Inorganic Chemistry最新文献

Bi₁₂Rh₃Ag₆I₉ extendsthe Bi₁₄Rh₃I₉ family of layered bismuth-richiodides in which intermetallic topological-insulator sheets alternatewith salt-like spacer layers. High-temperature synthesis yields phase-purepowders and millimeter-sized platelets. Single-crystal X-ray diffractionreveals a rhombohedral structure composed of [Bi₁₂Rh₃I]²⁺ layers and [Ag₆I₈]^2– spacers. In this spacer, Ag⁺ cations occupy75% of the tetrahedral voids of a double iodide layer, giving riseto intrinsic two-dimensional cation disorder and mobility. Electrochemicalimpedance spectroscopy reveals a room-temperature ionic conductivityof about 10^–6 S cm^–1. Density-functionaltheory including spin–orbit coupling predicts band inversionand weak-topological-insulator invariants, while angle-resolved photoemissionspectroscopy corroborates the calculated bulk electronic structure,yielding an experimental bulk band gap of 286 meV. Transport measurementsshow strongly anisotropic, initially n-type conduction.During the initial measurement cycle, applied bias reduces the electrondoping through slow electrochemical deintercalation of silver. Afterconditioning, bulk conduction is strongly reduced; transport belowabout 130 K becomes nonactivated, the bias-induced drift ceases belowabout 50 K as Ag⁺ motion freezes, and a pronounced resistivitydrop perpendicular to the layers below 3.2 K is suggestive of a boundary-sensitivelow-dimensional transport regime. Bi₁₂Rh₃Ag₆I₉ demonstrates that spacer chemistry providesa chemical lever for carrier-density control in layered topologicalinsulators.

The mixed-cation tellurides Eu(Al_1–xGa_x)₂Te₄ (x = 0–1) were synthesizedusing two thermal profiles,resulting in subtly different structural features. Samples preparedby one-step annealing at 700 °C exhibit a composition-dependenttransformation from a body-centered orthorhombic structure with alarger cell (space group Ibam, x = 0–0.50) to a side-centered orthorhombic structure witha smaller cell (space group Cccm, x = 0.75–1.0) as the Ga content increases. Samples preparedby two-step annealing at 700 and 400 °C retain the Ibam structure throughout the entire composition range, implying thatthe Ga-richest samples such as EuGa₂Te₄ undergoa temperature-dependent structural transition, as confirmed from variable-temperaturepowder X-ray diffraction experiments. The structures consist of acommon framework of infinite linear chains of edge-sharing MTe₄ (M = Al, Ga) tetrahedrabut differ in terms of the site distribution of intervening Eu atoms.These compounds are semiconductors with narrow optical band gaps of0.6–0.9 eV. Based on calculated transport properties, theymay be suitable candidates for thermoelectric applications at hightemperatures. They undergo electrocatalysis for water splitting, butwith room for improvement in their performance.

Surfaceligands are crucial for maintaining the structural stabilityand integrity of metal nanoclusters, yet high ligand coverage oftenhinders substrate access to active metal sites. In this work, we demonstratethat an in situ generated aryl dianion ligand Py-Indole with a high coordination mode of μ₅-C,C,N-η³,η²,η¹ can significantlyreduce surface coverage and expose accessible metal sites. As a result,only six Py-Indole ligands are enough to stabilize anellipsoidal Ag₁₉ nanocluster core. The low ligand coverageon the Ag₁₉ cluster surface exposes two Ag₃ caps,which enable the binding and activation of terminal alkynes and leadto the isolation of several acetylide-bonded Ag₁₉ intermediates.Meanwhile, the basic dicarbanion sites of Py-Indole readilydeprotonate the hydroxyl group in substrates, which together withthe alkyne activation by silver atoms synergistically promote an intramolecularcyclization reaction at room temperature. The newly formed aryl dicarbanionsundergo a recurring double proton exchange process with incoming substratemolecules to sustain the catalytically active state and drive thecyclization reaction forward with aturnover number up to 320. Thesynergistic integration of low-coverage ligand architecture, polymetallicactivation, and substrate–ligand-product role-switching mechanismprovides a transformative strategy for developing highly active andstructurally resilient cluster catalysts in the future.

