A Study of some Complexes of Thallium and Tellurium

Abstract

Complexes of the type TIX.L (where L = bipy, phen, dipyam etc. and X=Cl and Br) were prepared together with some new complexes with the terdentate ligand tri-(2-pyridyl)amine. When the above complexes were recrystallized from dimenthyl formamide (DMF) a new series of complexes with co-ordinate DMF were obtained. The structure of TIX, (tripyam) was obtained with the help of 1H nuclear magnetic resonance, diffuse reflectance spectroscopy and infra-red spectroscopy. The structure was "octahedral" with C3, symmetry. The structure of the complex TIX, (tripyam) DMF was also deduced, When DMF was co-ordinated into the octahedral sphere, the terdentate tri(2-pyridyl)amine opened to become a bidentate base. The infra-red and 1H n.m.r. spectra ere produced in evidence for the co-ordinated DMF and also for the bidentate tri-(2- pyridy] )amine base. The structure of the TIX3(chelate) were also obtained with the help of far-infra and Raman vibrational spectroscopy and of a chemical approach. The evidence suggested polymeric structures for the complexes. The finding is renewed in the light of recent X-ray studies with TI (phen)C1, and the difficulties of interpreting vibrational spectroscopic data for the complexes of heavy metals is stressed. The thallium (1) complexes with bipy,phen, thiovrea and substituted thioureas were prepared. The structure of the thallium {1} complexes with the nitrogen donor ligands is believed to be relatively undistorted. Some new complexes of thallium (I) with substituted thiourea were obtained and the possible assignments are suggested. The organotellurium compounds with the formula R,Te and Rolex, (where R = phenyl, o-tolyl, p-tolyl ,p-methoxyphenyl, p-ethoxypheny] and X = Cl, Br and I) were prepared. Some new compounds such as the di (perf luoropheny1) tellurium dihalides and dibenzyltellurium dihalides were prepared. The far infra-red and Raman spectra of the above compounds were obtained and discussed in detail. The low frequency infra-red and Raman spectra were assigned for the diaryltellurium dihalides. The spectra of the above compounds suggested that the basic ‘y- trigonal bipyramidal structure is common to all compounds, Dibenzyltellurium dihalides were prepared to study 1H n.m.r. spectra but no coupling of the methylene group with 125 Te was seen. Attempts were made to prepare telluroylids. Some use of diaryltelluride were investigated with the possible catalytic use of the diaryl telluride. The possible use of organotellurium compounds as dehalogenating agents or dehalogenodimerisation agents was investigated but it was found that the compounds offer no particular advantage over other reagents.