A Phosphorylated Dendrimer-Supported Biomass-Derived Magnetic Nanoparticle Adsorbent for Efficient Uranium Removal

A novel biomass-based magnetic nanoparticle (Fe3O4-P-CMC/PAMAM) was synthesized by crosslinking carboxymethyl chitosan (CMC) and poly(amidoamine) (PAMAM), followed by phosphorylation with the incorporation of magnetic ferric oxide nanoparticles. The characterization results verified the successful functionalization and structural integrity of the adsorbents with a surface area of ca. 43 m2/g. Batch adsorption experiments revealed that the adsorbent exhibited a maximum adsorption capacity of 1513.47 mg·g-1 for U(VI) at pH 5.5 and 298.15 K, with Fe3O4-P-CMC/G1.5-2 showing the highest affinity among the series. The adsorption kinetics adhered to a pseudo-second-order model (R2 = 0.99, qe,exp = 463.81 mg·g-1, k2 = 2.15×10-2 g·mg-1·min-1), indicating a chemically driven process. Thermodynamic analysis suggested that the adsorption was endothermic and spontaneous (ΔH° = 14.71 kJ·mol-1, ΔG° = -50.63 kJ·mol-1, 298. 15 K), with increasing adsorption capacity at higher temperatures. The adsorbent demonstrated significant selectivity for U(VI) in the presence of competing cations, with Fe3O4-P-CMC/G1.5-2 showing a high selectivity coefficient. The performed desorption and reusability tests indicated that the adsorbent could be effectively regenerated using 1M HCl, maintaining its adsorption capacity after five cycles. XPS analysis highlighted the role of phosphonate and amino groups in the complexation with uranyl ions, and validated the existence of bimodal U4f peaks at 380.1 eV and 390.1 eV belonging to U 4f7/2 and U 4f5/2. The results of this study underscore the promise of the developed adsorbent as an effective and selective material for the treatment of uranium-contaminated wastewater.

Halogen Substitution Regulates High Temperature Dielectric Switch in Lead-Free Chiral Hybrid Perovskites

Hybrid metal halides (HMHs) based phase transition materials have received widespread attention due to their excellent performance and potential applications in energy harvesting, optoelectronics, ferroics, and actuators. Nevertheless, effectively regulating the properties of phase transitions is still a thorny problem. In this work, two chiral lead-free HMHs (R-3FP)2 SbCl5 (1; 3FP=3-fluoropyrrolidinium) and (R-3FP)2 SbBr5 (2) were synthesized. By replacing the halide ions in the inorganic skeleton, the phase transition temperature of 2 changes with an increase of about 20 K, compared with 1. Meanwhile, both compounds display reversible dielectric switching properties. Through crystal structure analysis and Hirshfeld surface analysis, their phase transitions are ascribed to the disorder of the cations and deformation of the inorganic chains.

A room temperature ferroelectric material with photoluminescence: (1,3-dicyclohexylimidazole)2MnCl4

Molecular ferroelectric materials have been widely used in capacitors and sensors due to their low cost, light weight, flexibility and good biocompatibility. Organic-inorganic hybrid complexes, on the other hand, have received a great deal of attention in the luminescence field due to their low cost and simple preparation. The combination of ferroelectricity and photoluminescence in organic-inorganic hybrid materials not only leads to tunable optical properties, but also enriches potential applications of multifunctional ferroelectrics in optoelectronic devices. Here, we report a new luminescent ferroelectric material (1,3-dicyclohexylimidazole)₂MnCl₄ (DHIMC). Thermogravimetric analysis (TGA) was used to measure the mass change of the material at a measurement rate of 20 K min^-1 from room temperature to 900 K, and we found that this material has good thermostability, which is up to 383 K. Meanwhile, UV-vis measurements showed that it is also a fluorescent material emitting a strong green fluorescence at the wavelength of 525 nm. The ferroelectricity of the crystal was determined by two different methods: the Sawyer-Tower method and the double-wave method (DWM). Particularly, the single crystal experiences a phase transition from the ferroelectric phase to the paraelectric phase during the heating/cooling process at 318 K/313 K and the space group changes from P1̄ (centrosymmetric) to P1 (non-centrosymmetric). This work will enrich multifunctional luminescent ferroelectric materials and their application in display and sensing.

