Tc(NX)Y3(Me2PhP)2 complexes (X = O or S; Y = Cl or Br). Preparation, characterization and EPR studies

EPR Spectroscopy on Technetium Compounds

“…Deviations can be observed with ligands which show distinct bonding behaviour like F", NCS" or CN" [10,13,14], Nevertheless, the experimental EPR parameters are a valuable tool to charac- terize instable intermediates in ligand exchange reactions [9][10][11][12][13][14], Direct conclusions on the composition of the equatorial coordination sphere (the ligands in trans-position have been found to have only a very small influence on the EPR parameters [15,16]) can be drawn from resolved superhyperfme interactions due to hgand nuclei. This has been observed for phosphorus (nuclear spin ^'P: / = 1/2) and arsenic (^^As: 1=3/ 2) containing ligands [17][18][19] and Br" / = 3/2) [20], Well-resolved superhyperfme triplets have been obtained in the frozen Solution EPR spectrum of [Tc(NO)Cl3(Me2PhP)2] giving evidence for an equatorial coordination of both phosphine Hgands [21], The spectrum of the corresponding thionitrosyl complex, however, showed only a doublet Splitting of the ^'Tc hyperfme structure lines [17]. An X-ray structure determination confirmed the asumption that only one phosphine ligand is arranged equatorially [22], In contrast to the axially-symmetric spectra of the [Tc(NY)X4]-and [TcNXJ" complexes (X = Cl, Br, F, Nj; Y = O, S), EPR spectra of trigonal-prismatic or trigonally distorted octahedral complexes show no or only badly resolved ®®Tc hyperfme couplings [23 -25].…”

[{TcI(NO)(LOMe)(PPh3)Cl}2Ag](PF6) and [TcII(NO)(LOMe)(PPh3)Cl](PF6): Two Unusual Technetium Complexes with a “Kläui‐type” Ligand

“…experimental spectrum, they can be estimated from line-width considerations to have values of approximately 25 • 10 À 4 cm À 1 for the parallel part and 20 • 10 ]. [26][27][28] Unlike the spectra with monodentate phosphines, which have almost isotropic g tensors, [25,26] the spectrum of 3 shows a considerable anisotropy. This is most probably a consequence of the chelate formation and has been observed before for Tc(II) complexes with P,N-chelating ligands.…”

Nitrosyltechnetium(I) Complexes with 2‐(Diphenylphosphanyl)aniline

“…Most of the compounds were prepared by ligand exchange reactions starting from (NBu 4 )[Tc(NO)Cl 4 (MeOH)]. Other approaches to technetium nitrosyls are reactions of common starting materials such as [TcO X 4 ] – , [Tc X 6 ] 2– ( X = Cl, Br), TcO 2 , or even TcO 4 – with NO gas or hydroxylamine hydrochloride . Other nitrosylation agents for technetium compounds are HNO 3 , NO 2 – , NO + salts or acetohydroxamic acid …”