Phosphine Selenide Arenetellenyliodide Complexes and Telluroselenophosphonium Salts

Abstract

Trialkylphosphine selenides tBu _n iPr_{3− n} PSe (n = 3, 2, 1, 0) and bidentate phosphine selenides (dppmSe₂, dppeSe₂) react with arenetellurenyl iodides (RTeI) furnishing complexes tBu _n iPr_{3− n} PSeTe(R)I (R = p-tolyl, p-anisyl, mesityl [Mes]), dppm[SeTe(Mes)I]₂ and dppe[SeTe(Mes)I]₂ that contain Se-Te(R)-I moieties (10-Te-3). Dppe[SeTe(Mes)I]₂ exhibits supramolecular soft-soft interactions by “T-stacking” of the Se-Te(R)-I functions in the solid. When trialkylphosphine selenides tBu _n iPr_{3− n} PSe react with two equivalents of RTeI, novel trialkyl(aryltelluroseleno)phosphonium diiodotellurate(II) salts are formed. In solid [(tBu₂iPrPSeTe-p-Tol)⁺(p-TolTeI₂)⁻] the Te atom from the (p-TolTeI₂)⁻anion behaves as soft donor towards the formally uncharged Te atom in the cation (tBu₂iPrPSeTe-p-Tol)⁺exhibiting a novel type of Te…Te anion → cation donor-acceptor interaction (Te…Te 318 pm). Loss of mesityl groups in course of reactions with MesTeI led to a unique iodotelluroselenophosphonium salt {[(iPr₃PSeTeI)⁺]₂(TeI₆)²⁻} with chelating cation-anion Te ^II …I-Te ^IV contacts, to the six-membered chelate complex dppmSe₂TeI₂ with a square planar cis-Se₂TeI₂ group, and to dppeSe₂TeI₂ with trans-Se₂TeI₂ groups in a helical chain structure.

Keywords:

• Cation-anion interactions
• donor-acceptor complexes
• phosphonium salts
• soft-soft interactions
• supramolecular structures
• tellurium iodides

Acknowledgments

We thank Prof. Dr. P. G. Jones and Prof. Dr. L. Ernst (Braunschweig, Germany) for support with X-ray crystallography and NMR spectroscopy.