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Designing ultrathin transition metal electrocatalysts with optimal surface chemistry state is crucial for oxygen evolution reaction (OER). However, the structure‐dependent electrochemical performance and the underlying catalytic mechanisms are still not clearly distinguished. Herein, we synthesize ultrathin Co6.8Se8 nanosheets (NSs) with subnanometer thickness by incorporating catalytically inactive selenium (Se) into ultrathin Co(OH)2, thereby switching the OER reaction pathway from adsorbate evolution mechanism (AEM) to oxide path mechanism (OPM). The prepared ultrathin Co6.8Se8 NSs exhibit an overpotential of 253 mV at 10 mA/cm2, outperforming the mostly reported Co‐based electrocatalysts. Advanced operando synchrotron spectroscopies and X‐ray absorption spectroscopy reveal the ultrathin Co6.8Se8 NSs, whose surface is reconstructed into Se‐doped Co(OH)2 during the OER process, could trigger direct O*−O* radical coupling rather than OOH* intermediates within AEM pathway thus lowering the energy input. Density functional theory calculations confirm that Co6.8Se8 NSs with shorter Co−Co bond length and stable Co−Se bond could optimize the rate‐determining step barrier via OPM pathway. Besides, rechargeable zinc‐air batteries based on Co6.8Se8 NSs exhibit excellent stability for more than 500 h of continuous charge–discharge cycles at 4 mA/cm2. The present study highlights the structural‐dependent switch of OER pathways and provides valuable insights for further development of ultrathin OER catalysts. [ABSTRACT FROM AUTHOR]

A number of quinoidal molecules with symmetric end‐capping groups, particularly dicyanomethylene units, have been synthesized for organic optoelectronic materials. In comparison, dissymmetric quinoidal molecules, characterized by end‐capping with different groups, are less explored. In this paper, we present the unexpected formation of new formal quinoidal molecules, which are end‐capped with both dicyanomethylene and triphenylphosphonium moieties. The structures of these dissymmetric quinoidal molecules were firmly verified by single crystal structural analyses. On the basis of the control experiments and DFT calculations, we proposed the reaction mechanism for the formation of these dissymmetric quinoidal molecules. The respective zwitterionic forms should make contributions to the ground state structures of these quinoidal molecules based on the analysis of their bond lengths and aromaticity and Mayer Bond Orbital (MBO) calculation. This agrees well with the fact that negative solvatochromism was observed for these quinoidal molecules. Although these new quinoidal molecules are non‐emissive both in solutions and crystalline states, they become emissive with quantum yields up to 51.4 % after elevating the solvent viscosity or dispersing them in a PMMA matrix. Interestingly, their emissions can also be switched on upon binding with certain proteins, in particular with human serum albumin. [ABSTRACT FROM AUTHOR]

MnO2 is commonly used as the cathode material for aqueous zinc‐ion batteries (AZIBs). The strong Coulombic interaction between Zn ions and the MnO2 lattice causes significant lattice distortion and, combined with the Jahn–Teller effect, results in Mn2+ dissolution and structural collapse. While proton intercalation can reduce lattice distortion, it changes the electrolyte pH, producing chemically inert byproducts. These issues greatly affect the reversibility of Zn2+ intercalation/extraction, leading to significant capacity degradation of MnO2. Herein, we propose a novel method to enhance the cycling stability of δ‐MnO2 through selenium doping (Se−MnO2). Our work indicates that varying the selenium doping content can regulate the intercalation ratio of H+ in MnO2, thereby suppressing the formation of ZnMn2O4 by‐products. Se doping mitigates the lattice strain of MnO2 during Zn2+ intercalation/deintercalation by reducing Mn−O octahedral distortion, modifying Mn−O bond length upon Zn2+ insertion, and alleviating Mn dissolution caused by the Jahn–Teller effect. The optimized Se−MnO2 (Se concentration of 0.8 at.%) deposited on carbon nanotube demonstrates a notable capacity of 386 mAh g−1 at 0.1 A g−1, with exceptional long‐term cycle stability, retaining 102 mAh g−1 capacity after 5000 cycles at 3.0 A g−1. [ABSTRACT FROM AUTHOR]

