Phase transitions and properties of 0D hybrid iodoantimonate(III) and iodobismuthate(III) semiconducting ferroics: [C(NH2)3]3Bi2I9 and [C(NH2)3]3Sb2I9

Ternary Complexes of BiI3/CuI and SbI3/CuI with Tetrahydrothiophene

Reactions of BiI3/CuI mixtures with tetrahydrothiophene (THT) in toluene produce 2-D sheet networks BiCu3I6(THT)n (n = 2, 3, or 4), depending on reaction conditions. All three structures are based on BiI6 octahedra, which share pairs of (μ2-I)2 with Cu3(THT)n units. BiCu3I6(THT)2 features Cu2(μ2-I)2 rhombs with close Cu···Cu interactions and is accompanied by formation of the very complex HBi3Cu12I22(THT)8. Reactions of SbI3/CuI with THT in toluene produced a SbCu3I6(THT)2 network shows Cu3(μ2-THT)2 units, like its Bi congener, but Cu6(μ2-I)6 barrels rather than rhombs. Isolated SbI3 units are stacked above the Cu6I6 barrels. A molecular compound, Sb3Cu3I12(THT)6 consists of a face-sharing Sb3I12 stack, in which the Cu-THT units are bonded in asymmetric fashion about the central SbI6. Metal-halide bonds were investigated via QTAIM and NLMO analyses, demonstrating that these bonds are largely ionic and occur between the Bi/Sb and I p orbitals. Hirshfeld analysis shows significant H···H and H···I interactions. Diffuse reflectance spectroscopy (DRS) reveals band edges for the Bi species of 1.71-1.82 eV, while those for the neutral Sb complexes are in the range of 1.94-2.06 eV. Mapping of the electronic structure via density of state calculations indicates population of antibonding Bi/Sb-I orbitals in the excited state.

Temperature symmetry breaking and properties of lead-free organic-inorganic hybrids: bismuth(III) iodide and antimony(III) iodide: (S(CH3)3)3[Bi2I9] and (S(CH3)3)3[Sb2I9]

We have synthesized and characterized two novel lead-free organic-inorganic hybrid crystals: (S(CH3)3)3[Bi2I9] (TBI) and (S(CH3)3)3[Sb2I9] (TSI). Thermal DSC, TG, and DTA analyses indicate structural phase transitions (PTs) in both compounds; TBI undergoes two structural phase transitions at 314.2/314.8 K (cooling/heating) and at 181.5 K of first (I ↔ II) and second order (II ↔ III), respectively. The crystal structures of TBI are refined for phases I (325 K), II (200 K) and III (100 K). TBI exhibits ferroelastic properties since both PTs are accompanied by a change in the symmetry of crystals: P63/mmc → C2/c (I → II) and C2/c → P1̄ (II → III). The presence of a ferroelastic domain structure has been confirmed by optical observations. In turn, TSI also reveals two PTs: I ↔ II (at 303.9/304.1 K) and II ↔ III (212.9/221.4 K). To compare and obtain insight into the mechanism of the PTs of TBI, we have carried out temperature dependent single crystal X-ray diffraction studies. Additionally, to confirm the change in the dynamical states of molecules in PTs, dielectric measurements have been carried out between 100 K and 400 K in the frequency range of 200 Hz to 2 MHz. Moreover, the measurements of the 1H NMR spin-lattice relaxation time, T1, and a second moment, M2, of the 1H NMR line have been undertaken in the temperature range between 100 and 300 K.

Trimethylammonium Sn(IV) and Pb(IV) Chlorometalate Complexes with Incorporated Dichlorine

Supramolecular dichloro-chlorostannate(IV) and -plumbate(IV) complexes (Me3NH)2{[MCl6]Cl2} (M = Sn (1), Pb (2)) feature dichlorine units incorporated into a halometalate framework. Both compounds were characterized by X-ray diffractometry and Raman spectroscopy.

Recent advances on structural, thermal, vibrational, optical, phase transitions, and catalysis properties of alkylenediammonium halogenometallate materials (Metal: Bi, Sb, Halogen: Cl, Br, I)

This paper aims to review recent advances on synthesis, crystal structures, thermal, spectroscopic, phase transitions, optical, dielectric, and catalysis properties of hydrate and anhydrous alkylenediammonium halogenometallates materials (Metal: Bi, Sb, Halogen: Cl, Br, I). These hybrid materials present rich structural diversities based on octahedra forming infinite zero dimensional, 1-dimensional chains, 2-dimensional layers, discrete bioctahedra, and discrete tetramer units. The effect, contribution and importance of hydrogen bonding N–H … X (X: Cl, Br, I) are reviewed in terms of solid state relationship. Particularly, a comparative study is made on hydrate and anyhdrous aliphatic chlorobismuthates with alkylenediammonium +NH3(CH2) n NH3 + based on structural data and V/Z variation with (CH2) n chains (n = 2–8, 12), and variation of BiCl6 3− Raman frequencies modes versus (CH2) n chains (n = 3–8). Hydrate salts with (n = 3, 12) consist of isolated BiCl6 3− anions and two water molecules, against others ones with isolated anionic chains [BiCl5 2−] n or Bi2Cl10 4− dimers, formed by distorted octahedra BiCl6 3− sharing corners, vices or edges. The reviewed optical and electronic band gaps suggested interesting compounds with band gaps (1.85–2.4 eV), as suitable materials in optoelectronic properties, photoactive layer in solution-processed photovoltaics, and bio-imaging or photovoltaic applications. It was concluded that iodobismuthate salts have generally the lowest bands gap, compared to that of bromo and chlorobismuthate slats. Catalysis proprieties are reviewed n fast (RhB) degradation under dark conditions for (C4N2H7)4Bi2Cl10, (C5H9N2)BiI4, and {(H-BPA)4·[(BiI6)I13]·2I3} n , and in organic salts synthesis under solvent-free conditions. Herein NH3(CH2) n NH3BiCl5 (n = 5–7) salts were used as highly efficient catalysts, which is a novel tendency in chlorobismuthate researchs in the green chemistry field.

(C3N2H5)3Sb2I9 and (C3N2H5)3Bi2I9: ferroelastic lead-free hybrid perovskite-like materials as potential semiconducting absorbers

We have synthesised and characterised novel organic-inorganic hybrid crystals: (C₃N₂H₅)₃Sb₂I₉ and (C₃N₂H₅)₃Bi₂I₉ (PSI and PBI). The thermal DSC and TG analyses indicate four structural phase transitions (PTs) at 366.2/366.8, 274.6/275.4, 233.3/233.3 and 142.8/143.1 K (on cooling/heating) for PSI and two reversible PTs at 365.2/370.8 and 252.6/257.9 K for PBI. Both analogues crystallize at room temperature in the orthorhombic Cmcm structure, which transforms, in the case of PBI, to monoclinic P2₁/n at low temperature. According to the X-ray diffraction results, the anionic component is discrete and built of face-sharing bioctahedra, [M₂I₉]^3-, in both compounds, whereas cations exhibit distinct dynamical disorder over high temperature phases. Dielectric spectroscopy and ¹H NMR spectroscopy have been used to characterise the dynamical state of the C₃N₂H₅⁺ cations. The ferroelastic domain structure has been characterised by observations under a polarized optical microscope. Both compounds are semiconductors with narrow bandgaps of 1.97 eV (PBI) and 2.10 eV (PSI).