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.

Date of Award	1972
Original language	English