Graphene‐like molecules with multiple zigzag edges are emerging as promising gain materials for organic lasers. Their emission wavelengths can vary widely, ranging from visible to near‐infrared (NIR), as the molecular size increases. Specifically, rhombus‐shaped molecular graphenes with two pairs of parallel zigzag edges, known as [n]rhombenes, are excellent candidates for NIR lasers due to their small energy gaps. However, synthesizing large‐size rhombenes with emission beyond 800 nm in solution remains a significant challenge. In this study, we present a straightforward synthesis of an aryl‐substituted [4]rhombene derivative, [4]RB‐Ar, using a method that combines intramolecular radical‐radical coupling with Bi(OTf)3‐mediated cyclization of vinyl ethers. The structure of [4]RB‐Ar was confirmed through X‐ray crystallographic analysis. Bond length analysis and theoretical calculations indicate that aromatic sextets are predominantly localized along the molecule's long axis. Significantly, [4]RB‐Ar demonstrates narrow amplified spontaneous emission at around 834 nm when dispersed in polystyrene thin films. Moreover, solution‐processed distributed feedback lasers employing [4]RB‐Ar as the active gain material display tunable narrow emissions in the range of 830 to 844 nm. [ABSTRACT FROM AUTHOR]

Developing ionic copper‐iodine clusters with multiple emitting is crucial for enriching lighting and display materials with various colors. However, the luminescent properties of traditional ionic copper‐iodine clusters are often closely associated with low‐energy cluster‐centered triplet emission, which will redshift further as the Cu⋅⋅⋅Cu bond length decreases. This article utilizes a pressure‐treated strategy to achieve an anomalous pressure‐induced blue‐shifted luminescence phenomenon in ionic Cu4I6(4‐dimethylamino‐1‐ethylpyridinium)2 crystals for the first time, which is based on dominant through‐space charge‐transfer (TSCT). Herein, we reveal that the more advantageous through‐space interactions in the competition between cuprophilic interactions and through‐space interactions can lead to a blue‐shifted luminescence. High‐pressure angle‐dispersive X‐ray diffraction and high‐pressure infrared experiments show that the enhanced through‐space interactions mainly originate from forming new intermolecular C−H⋅⋅⋅I hydrogen bonds and the enhancement of van der Waals interactions between organic cations and anionic clusters. Theoretical calculations and experimental studies of excited‐state dynamics confirm that the blue‐shifted emission is due to the increased energy gap between the excited triplet and ground states caused by the electron delocalization under stronger through‐space interactions. This work deepens previous understanding and provides a new avenue to design and synthetic ionic copper‐iodine clusters with high‐energy TSCT emission. [ABSTRACT FROM AUTHOR]

Regulating competitive reaction pathways to direct the selectivity of electrochemical CO2 reduction reaction toward a desired product is crucial but remains challenging. Herein, switching product from HCOOH to CO is achieved by incorporating Sb element into the CuS, in which the Cu−S ionic bond is coupled with S−Sb covalent bond through bridging S atoms that elongates the Cu−S bond from 2.24 Å to 2.30 Å. Consequently, CuS with a shorter Cu−S bond exhibited a high selectivity for producing HCOOH, with a maximum Faradaic efficiency (FE) of 72 %. Conversely, Cu3SbS4 characterized by an elongated Cu−S bond exhibited the most pronounced production of CO with a maximum FE of 60 %. In situ spectroscopy combined with density functional theory calculations revealed that the altered Cu−S bond length and local coordination environment make the *HCOO binding energy weaker on Cu3SbS4 compared to that on CuS. Notably, a volcano‐shaped correlation between the Cu−S bond length and adsorption strength of *COOH indicates that Cu−S in Cu3SbS4 as double‐active sites facilitates the adsorption of *COOH, and thus results in the high selectivity of Cu3SbS4 toward CO. [ABSTRACT FROM AUTHOR]

