34035-97-7Relevant articles and documents
Temperature and isotope substitution effects on the structure and NMR properties of the pertechnetate ion in water
Cho, Herman,De Jong, Wibe A.,McNamara, Bruce K.,Rapko, Brian M.,Burgeson, Ingrid E.
, p. 11583 - 11588 (2004)
The uniquely well-resolved 99Tc NMR spectrum of the pertechnetate ion in liquid water poses a stringent test of the accuracy of ab initio calculations. The displacement of the 99Tc chemical shift as a function of temperature has been measured over the range 10-45 °C for the three isotopomers Tc(16O)4-, Tc( 16O)3(18O)-, and Tc( 16O)3(17O)- at natural oxygen isotope abundance levels, and in addition the temperature dependence of the Tc-O scalar coupling was determined for the Tc(16O)3( 17O)- isotopomer. Values for these parameters were computed using relativistic spin-orbit density functional theory with an unsolvated ion approximation and with treatments of the solvated ion based on the COnductor-like Screening MOdel (COSMO) approach. The temperature and isotope dependence of 99Tc NMR parameters inferred by these methods were in good quantitative agreement with experimental observations. The change in the Tc-O bond length associated with the changes in temperatures considered here was determined to be of the order of 10-4 A. Vibrational energies and Tc-O bond lengths derived from these models also compare favorably with previous experimental studies.
Synthesis and physical properties of hexakis(isothiocyanato)technetate(III) and -(IV) complexes. Structure of the [Tc(NCS)6]3- ion
Trop,Davison,Jones,Davis,Szalda,Lippard
, p. 1105 - 1110 (2008/10/08)
The reaction between ammonium thiocyanate and (NH4)2TcX6, X = Cl and Br, salts is shown to produce a mixture of red (λ 500 nm) [Tc(NCS)6]2- and air-sensitive yellow (λ 400 nm) [Tc(NCS)6]3- ions. These species were chromatographically separated and isolated as their ammonium, tetraphenylarsonium, or tetra-n-butylammonium salts. The technetium(IV) compound was also obtained through reduction of ammonium pertechnetate followed by treatment with ceric ion. Infrared, Raman, conductivity, and magnetic susceptibility data are reported for these complexes and shown to be consistent with octahedral structures. The detailed geometry of (n-Bu4N)3[Tc(NCS)6] was determined in a single-crystal X-ray diffraction study. The compound crystallizes in the cubic system, space group Pa3, with a = 24.444 (6) A? and Z = 8. The technetium atom is situated on a crystallographic threefold rotation axis. The Tc-N bond lengths are 2.04 (2) and 2.05 (2) A?, and the N-Tc-N angles range from 88.0 (6) to 92.1 (7)°, indicative of nearly perfect octahedral symmetry. The average Tc-N-C and N-C-S bond angles are 173 (2) and 177 (2)°, respectively. Voltammetric studies in acetonitrile show a reversible one-electron transfer between [Tc(NCS)6]3- and [Tc(NCS)6]2- with E1/2 of 0.18 V vs. SCE. Additional chemical redox reactions of these ions are reported.
