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Zero-dimensional (0D) organic–inorganic metal halides (OIMHs) hold promise in photoluminescence properties and related applications. Thus far, the photoluminescence quantum yields (PLQYs) of the reported 0D hybrid antimony(III) bromides (HABs) are not as high as those of the chloride analogs; therefore, the improvement of PLQY is an important issue for luminescent HABs. Herein, a supramolecular interaction adjustment strategy to improve the PLQYs of HABs is proposed. Two isostructural 0D HABs that crystallize with different lattice solvent molecules, namely [EtPPh3]2[SbBr5]·EtOH (1·EtOH-Br; EtPPh3 = ethyltriphenylphosphonium; EtOH = ethanol) and [EtPPh3]2[SbBr5]·MeCN (1·MeCN-Br; MeCN = acetonitrile), have been synthesized. Both of them exhibit typical self-trapped exciton (STE) photoluminescence (PL) with broad emission, a large Stokes shift and a long lifetime. They show deviation in deep-red emission peaks (655 nm vs. 661 nm) owing to the difference in the distortion level of [SbBr5]2− anions. Most importantly, 1·EtOH-Br exhibits a nearly one-fold enhancement in PLQY compared to 1·MeCN-Br (18.26% vs. 9.29%). Density functional theory (DFT) calculations, hydrogen bonding analysis and Hirshfeld surface analysis suggest that the PLQY enhancement is due to the structural rigidity improvement brought by hydrogen bonding adjustments between the inorganic [SbBr5]2− anions and solvent molecules. This work provides a new insight into the structure–property relationship study and PLQY improvement for 0D OIMHs. [ABSTRACT FROM AUTHOR]

Although luminescent indium(III) based halide perovskites have been widely investigated, the study of emissive indium(III) halide hybrids is limited. Three indium(III) chloride hybrids based on a bpym ligand were synthesized, namely [EPy]2[InCl4(bpym)InCl4]·DMF (1), [EPy]2[InCl4(bpym)InCl4] (2), and [BPy]2[InCl4(bpym)InCl4] (3) (EPy = N-ethylpyridinium; BPy = N-butylpyridinium; bpym = 2,2′-bipyrimidine). They all exhibit a zero-dimensional structure, in which the ligand bpym interconnects two [InCl4]− to form a [InCl4(bpym)InCl4]2− anion that is further charge-compensated by the corresponding pyridinium cations. This is the first time using bpym to coordinate with an In atom. At 298 K, 1 exhibits a weak emission at 600 nm while 2 and 3 exhibit emissions peaking at 500 nm and 540 nm, respectively. Interestingly, the DMF solvent molecule in 1 can be removed by heating, thus resulting in the structural transformation of 1 into 2 together with a photoluminescence (PL) change. Density functional theory (DFT) calculations confirm that halogen-to-ligand charge-transfer (HLCT) occurs in the emission process. To the best of our knowledge, this is the first report on PL of ionic indium(III) halide hybrids incorporating organic ligands. [ABSTRACT FROM AUTHOR]

Zero-dimensional (0D) organic–inorganic hybrid metal halides (OIMHs) containing multiple halometallate species (HMSs) have received extensive attention due to their capability to achieve multifunctional photophysical characteristics. Herein we report a lead-free 0D-OIMH compound, namely [Emim]8[SbCl6]2[SbCl5] (1, Emim = 1-ethyl-3-methylimidazolium), which is the first crystal containing two distinct mononuclear [SbXn]3−n units in one single structure. The optical absorption, temperature/excitation-variable photoluminescence (PL) and PL decay were studied. 1 exhibits a broad emission centered at 577 nm, which is analyzed to be a combination of the emissions from [SbCl6]3− and [SbCl5]2−. The structural effects including Sb⋯Sb distances and polyhedral distortion of [SbXn]3−n on the PL of antimony-based 0D-OIMHs are discussed in detail. This work would provide guidance for constructing Sb-based 0D OIMHs composed of multiple halometallate species. [ABSTRACT FROM AUTHOR]

The different hydrogen bond interactions in two organic–inorganic hybrid manganese halide compounds, namely [A]2[MnBr4] (A = N-butyl-N-methylpyrrolidinium ([P14]+) for (1) and N-butyl-N-methylpiperidinium ([PP14]+) for (2)), lead to distinct photoluminescence quantum yields (81% for 1; 55% for 2). Further applications of luminescent 1 are also developed. [ABSTRACT FROM AUTHOR]

Differences in the electronegativity and hydrophilicity of halogens lead to differences in proton-conducting and photoluminescence properties in hybrid organic–inorganic lead halide compounds of [PbX2(OOCMMIm)]n (X = Cl (1), Br (2), HOOCMMIm = 1-carboxymethyl-3-methylimidazolium). [ABSTRACT FROM AUTHOR]

