC5H4N)(PPh3)]

The reaction of the nitrosyl complex [TcCl2(NO) (MeCN)) (PPh3)(2)] with 2-hydrazinopyridine dihydrochloride in refluxing MeOH gives the purple complex [TcCl2(NO) (HN = NC5H4N) (PPh3)(2)] (1) in which the neutral bidentate organodiazene ligand has replaced the acetonitrile and a phosphine ligand. The IR spectrum of 1 shows a very strong absorption at 1732 cm(-1) attributed to v(N = O). The FAB (+) mass spectrum of 1 displays the protonated parent ion at 570 m/z and the fragment generated by the loss of a chloride ligand from the parent ion at 533 m/z. The H-1 NMR spectrum of this diamagnetic complex displays the signal from the a-nitrogen-proton of the pyridyldiazene at 17.95 ppm as well as the aryl-protons. The X-ray crystal structure of this complex shows a distorted octahedral coordination geometry. The Tc-N bond length of 1.752(4) Angstrom is consistent with the multiple bonding expected for the linearly bonded nitrosyl ligand. The Tc-N-O bond angle is 175.1(4)degrees. The N-Tc-N bond angle of the chelated pyridyldiazene ligand is 73.1(2)degrees, which reflects the small bite angle imposed by the five-membered chelate ring of this ligand. The reaction of the nitrosyl complex [TcCl2(NO) (MeCN)) (PPh3)(2)] with 2-hydrazino-4-trifluoromethylpyrimidine in refluxing dichloromethane gives the neutral Tc(I) complex [TcCl(NO) (N = NC4H2N2-R) (PPh3)(2)] (2) in which the anionic bidentate organodiazenido ligand has replaced the acetonitrile and a chloride ligand. The IR spectrum of 2 shows a very strong absorption at 1717 cm(-1) attributed to v(N = O). The FAB (+) mass spectrum of 2 displays the parent ion at 866 m/z as well as the fragment generated by the loss of the diazenido ligand at 688 m/z. The peak associated with the loss of a phosphine ligand from the parent ion at 604 m/z is also evident. (C) 1998 Elsevier Science S.A. All rights reserved.