Rhodium(I) and rhodium(III) complexes of hybrid organo-tellurium ligands, 1-(NMe2)-2-(TeAr)-4-MeC6H3 and HN(C2H4TeAr)2, ar=4-MeOC6H4 or 4-EtOC6H4

Abstract

The 1-(NMe2)-2-(TeAr)-4-MeC6H3 (1) and HN(C2H4 TeAr)2 (2) ligand react with RhI and RhIII to yield diamagnetic complexes of [RhCl(L)]2 and [RhCl3(L)n] stoichiometry [L=(1), n=2;L=(2), n=1]. The complexes behave as non-electrolytes in nitrobenzene. The ν(Te−C), ν(N−C) and ν(N−H) [with (2) only] bands in the i.r. spectra of (1) and (2) undergo red shift (ca. 5–25, 35–60, and 290–300 cm−1 respectively) upon complexation with RhI and RhIII, suggesting involvement of all N and Te donor sites in the ligation. The1H n.m.r spectrum of [RhCl3·(1)2] exhibits NMe2 and aryl signals deshielded byca. 1 and 0.5 ppm respectively which supports the bidentate ligation of (1) with RhIII. Molecular weight measurements suggest that the RhI complexes are dimers whereas the RhIII complexes of (1) are monomers. Rhodium(III) complexes of (2) exhibit intermediate molecular weights.