Complexes nitrido

Tetrachloronitridotcchnetate(VI) may also be obtained by reaction of [ButaN] [TcOCla], dissolved in dichloromethanc, with a solution of NCI3 in carbon tetrachloride  

The inlcrconversion of monomeric, p-oxo. and di(//-oxo) dimeric nitridotechne-tium(Vl) species in aqueous solution was studied by HPR and VIS/IJV spectrophotometry. The position of the equilibrium and the rates of interconversion of the species depend on the acidity and the coordination ability of the medium. High acidity (cone. HCl) favors the monomeric form [TcNCUlOIU)] . readily established by EPR spectroscopy. The dimeric species can not be seen by HPR. The di(/i-oxo)structure was confirmed by single crystal X-rav structure determination of [AsPh4]2l TcNCl2)2 0 O)2f (Fig. 12.7.A) [64.  

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The conversion of coordinated NSCI into a nitrido ligand provides a useful synthesis of transition-metal nitrides. For example, treatment of ReCl4(NSCl)(POCl3) with triphenylphosphine generates the nitrido complex ReNClaCPPhsla. "... 

Figure 1.75 The structure of the dimeric nitrido complex [Ru2NC18(H20)2]3. ...

The Fe(lll)-azide-precursor and the photolysed product were characterized by NIS spectroscopy coupled to detailed DFT calculations [63]. The result of the study provides additional evidence in favor of a low-spin 5=1/2 ground state of the Fe(V)-nitrido complex. Here we show how first-principles calculations assist in quantitative analysis of experimental NIS data for the Fe(lll)-azide complex. 

The results obtained to date are considerable and show that the chemistry of the TcN group may well be the most varied and interesting of the transition metal nitrido complexes [1,9,10]. The aim of this chapter is to provide a fairly comprehensive review of the literature up to the latter part of 1994. Additional data may be found in two conference volumes [11,12] and a recent review of Tc coordination chemistry [4]. For macroscopic studies with the long-lived "Tc (ti/2 = 2.11 x 10s years) the "Tc radionuclide is denoted simply as Tc. No carrier added studies and radiopharmaceutical applications utilizing the shortlived "mTc radionuclide (ti/2 = 6.01 hours) are denoted as "mTc. 

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