Bismuth(III) Iodide Complexes with 1-Ethyl-4-Dimethylaminopyridinium: Structure, Thermal Stability, and Optical Properties

Abstract

Polynuclear bismuth(III) iodide complexes with 1-ethyl-4-dimethylaminopyridinium (1-EtDMAP)4[Bi8I28] (1) and (1-EtDMAP)BiI4 (2) have been obtained by the reactions of bismuth(III) iodide with an organic iodide salt cations in organic solvents and characterized by X-ray diffraction. The optical properties and thermal stability of the obtained compounds have been studied.

Unexpected Polymorphism in Bromoantimonate(III) Complexes and Its Effect on Optical Properties

Reactions of [SbBr₆]^3- containing HBr solutions with bromide salts of 1,1'-(1,2-ethanediyl)bis(pyridine) (PyC₂²⁺) or 1,1'-(1,2-ethanediyl)bis(3,5-dimethylpyridine) (3,5-MePyC₂²⁺) initially result in the formation of the deep orange complexes Cat[SbBr₅] (1 and 2), featuring unusual Sb···Br interactions in the solid state. In the mother liquor, 1 transforms into discrete binuclear (C₂Py)₂[Sb₂Br₁₀], which demonstrates polymorphism (triclinic 3 and monoclinic 4), while 2 transforms into polymeric (3,5-MePy){[SbBr₄]} (5). DFT calculations reveal that the system of noncovalent Sb···Br contacts may be responsible for the appearance of the observed optical properties (unusual deep orange coloring).

Thermochromism of bromotellurates(iv): experimental insights

Thermally induced changes in optical properties (thermochromism) in an extended series of 16 bromotellurate(iv) complexes were investigated; regularities valid for this class of compounds were established.

Highly Emissive Self-Trapped Excitons in Fully Inorganic Zero-Dimensional Tin Halides

The spatial localization of charge carriers to promote the formation of bound excitons and concomitantly enhance radiative recombination has long been a goal for luminescent semiconductors. Zero-dimensional materials structurally impose carrier localization and result in the formation of localized Frenkel excitons. Now the fully inorganic, perovskite-derived zero-dimensional SnII material Cs4 SnBr6 is presented that exhibits room-temperature broad-band photoluminescence centered at 540 nm with a quantum yield (QY) of 15±5 %. A series of analogous compositions following the general formula Cs4-x Ax Sn(Br1-y Iy )6 (A=Rb, K; x≤1, y≤1) can be prepared. The emission of these materials ranges from 500 nm to 620 nm with the possibility to compositionally tune the Stokes shift and the self-trapped exciton emission bands.

One-dimensional polymeric polybromotellurates(iv): structural and theoretical insights into halogen⋯halogen contacts

Reactions of TeO₂and Br₂in concentrated HBr in the presence of various organic cations resulted in the formation of one-dimensional supramolecular polymers with the structure cation₂{[TeBr₆](Br₂)}.