Crystal structure, spectroscopic measurement, optical properties, thermal studies and biological activities of a new hybrid material containing iodide anions of bismuth(iii)

As part of our interest in halogenobismuthate(iii) organic-inorganic hybrid materials, a novel compound named bis(4,4'-diammoniumdiphenylsulfone) hexadecaiodotetrabismuthate(III) tetrahydrate with the chemical formula (C12H14N2O2S)2[Bi4I16]·4H2O, abbreviated as (H2DDS)[Bi4I16], has been prepared by a slow evaporation method at room temperature. This compound was characterized by single crystal X-ray diffraction (SCXRD), spectroscopic measurements, thermal study and antimicrobial activity. The examination of the molecular arrangement shows that the crystal packing can be described as made of layers of organic [C12H14N2O2S]2+ entities and H2O molecules, between which tetranuclear [Bi4I16]4- units, isolated from each other, are inserted. The cohesion among the different molecules is assured by N-H⋯I, N-H⋯O and O-H⋯I hydrogen bonding interactions, forming a three-dimensional network. Room temperature IR, Raman spectroscopy of the title compound were recorded and analyzed. The optical properties were also investigated by both UV-vis and photoluminescence spectroscopy. Moreover, the synthesized compound was also screened for in vitro antimicrobial (Gram-positive and Gram-negative) and antioxidant activities (scavenging effect on DPPH free radicals, reducing power and total antioxidant capacity).

Halobismuth(III) salts with substituted aminopyridinium cations

The crystal structures of six halobismuth(III) salts of variously substituted aminopyridinium cations display discrete mononuclear [BiCl₆]^3- and dinuclear [Bi₂X₁₀]^4- anions (X = Cl or Br), and polymeric cis-double-halo-bridged [Bi_nX_4n]^n- anionic chains (X = Br or I). Bis(2-amino-3-ammoniopyridinium) hexachloridobismuth(III) chloride monohydrate, (C₅H₉N₃)₂[BiCl₆]Cl·H₂O, (1), contains discrete mononuclear [BiCl₆]^3- and chloride anions. Tetrakis(2-amino-3-methylpyridinium) di-μ-chlorido-bis[tetrachloridobismuth(III)], (C₆H₉N₂)₄[Bi₂Cl₁₀], (2), tetrakis(2-amino-3-methylpyridinium) di-μ-bromido-bis[tetrabromidobismuth(III)], (C₆H₉N₂)₄[Bi₂Br₁₀], (3), and bis(4-amino-3-ammoniopyridinium) di-μ-chlorido-bis[tetrachloridobismuth(III)] dihydrate, (C₅H₉N₃)₂[Bi₂Cl₁₀]·2H₂O, (4), incorporate discrete [Bi₂X₁₀]^4- anions (X = Cl or Br), while catena-poly[2,6-diaminopyridinium [[cis-diiodidobismuth(III)]-di-μ-iodido]], {(C₅H₈N₃)[BiI₄]}_n, (5), and catena-poly[2,6-diaminopyridinium [[cis-dibromidobismuth(III)]-di-μ-bromido]], {(C₅H₇N₂)[BiBr₄]}_n, (6), include [Bi_nX_4n]^n- anionic chains (X = Br or I). Structures (2) and (3) are isostructural, while that of (5) is a pseudomerohedral twin. There is no discernible correlation between the type of anionic species obtained and the cation or halide ligand used. The Bi^III centres always have a slightly distorted octahedral geometry and there is a correlation between the Bi-X bond lengths and the number of classic N-H...X hydrogen bonds that the X ligand accepts, with a greater number of interactions corresponding with slightly longer Bi-X distances. The supramolecular networks formed by classic N-H...X hydrogen bonds include ladders, bilayers and three-dimensional frameworks.

Ferroelectricity in Ethylammonium Bismuth-Based Organic-Inorganic Hybrid: (C2H5NH3)2[BiBr5]

The (C₂H₅NH₃)₂[BiBr₅] (EBB) crystals adopt the one-dimensional (1D) polymeric anionic form [BiBr₅]_∞^2-, which is preferred by halobismuthates(III) exhibiting polar properties and realized in R₂MX₅ stoichiometry. Differential scanning calorimetry and dilatometric measurements reveal reversible structural phase transitions: at 160 K (phase I → phase II) and 120 K (phase II → phase III). The resolved crystal structures of EBB show the centrosymmetric space group in phase I (Aeam), polar (Pca2₁) in phase II, and polar (Aea2) in phase III. The presence of dielectric hysteresis loops in phases II and III evidence ferroelectric properties. The dielectric response [ε*(ω,T)] of EBB close to 160 K is characteristic of ferroelectrics with a critical slowing down process. The molecular mechanism of a paraelectric-ferroelectric phase transition at 160 K is explained as "order-disorder" (assigned to the dynamics of the ethylammonium cations) and dominating "displacive" (related to strong distortion of the 1D anionic network). The optical band gap obtained from UV-vis measurements is about 2.6 eV. The conduction band minimum is formed by the hybridized Bi 6p and Br 4p states. An analysis of the CSD results for haloantimonates(III) and halobismuthates(III) ferroelectrics characterized by [MX₄]^-, [M₂X₉]^3-, [MX₅]^2-, and [M₂X₁₁]^5- anions is given.

Semiconducting crystalline inorganic-organic hybrid metal halide nanochains

One-dimensional (1D) inorganic-organic metal halide hybrids at the molecular level, which can be considered as arrays of nanochains isolated by organic components, have shown remarkable optical and electric properties. This review summarizes their reported structural types and shows how to modify their band gaps and optical and electric properties.

Chlorotellurate(iv) supramolecular associates with “trapped” Br2: features of non-covalent halogen⋯halogen interactions in crystalline phases

Reactions of chlorotellurates(iv) and Br₂ afford formation of supramolecular complexes Cat₂{[TeCl₆](Br₂)} (Cat = Me₃N⁺ (1), PyH⁺ (2), 4-MePyH⁺ (3) and 1-MePy⁺ (4)) where dibromine fragments are “trapped” by [TeCl₆]³⁻via Br⋯Cl halogen bonding.

11/15/17 Complexes as Molecular Models for Metal Halide Double Perovskite Materials

Thirteen neutral complexes [E _xM _yX _z(PPh₃) _n(L) _m] (E = Bi, Sb; M = Cu, Ag; X = Cl, Br, I; L = solvent) featuring three different motifs were prepared and characterized regarding their structure, stability, and absorption spectra. While not identical in structural motif, the compounds can serve as models for the influence of the composition E/M/X on the optical properties of double perovskites A₂EMX₆ (A = Cs, CH₃NH₃).

Investigations of organic–inorganic hybrids based on homopiperidinium cation with haloantimonates(iii) and halobismuthates(iii). Crystal structures, reversible phase transitions, semiconducting and molecular dynamic properties

A description of the thermal, structural, ¹H NMR, electric and optical properties of novel organic–inorganic hybrids.