We studied the influenceof bridging chalcogen atoms(μ-E;E = S, Se) on the structure and reactivity of digallium dihydroxidecomplexes [{^MeLGa(OH)}₂(μ-E)] [E = S (4), Se (5); ^MeL = CH{CMe(NAr)}₂^–, Ar = 2,4,6-Me₃C₆H₂]. Compounds 4 and 5 weresynthesized from ^MeLGaCl₂ and sodium chalcogenide(Na₂E) in THF-NH₃(l), followedby controlled hydrolysis. For the sulfur system, the intermediates[{^MeLGa(Cl)}₂(μ-S)] (2) and[{^MeLGa(NH₂)}₂(μ-S)] (3) were isolated and characterized, whereas the correspondingselenium derivatives proved too reactive for isolation. The reactivityof 4 and 5 toward Group 4 metal amides,M(NR₂)₄ (M = Ti, R = Me; M = Zr, Hf, R = Et),revealed a chalcogen effect, affording both monocyclic and spirocycliccomplexes from 4, while 5 selectively yieldedspirocyclic complexes. Likewise, the milder amide Me₂Si(NMe₂)₂ reacted exclusively with 5 to producea siloxide-bridged derivative. Distinct borane-dependent pathwayswere also observed. Treatment of 4 and 5 with BH₃·THF resulted in the Ga–OH protonolysisto form cyclic borates, whereas BH₃·SMe₂ promoted hydride attack at gallium, yielding gallium hydrides. Theseresults provide an insight into the ambiphilic character of 4 and 5 and establish chalcogen bridging as astrategy for tuning their bonding and reactivity.

α-Diiminedianion ligated dialumane [L(THF)Al–Al(THF)L](1), in cooperation with Na metal, readily mediates dearomatizingC–C coupling of pyridines with high regioselectivity. Treatmentof 1 with pyridine (Py) and Na in a 1:1:1 molar ratioin toluene at room temperature afforded coupled complex [Na(THF)₆]₂[LAl–Al(L)(μ-C₁₀H₁₀N₂)Al(L)–AlL] (2), which featuresa bridging 4,4′-dihydro-4,4′-bipyridine-1,1′-diyl(C₁₀H₁₀N₂^2–) unitwhile retaining the Al(II)–Al(II) bond. However, when 4 equivof Py and 2 equiv of Na were used, the Al(II) center in 1 and Na both participated in promoting reductive coupling of Py,yielding Al(III) complex [Na(Py)₃(Et₂O)][Na⊂{LAl(μ-C₁₀H₁₀N₂)₂AlL}] (3a), which in a THF solution rearranged to a unique molecular square[Na(THF)₄]₄[{LAl(μ-C₁₀H₁₀N₂)}₄] (3b). With a relativelysmall 4-substituent on pyridine (4-Me-Py or 4-benzyl-Py), 4,4′-couplingstill occurred to form products [Na(Solv)_n]₂[LAl–Al(L)(μ-C₁₀H₈N₂R₂)Al(L)–AlL] (R = Me (4) or Bn (5)). In contrast, when the para position is equipped with a bulky group (tBu) oris incorporated within a ring (tetrahydroisoquinoline), the thermodynamicallyless favored 2,2′-coupling was observed to give mononuclearcomplexes [Na(DME)₃][LAl(NC₅H₄tBu)₂] (6) and [Na(DME)][LAl(NC₉H₁₁)₂] (7) with a chelating2,2′-dihydro-2,2′-bipyridine-1,1′-diyl ligand.Such selective C–C couplings of pyridines have not been reportedfor Al compounds before, and the regioselectivity of 4,4′-versus 2,2′-coupling is verified by DFT computations.

Photoelectrochemical (PEC) water splitting provides asustainablepathway for hydrogen production, yet achieving efficient and stablephotoanodes continues to be a formidable obstacle. Herein, a core-shellCuS@CdS-Pt photoanode is constructed via in situ hydrothermal self-assemblyfollowed by Pt surface modification. The Z-scheme heterojunction betweenCdS and CuS generates the built-in electric field (IEF), stimulatingspatial separation of photogenerated electron-hole pairs while preservingstrong redox capability. Building on this, a synergistic dual-thermaleffect is proposed and demonstrated. Specifically, the photothermaleffect of CuS enhances thermal conductivity via non-radiative relaxation-inducedphonon transport along the lattice, accelerating water oxidation kineticsand boosting charge separation efficiency. Meanwhile, the localizedsurface plasmon resonance (LSPR) effect of surface-decorated Pt strengthensthe local electromagnetic field, injects hot electrons, and providesadditional thermal energy, synergistically regulating carrier separationand transport. Consequently, the optimized CuS@CdS-Pt photoanode achievesa photocurrent density of 3.92 mA cm^–2 at 1.23 V_RHE under near-infrared (NIR) auxiliary irradiation, a Faradaicefficiency of 90.3%, and retains 90% initial photocurrent after 20h of uninterrupted running, to our knowledge exceeding all prior CdS-basedphotoanodes. This work integrates heterojunction engineering withthe dual-thermal effect, providing a new strategy for designing high-efficiency,durable photoanodes for PEC water splitting.

