Dibromidochlorido{2-[(dimethylamino)methyl]phenyl-κ²N,C¹}tellurium(IV)

Abstract

The title compound, C9H13Br2ClNTe, was synthesized by reacting [2-(dimethyl­amino­meth­yl)phen­yl]tellurium(II) chlor­ide with Br2. As a consequence, the Cl and Br atoms are not well ordered but distributed over the three possible positions such that the overall stiochiometry is two Br atoms and one Cl atom. The scrambling of the Br and Cl atoms indicates a small energy barrier for the exchange process between the apical and equatorial positions. Overall, the Te atom geometry is slightly distorted square pyramidal (τ = 0.052 for the major component). However, there is a weak secondary inter­action between the Te atoms and the disordered Br/Cl atoms of a nearby mol­ecule. The Te—Br and Te—Cl distances in both disorder components fall into two groups; a longer distance for the Br/Cl involved in this secondary inter­action [2.6945 (17) Å for Br and 2.601 (9)Å for Cl] and shorter bond distances to the remaining halogen atoms, indicating that this inter­action has slightly weakened the Te—X bond, as is the case in the previously reported tribromido structure [Singh et al. (1990). J. Chem. Soc. Dalton Trans. pp. 907–913]. Otherwise, the metrical parameters in the two structures are not significantly different. An intermolecular C—H⋯Br interaction occurs.

Intramolecularly Coordinated 2‐Iminomethylphenyltellurium Compounds

“…The Te–N bond length of the tellurenyl(II) chloride 3a [2.203(2) Å] is slightly shorter than that of the tellurium(IV) trichloride 4a [2.286(1) Å], despite the higher oxidation state of the Te atom in 4a . In related compounds containing 2‐dimethylaminomethylphenyl groups ( I , Scheme ) and the 8‐dimethylaminonaphthyl group ( III , Scheme ), the same trend regarding the oxidation states can be observed, however, the Te–N bond lengths are generally longer, for example, 2‐Me 2 NCH 2 C 6 H 4 TeCl [2.355(3) Å] versus 2‐Me 2 NCH 2 C 6 H 4 TeCl 3 [2.406(3) Å] and 8‐Me 2 N‐Nap‐1‐TeCl [2.340(3) Å] versus 8‐Me 2 N‐Nap‐1‐TeCl 3 [2.420(3) Å] …”

“…This bond length in 3a is also slightly shorter than that in the direct analogue 2‐( p‐ TolylNCH)C 6 H 4 TeCl [2.218(6) and 2.239(6) Å for two independent molecules in the unit cell] . In turn, the Te–Cl bond length of 3a [2.612(1) Å] is longer than those of the related tellurium(II) chlorides 2‐Me 2 NCH 2 C 6 H 4 TeCl [2.566(1) Å], 8‐Me 2 N‐Nap‐1‐TeCl [2.546(2) Å], and 2‐( p‐ TolylNCH)C 6 H 4 TeCl [2.582(2) and 2.553(2) Å for two independent molecules in the unit cell] . In the tellurium(IV) trichloride 4a , the Te–Cl bond in the trans position with respect to the N atom is slightly shorter [2.467(1) Å] than those in the cis position [2.484(1) and 2.526(1) Å].…”

“…Unlike its lighter congeners, some basic compound classes, including tellurenyl cations and tellurenyl (pseudo)halides, tellurium oxides, and tellurones as well as tellurinic and telluronic acids, have been established only in the last two decades . The stabilization of these tellurium compounds often relied on the judicious choice of aryl substituents containing intramolecularly coordinating N(sp 3 )‐donor ligands, such as the “one‐arm” 2‐dialkylaminomethylphenyl group ( I ), the “two‐arm” 2,6‐bis(dialkylaminomethylphenyl) group ( II ), and the “stiff‐arm” 8‐dialkylaminonaphthyl group ( III , Scheme ) , . These ligands are complemented by aryl substituents containing intramolecularly coordinating N(sp 2 )‐donor ligands, such as the 2‐pyridylphenyl group ( IV ), the 2‐oxazolinylphenyl group ( V ),, and the 2‐iminomethylphenyl group ( VI , Scheme ) , .…”