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1. 3D Lead‐Organoselenide‐Halide Perovskites and their Mixed‐Chalcogenide and Mixed‐Halide Alloys

   https://doi.org/10.1002/anie.202408443  

   Li, Jiayi; Wang, Yang; Saha, Santanu; Chen, Zhihengyu; Hofmann, Jan; Misleh, Jason; Chapman, Karena W; Reimer, Jeffrey A; Filip, Marina R; Karunadasa, Hemamala I (October 2024, Angewandte Chemie International Edition)

   Abstract We incorporate Se into the 3D halide perovskite framework using the zwitterionic ligand: SeCYS (⁺NH₃(CH₂)₂Se⁻), which occupies both the X⁻and A⁺sites in the prototypical ABX₃perovskite. The new organoselenide‐halide perovskites: (SeCYS)PbX₂(X=Cl, Br) expand upon the recently discovered organosulfide‐halide perovskites. Single‐crystal X‐ray diffraction and pair distribution function analysis reveal the average structures of the organoselenide‐halide perovskites, whereas the local lead coordination environments and their distributions were probed through solid‐state⁷⁷Se and²⁰⁷Pb NMR, complemented by theoretical simulations. Density functional theory calculations illustrate that the band structures of (SeCYS)PbX₂largely resemble those of their S analogs, with similar band dispersion patterns, yet with a considerable band gap decrease. Optical absorbance measurements indeed show band gaps of 2.07 and 1.86 eV for (SeCYS)PbX₂with X=Cl and Br, respectively. We further demonstrate routes to alloying the halides (Cl, Br) and chalcogenides (S, Se) continuously tuning the band gap from 1.86 to 2.31 eV–straddling the ideal range for tandem solar cells or visible‐light photocatalysis. The comprehensive description of the average and local structures, and how they can fine‐tune the band gap and potential trap states, respectively, establishes the foundation for understanding this new perovskite family, which combines solid‐state and organo‐main‐group chemistry. 

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2. Charge-clustering induced fast ion conduction in 2LiX-GaF ₃ : A strategy for electrolyte design

   https://doi.org/10.1126/sciadv.adj9930  

   Patel, Sawankumar V.; Lacivita, Valentina; Liu, Haoyu; Truong, Erica; Jin, Yongkang; Wang, Eric; Miara, Lincoln; Kim, Ryounghee; Gwon, Hyeokjo; Zhang, Rongfu; et al (November 2023, Science Advances)

   2LiX-GaF₃(X = Cl, Br, I) electrolytes offer favorable features for solid-state batteries: mechanical pliability and high conductivities. However, understanding the origin of fast ion transport in 2LiX-GaF₃has been challenging. The ionic conductivity order of 2LiCl-GaF₃(3.20 mS/cm) > 2LiBr-GaF₃(0.84 mS/cm) > 2LiI-GaF₃(0.03 mS/cm) contradicts binary LiCl (10⁻¹²S/cm) < LiBr (10⁻¹⁰S/cm) < LiI (10⁻⁷S/cm). Using multinuclear⁷Li,⁷¹Ga,¹⁹F solid-state nuclear magnetic resonance and density functional theory simulations, we found that Ga(F,X)_npolyanions boost Li⁺-ion transport by weakening Li⁺-X⁻interactions via charge clustering. In 2LiBr-GaF₃and 2LiI-GaF₃, Ga-X coordination is reduced with decreased F participation, compared to 2LiCl-GaF₃. These insights will inform electrolyte design based on charge clustering, applicable to various ion conductors. This strategy could prove effective for producing highly conductive multivalent cation conductors such as Ca²⁺and Mg²⁺, as charge clustering of carboxylates in proteins is found to decrease their binding to Ca²⁺and Mg²⁺. 

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3. Tailoring Ion Transport in Li _3‐3y Ho _1+y Cl _6‐x Br _x via Transition‐Metal Free Structural Planes and Charge Carrier Distribution

   https://doi.org/10.1002/advs.202409668  

   Ogbolu, Bright O; Poudel, Tej P; Dikella, Thilina_N_D D; Truong, Erica; Chen, Yudan; Hou, Dewen; Li, Tianyi; Liu, Yuzi; Gabriel, Eric; Xiong, Hui; et al (February 2025, Advanced Science)

