A. Marchi et al., NITRIDO-TECHNETIUM AND NITRIDO-RHENIUM COMPLEXES WITH CHELATING PHOSPHINES - SYNTHESIS, REACTIVITY AND CRYSTAL-STRUCTURES, Journal of the Chemical Society. Dalton transactions, (8), 1993, pp. 1281-1286
Nitrido-technetium(V) and -rhenium(V) complexes of general formula [MN
Cl2L] [M = Tc or Re; L = bis(diphenylphosphinoethyl)propylamine (L1),
1,8-bis(diphenylphosphino)-3,6-dioxaoctane (L2) or 1,1,1-tris(diphenyl
phosphinomethyl)ethane (L3)] have been synthesized and characterized.
They were prepared by the reduction of [Tc(VI)NCl4]- or by the replace
ment of the two triphenylphosphines of [MNCl2(PPh3)2] (M = Re or Tc) b
y bidentate or tripodal polyphosphine ligands L. Reaction of these com
plexes with an excess of potassium O-ethyl dithiocarbonate yields neut
ral dithiocarbonate compounds [MN(S2CO)L], while cationic and neutral
complexes [MN(S2CNEt2)L]+ and [MN(S2CNEt2)2] were obtained upon reacti
on with K(SCNEt2). The crystal structures of [TcNCl2L1] and [TcNCl2L2]
have been determined by X-ray crystallography; the complex [TcNClL1]
shows square-pyramidal coordination at technetium with the Tc atom dis
placed from the basal plane towards the N atom by 0.410 angstrom. An u
nusual trigonal-bipyramidal geometry is observed for [TcNCl2L2]. The T
c=N bond distances (1.60 angstrom) in both complexes are indicative of
a strong triple bond.