Synthesis of arylthallium complexes using organomercury compounds. Crystal and molecular structures of [NMe4][Tl(C6H4NNPh-2)Cl3] and [Tl(C6H4CH2-NMe2-2)Cl2]

Abstract

The reaction of [Hg(C₆H₄NNPh-2)₂] or [Hg(C₆H₄CH₂NMe₂-2)2] with [NMe₄]₂[TlCl₅](1:2) affords [NMe₄][Tl(C₆H₄NNPh-2)Cl₂] or [NMe₄][Tl(C₆H₄CH₂NMe₂-2)Cl₃] respectively. These two anionic complexes react with NaClO₄ to give the neutral compounds [Tl(C₆H₄NNPh-2)Cl₂] and [Tl(C₆H₄CH₂NMe₂-2)Cl₂]. The crystal structure of [NMe₄][Tl(C₆H₄NNPh-2)Cl₃] shows a distorted trigonal bipyramidal geometry around the thallium atom, if the rather weak interaction between thallium and the farther N atom [2.786(8)Å] is included. The nitrogen and carbon atoms occupy axial and equatorial sites, respectively, and a five-membered TlC₂N₂ ring is observed. The Tl–Cl distances are normal, with Tl–Cl_ax[2.575(3)Å] longer than Tl–Cl_eq[2.500(4) and 2.427(3)Å]. The crystal structure of [Tl(C₆H₄CH₂NMe₂-2)Cl₂] consists of a dimer with two asymmetric chlorine bridges [Tl–Cl 2.530(4) and 2.937(3)Å]. The chelating ligand again gives rise to a five-membered ring, here TlC₃N. Each thallium atom has a distorted trigonal bipyramidal environment in which the axial positions are occupied by the nitrogen atom of the aryl ligand [Tl–N 2.513(8)Å] and the weakly bonded bridging chlorine. The equatorial sites are occupied by the carbon atom of the aryl ligand [Tl–C 2.127(10)Å], the other bridging chlorine, and a terminal chlorine [Tl–Cl 2.392(3)Å].