Blue-Emitting Zero-Dimensional Inorganic-Organic Hybrids Constructed from Beta-Diketonate Ligands and Bulky Organic Cations

Two zero-dimensional inorganic-organic hybrids, namely, [C₄mim][Cd(TCDPPA)₃] (1) and [C₄mpy][Cd(TCDPPA)₃] (2), where (TCDPPA)^- = 2,2,2-trichloro-N-(di(pyrrolidin-1-yl)phosphoryl)acetamide, (C₄mim)⁺ = 1-butyl-3-methylimidazolium, and (C₄mpy)⁺ = 1-butyl-4-methylpyridinium, have been synthesized via metathesis reactions and characterized systematically. These ionic cadmium-containing inorganic-organic hybrid compounds are assembled from a bulky organic cation and a complex anion constructed from the chelation of three TCDPPA ligands to one cadmium ion. These compounds possess wide band gaps and emit in the deep-blue region intensely with a quantum yield as high as 34.04%. The success of this work provides a new method for the design and fabrication of high-efficiency blue-emitting materials.

Investigation of the Solution Chemistry of Hybrid Organic-Inorganic Indium Halides for New Material Discovery

Recently, metal halide perovskites (MHPs) have emerged as a new class of materials for optical and electronic applications such as solar cells and ionizing radiation detectors. Although the solution-processability of MHPs is among their greatest advantages, the solution chemistries of most metal halide systems and their relationship with the observed structural and chemical diversity are poorly understood. In this work, we study the solution chemistry of a model indium halide system, methylammonium (MA)-In-Br, using a combination of the UV-vis spectroscopy, electrospray ionization mass spectrometry (ESI-MS) measurements, small-angle X-ray scattering (SAXS), and density functional theory (DFT) calculations. Our results show that indium could form either octahedral [InBr₆^3-] or tetrahedral [InBr₄^-] anions in solution or a combination of both, depending on the loading ratios of MABr and InBr₃ reactants. Understanding the solution chemistry of this system and recognizing the optical fingerprints of these polyanions allow for targeted crystallization of two novel compounds: MAInBr₄ featuring tetrahedral [InBr₄^-] anions and MA₂InBr₅ containing both octahedral [InBr₆^3-] and tetrahedral [InBr₄^-] anions. Further increase of the MABr content leads to the formation of previously reported MA₄InBr₇, containing only octahedral [InBr₆^3-] anions separated by Br^- anions. Our results suggest that understanding the solution chemistry of multinary metal halide systems could be a valuable tool for discovering functional materials for practical applications.

Synthesis and Characterization of a Displacement-Type Ferroelectric-Ferroelectric Phase Transition Compound [(NH3)(CH2)3(NH3)]2[InBr6]Br·H2O

Ferroelectric materials have aroused the researchers' great interest due to their wide applications. Here, a displacement-type ferroelectric-ferroelectric phase transition material [(NH₃)(CH₂)₃(NH₃)]₂[InBr₆]Br·H₂O (1) with T_c = 143 K was successfully prepared. The ferroelectric phase transition is verified by the characterization techniques such as differential scanning calorimetry, single-crystal structure elucidation, dielectric and ferroelectric measurements. The single-crystal structure elucidation reveals that the displacement and distortion of [(NH₃)(CH₂)₃(NH₃)]²⁺ cations lead to the phase transition from Cmc2₁ to Pca2₁. The spontaneous polarizations at 293 and 133 K are 0.15 and 0.12 μC·cm^-2, respectively. We expect that this work will help in further exploration of some new ferroelectric materials.

Accessing One-Dimensional Chains of Halogenoindates(III) in Organic-Inorganic Hybrids

Organic-inorganic hybrids of halogenoindates(III) are typically represented by one of the zero-dimensional units: InX₄^-, InX₅^2-, InX₆^3-, or In₂X₁₁^5-. Higher dimensional anionic forms, although not forbidden, have remained almost elusive. Here we report for the first time In³⁺-based organic-inorganic hybrids, (C₄H₅N₂S)₂InCl₅ and (C₄H₅N₂S)₂InBr₅, with 1D anionic chains of trans-halide-bridged InX₆ octahedra whose formation is guided by 2-mercaptopyrimidinium cations (C₄H₅N₂S⁺). The chains are characterized by the significant ease of deformation, which is reflected in the elongation of the bridging bonds or the displacement of In³⁺ ions. The materials show a robust band gap predominantly governed by C₄H₅N₂S⁺ cations. Dielectric relaxation processes in (C₄H₅N₂S)₂InBr₅ arise from the cations' dynamics and suggest the ability of the brominated system to accommodate even larger cations. Our work represents a successful attempt to expand the structural diversity of halogenoindates(III) and opens a pathway to reach multifunctional 1D In³⁺-based hybrids.