Here reports the first example of single-crystal-to-single-crystal transformation between two zero-dimensional metal halide isomers containing lattice solvent molecules, which leads to the regulation of the photoluminescence performance and optimization of white LED device. [Display omitted] • The first example of single-crystal-to-single-crystal (SCSC) transformation between two isomers containing lattice solvent molecules in zero-dimensional metal halides. • Regulating photoluminescence (PL) properties has been realized by SCSC transformation. • The mechanisms of title compounds' PL emission and the PL regulation brought by SCSC transformation have been clarified. • Benefitting from the PL regulation brought by SCSC transformation, the white LED device has been optimized and its CRI has reached as high as 95.3. Regulating photoluminescence (PL) properties induced by single-crystal-to-single-crystal (SCSC) transformation has sparked significant interest in the research of zero-dimensional organic–inorganic metal halides (0-D OIMHs). To best of our knowledge, the SCSC transformation of solvent-containing 0-D OIMH isomers hasn't been reported yet. In this work, we report the first example of SCSC transformation between two isomers containing lattice solvent molecules, namely α - and β -[EtPPh 3 ] 2 [SbCl 5 ]·MeCN ( α - and β - 1·MeCN ; EtPPh 3 = ethyltriphenylphosphonium; MeCN = acetonitrile). Differential scanning calorimetry (DSC) results show that the SCSC transformation from α - to β - 1·MeCN is an exothermic process, implying that β - 1·MeCN is a more stable phase than α - 1·MeCN. Moreover, α - and β - 1·MeCN exhibit bright orange (emission peak: 610 nm) and red (emission peak: 635 nm) emission under 360/365 nm excitation, respectively. DFT calculations suggest that the negligible self-absorption and a strong exciton confinement contribute to their effective PL emission. By analyzing temperature-dependent PL spectra, β - 1·MeCN has been found to exhibit stronger electron-phonon coupling under excitation than α - 1·MeCN. Thus, the broader emission with full width at half maximum (FWHM: 134 vs. 147 nm) and the higher photoluminescence quantum yield (PLQY: 40.37% vs. 70.50%) have been realized by SCSC transformation from α - to β - 1·MeCN by heating at 92 °C. Benefitting from the regulation of PL performances brought by SCSC transformation, the white light-emitting-diode (LED) devices assembled by using β - 1·MeCN as red phosphor could be optimized, and the CRI reaches as high as 95.3. [ABSTRACT FROM AUTHOR]

Abstract: We report on the ionothermal synthesis of a novel two-dimensional (2D) cadmium metal organic framework, namely, [Emim][CdBr(1,4-NDC)] (1) (Emim=1-ethyl-3-methylimidazolium, 1,4-NDCH2 =1,4-naphthalenedicarboxylic acid) using an ionic liquid (IL) [Emim]BF4 or mixed ILs of [Emim]BF4 and [Emim]Br both as solvent and template. Single-crystal X-ray diffraction reveals that the structure features an anionic two-dimensional network based on the paddle wheel-like cluster. The imidazolium cations acting as charge compensating agent intercalate into the interlayer spaces. The current result is the first example of ionothermal synthesis of 1,4-NDC based metal organic framework. The thermal and photoluminescent properties have also been investigated. [Copyright &y& Elsevier]

Abstract: Three coordination polymers containing 2-(2-pyridyl)benzimidazole (PyHBIm) ligand, namely {[Zn3(PyBIm)3(PyHBIm)2(tma)(H2O)]•H2O}n (1), [Zn(PyHBIm)(oba)]n (2), [Cd(PyHBIm)(oba)]n (3), (tma=trimesate, oba=4,4′-oxybis-(benzoate)), have been prepared through hydrothermal reaction. Compound 1 exhibits one-dimensional (1D) helical structure. However, compounds 2 and 3 display 1D meso -helical structure. These 1D structures are further assembled into three-dimensional (3D) networks through aromatic π–π stacking interactions and hydrogen bonding interactions. Moreover they all exhibit strong photoluminescence at room temperature and may be good candidates for potential luminescence materials. [ABSTRACT FROM AUTHOR]

In this review, the structures of halometallate anions based on s2 typed metal ions (Ge2+, Sn2+, Pb2+, Sb3+, Bi3+, Te4+) that are induced by organic cations are summarized. The syntheses, structures, and photoluminescence properties for s2 typed halometallates based on aprotic ionic liquids are presented. In addition, the future challenges and prospects are discussed. [Display omitted] • Organic cation induced s2 typed (e.g., Sb3+,Bi3+) halometallate anions are described. • Luminescent s2 typed halometallates based on aprotic ionic liquids are summarized. • The prospects and the current challenges for s2 typed halometallates are discussed. Photoluminescence (PL) plays an important role in our daily life as it could be applied to bioimaging, sensing, illumination, display, etc. Inorganic-organic hybrid materials that contain both organic and inorganic parts have widely emerged owing to the achievable dual functions from both organic and inorganic parts. Ionic liquids (ILs) have been widely used as a "green" solvent in the synthesis of functional materials. Especially, relatively chemically stable aprotic ILs have been widely emphasized owing to no proton-transfer and no (or low) volatility. s2 typed metal ions (e.g. , Ge2+, Pb2+, Sn2+, Sb3+, Bi3+, Te4+) are potential emissive ions. They are easily coordinated with halogen ions to form s2 typed halometallates. Diverse assemblies of the aprotic ionic liquid cations (AILCs) with the s2 typed halometallate anions could result in a new class of inorganic–organic hybrid ionic metal halides (IOMHs) with excellent and tunable PL properties. This review summarizes the recent progress on the syntheses, structures, and PL properties of IOMHs with the formulas of [AILC] a [ M b X c L d ] (M = s2 typed metal ion, X = halogen, L = N or O-donor organic ligand). Firstly, two types of halometallate anions based on s2 typed metal ions are structurally classified, namely the pure inorganic halometallate anions and the one with coordinating N or O-donor organic ligands; the latter mainly are haloantimonates and halobismuthates. Furthermore, the structural characteristics of IOMHs consisting of s2 typed halometallates and AILCs are provided, followed by the detailed interpretations of their syntheses, structures and PL properties, the PL-structure relationships and luminescent mechanisms. Finally, an outlook about the main challenges and opportunities in this topic are proposed. [ABSTRACT FROM AUTHOR]