Zero-dimensional (0D) organic-inorganic hybrid manganese(II)halideshave attracted considerable attention for their tunable luminescenceand stimulus-responsive properties, yet simultaneously achieving high-efficiencyemission and large-hysteresis thermochromic behavior remains challenging.Herein, three 0D hybrid manganese(II) halides were constructed throughthe synergistic regulation of halide substitution and π-conjugatedcation engineering. Notably, [H(4-PipPy)]₂MnBr₄ exhibits a high photoluminescence quantum yield of 60.95% and areversible structural phase transition with a large thermal hysteresisof 94 K, among the largest values reported for 0D hybrid manganesehalides. This transition is accompanied by reversible thermochromicluminescence with an emission shift from 530 to 549 nm. Variable-temperaturephotoluminescence, differential scanning calorimetry, and variable-temperaturepowder X-ray diffraction reveal the direct relationship between structuraltransformation and luminescence switching. Moreover, the complementaryemissions of [H₂(4-PP)]MnBr₄ and [H(4-PipPy)]₂MnBr₄ enable information encryption and anti-counterfeitingapplications. This work provides new insights into the synergisticregulation of luminescence and phase transitions in zero-dimensionalhybrid manganese halides, offering a new design concept for multifunctionalthermochromic luminescent materials.

Developing chlorine-free oxidizersthat simultaneously combinehigh energy, low mechanical sensitivity, and moisture resistance remainsa major challenge for dinitramide-based energetic materials. Herein,two nitrogen-rich heterocyclic dinitramide salts, 3 and 6, were preparedthrough aqueous metathesis to investigate the influence of cationstructure on their physicochemical and energetic properties. Compound3 shows a decomposition onset temperature of 170 °C and a stepwiseexothermic decomposition process, indicating relatively high thermalrobustness. In contrast, compound 6 combines a measured density of1.83 g cm^–3 with a calculated detonation velocityof 8951 m s^–1 and a detonation pressure of 35.9GPa, comparable to those of RDX. No initiation was observed for eithersalt up to the maximum tested impact energy and friction load of 40J and 360 N, respectively. Compound 6 also exhibits minimal moistureuptake after exposure to 55% relative humidity at 25 °C for 54h. EXPLO5 calculations predict maximum specific impulses of 268.6and 270.0 s for GAP- and NEPE-based formulations containing 45 and65 wt % compound 6, respectively. These results demonstrate that nitrogen-richheterocyclic cations provide an effective strategy for balancing theenergetic performance, mechanical safety, and moisture resistanceof dinitramide-based materials.

Developingrobust, sustainable molecular photosensitizers thatcombine strong visible-light absorption, long excited-state lifetimes,and potent redox reactivity remains a fundamental challenge in photoredoxcatalysis. Cu(I) complexes are promising earth-abundant alternativesto precious-metal photocatalysts, motivating fundamental investigationsinto their excited-state properties and photocatalytic reactivity.Here we report a new class of heteroleptic four-coordinate Cu(I) complexessupported by chelating diisocyanide ligands, one with a m-terphenyl (CNAr₃NC) core and an analogue with a m-quinquephenyl core (CNAr₅NC), in combinationwith a β-diketiminate ligand with 2,6-dimethylphenyl N-substituents (dmp-NacNac). With more sterically encumberedor electron-rich β-diketiminate ligands, diisocyanide-bridged,three-coordinate dicopper complexes are formed instead. The four-coordinatecomplex supported by the quinquephenyl-based diisocyanide CNAr₅NC, Cu2, exhibits strong visible absorption,an excited-state lifetime over twice as long as the m-terphenyl CNAr₃NC analogue (103 ns vs 48 ns), and a highlyreducing excited-state oxidation potential (*E^ox = −2.4 V vs Fc^+/0). As a result, Cu2 is active for visible-light photocatalytic E/Z isomerization of stilbene and reductive photoredoxtransformations of substituted benzophenone derivatives. In the latterapplication, Cu2 outperforms a related three-coordinatemonoisocyanide-terminated analogue, affording higher yields of photohydrogenationand hydrodehalogenation products with lower catalyst loadings.