Zero-Dimensional Lead-Free Halide with Indirect Optical Gap and Enhanced Photoluminescence by Sb Doping

Three new lead-free organic-inorganic metal halides (OIMHs) (C₇H₈N₃)₃InX₆·H₂O (X = Cl, Br) and (C₇H₈N₃)₂SbBr₅ were synthesized. First-principles calculations indicate that the highest occupied molecular orbitals (HOMOs) of the two In-based OIMHs are constituted of π orbitals from [C₇H₈N₃]⁺ spacers. (C₇H₈N₃)₃InX₆·H₂O (X = Cl, Br) shows an indirect optical gap, which may result from this organic-contributed band edge. Despite the indirect-gap nature with extra phonon process during absorption, the photoluminescence of (C₇H₈N₃)₃InBr₆·H₂O can still be significantly enhanced through Sb doping, with the internal photoluminescence quantum yields (PLQY) increased 10-fold from 5% to 52%. A white light-emitting diode (WLED) was fabricated based on (C₇H₈N₃)₃InBr₆·H₂O:Sb³⁺, exhibiting a high color-rendering index of 90. Our work provides new systems to deeply understand the principles for organic spacer choice to obtain the 0D metal OIMHs with specific band structure and also the significant enhancement of luminescence performance by chemical doping.

Structural Phase Transition and Switchable Dielectric Behaviour of a One-Dimensional Chains Niobium Oxyfluoride

tructural phase transition is always accompanied by measurable properties change of material, which provides us more opportunities for material modification. Herein, a new niobium oxyfluoride, [HIm][NbOF4] (HIm = imidazole cation,...

Room temperature ferroelectric copper(ii) coordination polymers based on amino acid hydrazide ligands

This work brings into focus the superior coordination properties and facile applicability of amino acid hydrazide ligands for the design of molecular magnets and molecular ferroelectrics.

A multi-responsive indium-viologen hybrid with ultrafast-response photochromism and electrochromism

A novel 0D organic-inorganic metal halide hybrid (C₁₃H₁₆N₂O₂)₂InCl₆·Cl (1) has been obtained by integrating the mono-viologen derivative with InCl₃. Compound 1 exhibits reversible and ultrafast UV/sunlight/X-ray induced photochromic properties, as well as excellent electrochromic performance, which is the first example of an indium-based organic-inorganic chromic hybrid.

Two In-based organic-inorganic hybrid compounds with reversible phase transition derived from the order-disorder changes of cations or anions

Solid-state phase transition materials have received extraordinary interest due to their rich physical properties, such as thermal, dielectric, and ferroelectric properties. Here, two In-based organic-inorganic hybrid compounds, (C₆H₅CH₂CH₂NH₃)₃[InBr₅(H₂O)] (1) and [(C₃H₇)₄N][InCl₄] (2), both display reversible phase transition and dielectric response. Differential scanning calorimetry measurements indicate that the phase transition temperatures (T_c) of 1 and 2 are 167 K and 351 K, respectively. Moreover, structural analyses disclose that the phase transition of 1 can be attributed to the order-disorder changes of phenethylammonium organic cations whereas the phase transition of 2 is caused by the order-disorder changes of [InCl₄]^- anions. The phase transitions of In-based organic-inorganic hybrid compounds can be driven by the order-disorder changes of cations or anions. Therefore, the system of In-based organic-inorganic hybrid compounds is very suitable for exploring organic-inorganic hybrid phase transition materials.

Zero-Dimensional Hybrid Organic-Inorganic Indium Bromide with Blue Emission

Low-dimensional hybrid organic-inorganic metal halides have received increased attention because of their outstanding optical and electronic properties. However, the most studied hybrid compounds contain lead and have long-term stability issues, which must be addressed for their use in practical applications. Here, we report a new zero-dimensional hybrid organic-inorganic halide, RInBr₄, featuring photoemissive trimethyl(4-stilbenyl)methylammonium (R⁺) cations and nonemissive InBr₄^- tetrahedral anions. The crystal structure of RInBr₄ is composed of alternating layers of inorganic anions and organic cations along the crystallographic a axis. The resultant hybrid demonstrates bright-blue emission with Commission Internationale de l'Eclairage color coordinates of (0.19, 0.20) and a high photoluminescence quantum yield (PLQY) of 16.36% at room temperature, a 2-fold increase compared to the PLQY of 8.15% measured for the precursor organic salt RBr. On the basis of our optical spectroscopy and computational work, the organic component is responsible for the observed blue emission of the hybrid material. In addition to the enhanced light emission efficiency, the novel hybrid indium bromide demonstrates significantly improved environmental stability. These findings may pave the way for the consideration of hybrid organic In(III) halides for light emission applications.

(C2H5NH3)3[InBr6]: an indium(iii) organic–inorganic hybrid phase transition compound exhibiting a switchable dielectric response

The organic–inorganic hybrid compound (C2H5NH3)3[InBr6] undergoes a phase transition at 248/253 K, and exhibits a switchable dielectric response. The phase transition is associated with the order–disorder changes of ethylammonium cations.