The Reactions of Tellurium Tetrahalides with Triphenylphosphine under Ambient Conditions

Abstract

The reactions of tellurium tetrahalides and triphenylphosphine in tetrahydrofuran have been carried out under ambient conditions and afford [(Ph(3)PO)(2)H](2)[Te(2)X(10)] [X = Cl (1), Br (2)] and [(Ph(3)PO)(3)(OH(3)])(2)[TeI(6)] (4). The X-ray structures of 1 and 2 show that they are isostructural and contain discrete [Te(2)X(10)](2-) anions exhibiting octahedral coordination around both tellurium atoms with one shared edge and [Ph(3)POH...OPPh(3)](+) cations that show strong hydrogen bonds (the O...O distances are 2.399 and 2.404 A for 1 and 2, respectively). The compound 4 is built up with discrete octahedral hexaiodotellurate anions and [(Ph(3)PO)(3)(OH(3))](+) cations. The reaction of TeBr(4) and PPh(3) also results in the formation of formally zwitterionic Ph(3)PO(CH(2))(4)TeBr(4) (3). This reaction involves an unprecedented THF ring opening in which the oxygen atom becomes bonded to the phosphorus atom of triphenylphosphine and the carbon atom at the other end of the five-atomic chain becomes bonded to the tellurium atom of TeBr(4). The ring opening of the solvent THF is also taking place in the reaction involving tellurium tetraiodide, as indicated by the formation of C(4)H(8)TeI(2) (5). The reaction may initially lead to Ph(3)PI(2) that reacts with THF yielding Ph(3)PO and ICH(2)(CH(2))(2)CH(2)I. The latter species reacts with elemental tellurium producing 5. Depending on the conditions upon crystallization, two polymorphs of C(4)H(8)TeI(2) (5a and 5b) are observed. While the molecular structures of the two forms are virtually identical, their packing and intermolecular contacts are different. Two further minor products (6a and 6b) were isolated in the reaction of TeI(4) and PPh(3): Both are formally 1:1 adducts of 5 and TeI(4), but they differ considerably in their structures. 6a can be formulated as [C(4)H(8)TeI(+)](2)[Te(2)I(10)(2-)] and 6b as [C(4)H(8)TeI(+)](2)(TeI(3)(+))(2)(I(-))(4). The latter compound exhibits framework similar to that of the tetramers in gamma- and delta-TeI(4).

Coordination chemistry of the main group elements with phosphine, arsine and stibine ligands

“…Selenium(IV) and tellurium(IV) halides are reduced by phosphines; the complex mixture of products formed depends upon the reaction conditions, but the primary reaction is the formation of halophosphorus(V) cations [PR 3 X] + and selenium or tellurium anions, sometimes along with elemental Se or Te [344][345][346]. In the presence of air and moisture, the major products with TeX 4 are protonated phosphine oxide salts of halotellurates(IV) [346].…”

“…In the presence of air and moisture, the major products with TeX 4 are protonated phosphine oxide salts of halotellurates(IV) [346]. Careful bromination of phosphine selenides affords [(R 3 P)SeBr 2 ] R = NMe 2 , NEt 2 , Cy, i Pr, t Bu) which have T-shaped geometries at Se (10e − systems) and are formally phosphine complexes of SeBr 2 [347,348].…”

Twinning by merohedry in bis(4-methoxyphenyl)tellurium(IV) diiodide dimethyl sulfoxide hemisolvate

“…During crystallization trials of (I), we observed the formation of crystals of various morphologies and colours, depending on the solvents and conditions used. This observation, and the well known facts that organotellurium(IV) iodides frequently display secondary bonding, which gives rise to a wide variety of supramolecular assemblies ), that they are often polymorphic [see, for example, McCullough et al (1985), Nä rhi et al (2004), Srivastava et al (2004) and Beckmann et al (2005), and references therein], and that they have colours that are related to the occurrence of noncovalent interactions (McCullough et al, 1985;Dewan & Silver, 1977), led us to a systematic study of these specimens.…”

Tellurium: Organic and Organometallic Compounds

“…It was reported already in the early 1930s that this compound crystallizes as two different polymorphs: one form is orange red and the other deep red. 81 The crystal structures of both polymorphs were established recently 79 and show that the I· · ·I contacts in the deeper red polymorphs are shorter than in the orange -red polymorph. The packing of molecules in both polymorphs is shown in Figure 9.…”

“…It has been reported that there is a qualitative correlation between the lengths of the Te-I bonds in R 2 TeI 2 and the strength of the secondary bonding interactions, 79 though the bond lengths are naturally also affected by the organic group. McCullough et al 80 have correlated the secondary bonds with the color of the crystalline material.…”