Computer-aided prediction of 125Te and 13C NMR chemical shifts of diorgano tellurides

Vicente P Emerenciano,Marcus T Scotti,Dennis G Diego,João V Comasseto,Marcelo J P Ferreira,Gilberto V Rodrigues

doi:10.1590/s0103-50532007000600012

Vicente P Emerenciano, Marcus T Scotti + Show 4 more

Open Access

https://doi.org/10.1590/s0103-50532007000600012

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Abstract

This work describes a method to predict the 125Te and 13C NMR chemical shifts of diorgano tellurides based in a three-dimensional approach. For that, a collection of 150 compounds were selected from the literature and had their geometry optimized using the PM3 semi-empirical method. From this data, the structures were coded by the FOCOS program which described the chemical environment for each atom present in the structure, totalizing 1411 focos for the substances. The method developed was tested with ten diorgano tellurides not inserted in the database showing a higher accuracy in the prediction of 125Te and 13C NMR chemical shifts than those predicted by the commercial program. The chemical shifts and the statistical parameters obtained in this work demonstrate that the method applied was able to predict successfully the 13C and 125Te NMR chemical shifts of the diorgano tellurides.

Highlights

In the last decades, organic tellurium compounds have been applied as ligands in transition metal chemistry,[1,2] polymerization catalysts,[3,4] anti-oxidant agents[5,6,7,8] and synthetic intermediates.[9,10,11,12] In view of this interest in the organic compounds of this element, analytical methods for their rapid identification are welcome
Considering the increasing importance of the organic tellurium compounds and the magnetic properties of 125Te commented above, in this work we developed a method to predict the 125Te and 13C Nuclear magnetic resonance (NMR) chemical shifts of diorganotellurides based in a three-dimensional approach
After the optimization process of the organo tellurides, their structures were coded by the FOCOS program,[30] which uses data derived from the optimized geometry and the reported 13C and 125Te NMR chemical shifts

Summary

Introduction

Organic tellurium compounds have been applied as ligands in transition metal chemistry,[1,2] polymerization catalysts,[3,4] anti-oxidant agents[5,6,7,8] and synthetic intermediates.[9,10,11,12] In view of this interest in the organic compounds of this element, analytical methods for their rapid identification are welcome. Nuclear magnetic resonance (NMR) spectroscopy in nowadays is the routine technique of choice for this end. There are eight naturally occurring isotopes of tellurium. Only 123Te and 125Te are active in NMR spectroscopy. The latter isotope is significantly more naturally abundant (7%) than the former one (1%). Considering the increasing importance of the organic tellurium compounds and the magnetic properties of 125Te commented above, in this work we developed a method to predict the 125Te and 13C NMR chemical shifts of diorganotellurides based in a three-dimensional approach

Theoretical approach

Atom codification

Results and Discussion

Conclusions