Organotellurium(II) and ‐(IV) Compounds with Picolinoylbis(thio­ureas): From Simple 1:1 Adducts to Multimetallic Aggregates

Reactions of 2,6‐dipicolinoylbis( N,N ‐diethylthiourea) (H 2 L Et ) with common tellurium(IV) starting materials such as PhTeBr 3 or TeBr 4 yield various tellurium(IV) and tellurium(II) compounds depending on the conditions applied. Equimolar amounts of H 2 L Et and PhTeBr 3 give the 1 : 1 complex [PhTe IV Br 3 (H 2 L Et )], while with an excess of H 2 L Et , the tellurium compound is partially reduced and a {PhTe II } + building block coordinates to both sulfur atoms of H 2 L Et under the formation of the ion pair [PhTe II (H 2 L Et )][PhTe IV Br 4 ]. Similar reactions between H 2 L Et and TeBr 4 give the neutral monomer [Te II Br 2 (H 2 L Et )] or the coordination polymer [Te II Br 2 (H 2 L Et )] ∞ . The latter compound is also formed with the assistance of Pb 2+ ions. While the lead ions do not appear in the isolated product, similar reactions with transition metal ions such as Ni 2+ , Mn 2+ , or Co 2+ result in the formation of heterobimetallic complexes, in which Te(II) building blocks are directed to the sulfur atoms of the deprotonated ligand {H 2 L Et 2 ‐S,S} 2− , while the transition metal ions occupy central coordination positions between two of the organic ligands using the pyridine nitrogen atom, carbonyl oxygen atom(s) and/or the nitrogen atoms of the thiourea units.