BIS-(8-OXO QUINOLINE)DIORGANO TELLURIUM(IV) COMPOUNDS - STRUCTURAL AND SPECTROSCOPIC STUDIES

Three new compounds of the type R2Te(OR')2 are reported in which R' be ars a potentially co-ordinating group: bis-(8-hydroxo quinoline)dimeth yltellurium (I) bis-(8-oxo-2-methyl quinoline)dimethyltellurium (II), and bis-(8-oxo-quinoline) di-(p-tolyl)tellurium (III). The crystal str uctures of II and III have been determined. The primary geometry aroun d tellurium in both cases can be described as PSI-trigonal bipyramidal but long Te ... N contacts in the range 2.840(6)-2.899(4) angstrom wh ich lie well within the van der Waals distance imply extension of the co-ordination sphere. Variable temperature multi-nuclear (H-1, C-13, T e-125) studies of the compounds I, II, and III in solution indicate th e presence of a single species over the range 216-343 K. The data do n ot distinguish between the presence of a single 14-Te-6 pertellurane s een in the crystallographic studies, or that of such a species in equi librium, rapid on the H-1 and Te-125 timescales, with the 10-Te-4 tell urane.