Halogeno and isothiocyanato complexes with phosphine, phosphonite or arsine ligands

1 Halogeno and isothiocyanato complexes with phosphine, phosphonite or arsine ligands 

The tetrabromotcchnclate(Il) anion, [TcBr4] was reported to be obtained by reaction of [TcNBr4 with 2,2 -dipyridyl in ethanol yielding m-[Tc NBr(bpy)2 2 TcBr4. Tc(II) is tetrahedrally coordinated by Br . The Br-Tc-Br angles vary between 106.1 and 112.1 The mean Tc-Br bond length is 2.401(4) A [280,281]. 

A structurally analogous compound is the isothiocyanato complex trans-[Tc (NCS)2(dppe)2] which was synthesized by the action of excess LiSCN on [Tc X2(dppe)2] (X = Cl,Br) in DMF or ethanol at 80-100 (397]. The rose-colored 

Similarly, chloro-dimcthylphenylphosphine complexes of Tc(II) and Tc(I) were obtained when TcCl4(PMe2Ph)3] was reduced electrochemically in acetonitrile at platinum electrodes [405], 

The neutral diarsine complexes Tc (diars)2X2]° (X=Cl,Br,I) are long known and arc obtained by reducing the Tc(IlI) compounds [Tc(diars)2X2]X with H PO . The yellow to brown non-electrolytes are slightly soluble in nitrobenzene and nitro-methane. The magnetic moment of the complexes range from 1.9 to 2.1 M.B. at 20 °C. TTiey are isostructural with the analogous complexes of Re(ll) 79.412.  

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