AgGaS2 (AGS) is the most commonly used commercial infrared nonlinear optical (IR NLO) material. However, AGS has a narrow band gap (Eg=2.58 eV) and a low laser‐induced damage threshold (LIDT), primarily attributed to its mobile liquid‐like Ag+ constituent and the unstable Ag−S chemical bond. Herein, we propose a “band reformation of AGS” strategy, which leads to the successful syntheses of four lanthanide sulfides, LiLnGeS4 (Ln=La−Nd), crystalizing in an asymmetric Ama2 structure. LiLaGeS4 demonstrates that eliminating the presence of Ag‐4d band increases the Eg to 3.32 eV and enhances the LIDT (14–29×AGS, measured by both powder and single crystal); while increasing the nonbonding density of states of the S‐3p band enhances the 2nd‐nonlinear optical coefficient (1.06×AGS). Besides, the bond length discrepancy between [LiS4], [GeS4] and [LaS8] units leads to a moderate birefringence (Δn=0.052). Such a unique structure further results in extremely small thermal expansion with αL=0.41–1.74×10−5 K−1, along different crystallographic axes. Our theoretical studies indicate that the synergy of the structure building units contribute to the second harmonic generation performance. These results suggest that the “band reformation of AGS” strategy provides effective guidance to discover new NLO crystals with optimized performance. [ABSTRACT FROM AUTHOR]

According to the principles of chemical thermodynamics, the catalytic activation of small molecules (like N2 in air and CO2 in flue gas) generally exhibits a negative activity dependence on O2 owning to the competitive oxygen reduction reaction (ORR). Nevertheless, some catalysts can show positive activity dependence for N2 electrofixation, an important route to produce ammonia under ambient condition. Here we report that the positive activity dependence on O2 of (Ni0.20Co0.20Fe0.20Mn0.19Mo0.21)3S4 catalyst arises from high‐entropy mechanism. Through experimental and theoretical studies, we demonstrate that under the reaction condition in the mixed N2/O2, the adsorption of O2 on high‐entropy catalyst contributes to activating N2 molecules characteristic of elongated N≡N bond lengths. As comparison to the low‐ and medium‐entropy counterparts, high entropy can play the second role of attenuating competitive ORR by displaying a negative exponential entropy‐ORR activity relationship. Accordingly, benefiting from the O2, the system for direct air electrofixation has demonstrated an ammonia yield rate of 47.70 μg h−1 cm−2, which is even 1.5 times of pure N2 feedstock (31.92 μg h−1 cm−2), overtaking all previous reports for this reaction. We expect the present finding providing an additional dimension to high entropy that leverages systems beyond the constraint of traditional rules. [ABSTRACT FROM AUTHOR]

Targeted synthesis of acetic acid (CH3COOH) from CO2 photoreduction under mild conditions mainly limits by the kinetic challenge of the C−C coupling. Herein, we utilized doping engineering to build charge‐asymmetrical metal pair sites for boosted C−C coupling, enhancing the activity and selectivity of CO2 photoreduction towards CH3COOH. As a prototype, the Pd doped Co3O4 atomic layers are synthesized, where the established charge‐asymmetrical cobalt pair sites are verified by X‐ray photoelectron spectroscopy and X‐ray absorption near edge spectroscopy spectra. Theoretical calculations not only reveal the charge‐asymmetrical cobalt pair sites caused by Pd atom doping, but also manifest the promoted C−C coupling of double *COOH intermediates through shortening of the coupled C−C bond distance from 1.54 to 1.52 Å and lowering their formation energy barrier from 0.77 to 0.33 eV. Importantly, the decreased reaction energy barrier from the protonation of two*COOH into *CO intermediates for the Pd‐Co3O4 atomic layer slab is 0.49 eV, higher than that of the Co3O4 atomic layer slab (0.41 eV). Therefore, the Pd‐Co3O4 atomic layers exhibit the CH3COOH evolution rate of ca. 13.8 μmol g−1 h−1 with near 100% selectivity, both of which outperform all previously reported single photocatalysts for CO2 photoreduction towards CH3COOH under similar conditions. [ABSTRACT FROM AUTHOR]

