Functionalized sandwich complexes of transition metals are used as precursors for numerous reactions with applications in different fields, including medicinal inorganic chemistry and catalysis^1-3. Re(I) and ^99(m)Tc(I) bis arene complexes represent a new promising route to low valent, nonpolar, and inert compounds¹  and could represent building blocks for the development of new potential pharmaceuticals and catalyst. The synthesis of technetium and rhenium bis arene complexes was first stablished by Fischer and Hafner in the 1950s and 1960s using AlCl₃ as an activation agent. More recently, some modification to the synthesis have been done by Kudinov³ and in our group¹ but still AlCl₃ is needed in the reaction. The high reactivity of AlCl₃ limits the synthesis of Re(I) and ^99(m)Tc(I) bis arene complexes to only alkyl arene substituents. Here, we present the first direct synthesis of nitrogen functionalized bis arene complexes of rhenium(I). Different ligands presenting sp³ and sp² nitrogen were evaluated. Whereas the presence of sp² nitrogen in the ligand hampers the formation of sandwich complexes, promising results have been obtained for ligands containing sp³ nitrogen. The synthesis of [^99(m)Tc(N,N- dimethylaniline)₂]⁺ analogue was performed following Benz procedure¹  as a proof of applicability in technetium chemistry. Optimization of reaction conditions and purification procedures, as well as the search for other suitable ligands are currently on going.

[1] M. Benz, H. Braband, P. Schmutz, J. Halter, R. Alberto, Chem. Sci., 2015, 6, 165-169
[2] G. Pampaloni, Coord. Chem. Rev., 2010, 254, 402-419.
[3] E. A. Trifonova, D. S. Perekalin, K. A. Lyssenko, A. R, Kudinov, J. Organomet.Chem., 2013, 727, 60-63.