Novel bis(diethylenetriamine)thallium(III) complex. Synthesis and characterization in pyridine solution and in solid

A new complex of thallium(III) with the nitrogen donor ligand diethylenetriamine (dien) has been prepared and characterized by multinuclear NMR (1H, 13C, 205Tl), infrared and Raman spectroscopy, and X-ray diffraction. In solution, the symmetric s-facial isomer of [Tl(dien)2]3+ is formed. This is a fluxional molecule even at low temperature (235 K); therefore, the different rotamers cannot be observed separately. A complete characterization of the complex is given from its non-trivial NMR spectra. The crystal structure of [Tl(dien)2](ClO4)3·H2O shows u-facial geometry, where the coordination environment around thallium can be described as a distorted trigonal prism.