122489-69-4Relevant academic research and scientific papers
Synthesis, spectroscopy, and structural characterization of five-coordinate, bis(aryldiazenido)technetium complexes and their protonation reactions. X-ray structure of [TcCl(PPh3)2(NNC6H4Br)2]
Nicholson, Terrence,De Vries, Nadine,Davison, Alan,Jones, Alun G.
, p. 3813 - 3819 (2008/10/08)
The reaction of [TcCl4(PPh3)2] with arylhydrazines in methanol yields [TcCl(PPh3)2(NNPh)2] (1). Complex 1 displays trigonal-bipyramidal geometry with phosphine ligands occupying axial sites. The technetium-aryldiazenido moieties are nearly equivalent, with Tc-N-N bond angles of 166.2 (6) and 170.7 (7)° and multiple bonding throughout. The chloride ligand occupies the remaining equatorial coordination site. The addition of HCl(g) to complex 1 in methanol gives the neutral, six-coordinate hydrazido(2-) complex [TcCl2(PPh3)2(NNPh)(NNHPh)]. The reaction of complex 1 with HBr(g) gives the doubly protonated, cationic species [TcBr2(PPh3)2(NNPh)(NHNHPh)](Br). The 99Tc NMR spectra for these species are presented, which suggest that the metals exhibit considerable Tc(V) character and that the formal oxidation states of -1 and +1 are not accurate descriptions of the electron density on the technetium. The 1H NMR, mass, and electronic spectroscopic data are also presented for the various species, along with the crystal structure of the five-coordinate bis(aryldiazenido) precursor. Crystal data for C48H38N4P2ClBr2Tc: monoclinic space group P21/n, a = 12.174 (2) A?, b = 19.008 (3) A?, c = 20.162 (3) A?, β= 106.39 (1)°, V = 4476 (1) A?3 to give Z = 4. Structure solution and refinement based on 4135 reflections converged at R = 0.053 and Rw = 0.062.