   Abstract Localized atomistic disorder in halide‐based solid electrolytes (SEs) can be leveraged to boost Li⁺mobility. In this study, Li⁺transport in structurally modified Li₃HoCl₆, via Br⁻introduction and Li⁺deficiency, is explored. The optimized Li_3‐3yHo_1+yCl_6‐xBr_xachieves an ionic conductivity of 3.8 mS cm⁻¹at 25 °C, the highest reported for holmium halide materials.^6,7Li nuclear magnetic resonance and relaxometry investigations unveil enhanced ion dynamics with bromination, attaining a Li⁺motional rate neighboring 116 MHz. X‐ray diffraction analyses reveal mixed‐anion‐induced phase transitions with disproportionate octahedral expansions and distortions, creating Ho‐free planes with favorable energetics for Li⁺migration. Bond valence site energy analysis highlights preferred Li⁺transport pathways, particularly in structural planes devoid of Ho³⁺blocking effects. Molecular dynamics simulations corroborate enhanced Li⁺diffusion with Br⁻introduction into Li₃HoCl₆. Li‐Ho electrostatic repulsions in the (001) plane presumably drive Li⁺diffusion into the Ho‐free (002) layer, enabling rapid intraplanar Li⁺motion and exchange between the 2d and 4h sites. Li_3‐3yHo_1+yCl_6‐xBr_xalso demonstrates good battery cycling stability. These findings offer valuable insights into the intricate correlations between structure and ion transport and will help guide the design of high‐performance fast ion conductors for all‐solid‐state batteries. 

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4. Ruthenium/Carbon Nanocomposites for Efficient Hydrogen Electrocatalysis: Impacts of Halide Residues

   https://doi.org/10.1002/cssc.202500802  

   Yu, Bingzhe; Liu, Qiming; Dun, Chaochao; DuBois, Davida Briana; Hou, Bryan; Pan, Dingjie; Tressel, John; Mayford, Kiley; Jones, Colton; Wang, Xiao; et al (July 2025, ChemSusChem)

   Ruthenium has emerged as a promising substitute for platinum toward the hydrogen evolution/oxidation reaction (HER/HOR). Herein, ruthenium/carbon composites are prepared by magnetic induction heating (300 A, 10 s) of RuCl₃, RuBr₃or RuI₃loaded on hollow N‐doped carbon cages (HNC). The HNC‐RuCl₃‐300A sample consists of Ru nanoparticles (dia. 1.96 nm) and abundant Cl residues. HNC‐RuBr₃‐300A possesses a larger nanoparticle size (≈19.36 nm) and lower content of Br residues. HNC‐RuI₃‐300A contains only bulk‐like Ru agglomerates with a minimal amount of I residues, due to reduced Ru‐halide bonding interactions. Among these, HNC‐RuCl₃‐300A exhibits the best HER activity in alkaline media, with a low overpotential of only −26 mV to reach 10 mA cm⁻², even outperforming Pt/C, and can be used as the cathode catalyst for anion exchange membrane water electrolyzer (along with commercial RuO₂as the anode catalyst), producing 0.5 A cm⁻²at 1.88 V for up to 100 h, a performance markedly better than that with Pt/C. HNC‐RuCl₃‐300A also exhibits the best HOR activity, with a half‐wave potential (+18 mV) even lower than that of Pt/C (+35 mV). These activities are ascribed to the combined contributions of small Ru nanoparticles and Ru‐to‐halide charge transfer that weaken H adsorption. 

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5. Diverse Coordination Geometries Derived from Trisaminocyclohexane Ligands with Appended Outer‐Sphere Hydrogen Bond Donors

   https://doi.org/10.1002/ejic.202300434  

   Ekanayake, Danushka M.; Sheridan, Patrick E.; Lindeman, Sergey V.; Fiedler, Adam T. (November 2023, European Journal of Inorganic Chemistry)

   Abstract With the aim of constructing hydrogen‐bonding networks in synthetic complexes, two new ligands derived fromcis,cis‐1,3,5‐triaminocyclohexane (TACH) have been prepared that feature pendant pyrrole or indole rings as outer‐sphere H‐bond donors. The TACH framework offers a facial arrangement of threeN‐donors, thereby mimicking common coordination motifs in the active sites of nonheme Fe and Cu enzymes. X‐ray structural characterization of a series of Cu^I‐X complexes (X=F, Cl, Br, NCS) revealed that these neutral ligands (H₃L^R, R=pyrrole or indole) coordinate in the intended facialN₃manner, yielding four‐coordinate complexes with idealizedC₃symmetry. The N−H units of the outer‐sphere heterocycles form a hydrogen‐bonding cavity around the axial (pseudo)halide ligand, as verified by crystallographic, spectroscopic, and computational analyses. Treatment of H₃L^pyrroleand H₃L^indolewith divalent transition metal chlorides (M^IICl₂, M=Fe, Cu, Zn) causes one heterocycle to deprotonate and coordinate to the M(II) center, giving rise to tetradentate ligands with two remaining outer‐sphere H‐bond donors. Further ligand deprotonation is observed upon reaction with Ni(II) and Cu(II) salts with weakly coordinating counteranions. The reported complexes highlight the versatility of TACH‐based ligands with pendant H‐bond donors, as the resulting scaffolds can support multiple protonation states, coordination geometries, and H‐bonding interactions. 

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