Targeted synthesis of acetic acid (CH3COOH) from CO2 photoreduction under mild conditions mainly limits by the kinetic challenge of the C−C coupling. Herein, we utilized doping engineering to build charge‐asymmetrical metal pair sites for boosted C−C coupling, enhancing the activity and selectivity of CO2 photoreduction towards CH3COOH. As a prototype, the Pd doped Co3O4 atomic layers are synthesized, where the established charge‐asymmetrical cobalt pair sites are verified by X‐ray photoelectron spectroscopy and X‐ray absorption near edge spectroscopy spectra. Theoretical calculations not only reveal the charge‐asymmetrical cobalt pair sites caused by Pd atom doping, but also manifest the promoted C−C coupling of double *COOH intermediates through shortening of the coupled C−C bond distance from 1.54 to 1.52 Å and lowering their formation energy barrier from 0.77 to 0.33 eV. Importantly, the decreased reaction energy barrier from the protonation of two*COOH into *CO intermediates for the Pd‐Co3O4 atomic layer slab is 0.49 eV, higher than that of the Co3O4 atomic layer slab (0.41 eV). Therefore, the Pd‐Co3O4 atomic layers exhibit the CH3COOH evolution rate of ca. 13.8 μmol g−1 h−1 with near 100% selectivity, both of which outperform all previously reported single photocatalysts for CO2 photoreduction towards CH3COOH under similar conditions. [ABSTRACT FROM AUTHOR]

Nitrogen‐doped, carbon‐supported transition metal catalysts are excellent for several reactions. Structural engineering of M−Nx sites to boost catalytic activity is rarely studied. Here, we demonstrate that the structural flexibility of Fe−N3 site is vital for tuning the electronic structure of Fe atoms and regulating the catalytic transfer hydrogenation (CTH) activity. By introducing carbon defects, we construct Fe−N3 sites with varying Fe−N bond lengths distinguishable by X‐ray absorption spectroscopy. We investigate the CTH activity by density‐functional theory and microkinetic calculations and reveal that the vertical displacement of the Fe atom out of the plane of the support, induced by the Fe−N3 distortion, raises the Fe 3dz2 ${3{d}_{{z}^{2}}{\rm \ }}$ orbital and strengthens binding. We propose that the activity is controlled by the relaxation of the reconstructed site, which is further affected by Fe−N bond length, an excellent activity descriptor. We elucidate the origin of the CTH activity and principles for high‐performing Fe−N−C catalysts by defect engineering. [ABSTRACT FROM AUTHOR]

The discovery of compounds with low thermal conductivity and the understanding of their microscopic mechanisms are of great challenges and scientific significance. Herein, we report a unique ternary sulfide compound, Cu3BiS3, in which all Cu atoms are coordinated within a two‐dimensional [CuS3] triangle plane. This local coordination leads to efficient out‐of‐plane phonon scattering and an ultralow thermal conductivity. Through DFT phonon spectrum calculations and analyses, we reveal that the lowest vibration frequency decreases from 2 THz for high‐dimensional [CuS4] tetrahedral coordinated Cu atoms in CuBiS2 (CN=4, with an average Cu−S bond length of 2.328 Å) to 1.5 THz for low‐dimensional [CuS3] triangular coordinated Cu atoms in Cu3BiS3 (CN=3, with a shorter Cu−S bond length of 2.285 Å). This is due to the out‐of‐plane thermal vibration of the Cu atoms in the latter. Consequently,Cu3BiS3 exhibits one of the lowest values of κlat (0.32 W/m K) among its peer, with a 36 % reduction compared to CuBiS2 (0.50 W/m K). This groundbreaking discovery highlights the significant role of 2D local coordination in reducing thermal conductivity through characteristic out‐of‐plane phonon scattering, while also contributing to a large Grüneisen parameter (2.06) in Cu3BiS3. [ABSTRACT FROM AUTHOR]

Increasing the chemical diversity of organic semiconductors is essential to develop efficient electronic devices. In particular, the replacement of carbon‐carbon (C−C) bonds with isoelectronic boron‐nitrogen (B−N) bonds allows precise modulation of the electronic properties of semiconductors without significant structural changes. Although some researchers have reported the preparation of B2N2 anthracene derivatives with two B−N bonds, no compounds with continuous multiple BN units have been prepared yet. Herein, we report the synthesis and characterization of a B2N2 anthracene derivative with a BNBN unit formed by converting the BOBN unit at the zigzag edge. Compared to the all‐carbon analogue 2‐phenylanthracene, BNBN anthracene exhibits significant variations in the C−C bond length and a larger highest occupied molecular orbital–lowest unoccupied molecular orbital energy gap. The experimentally determined bond lengths and electronic properties of BNBN anthracene are confirmed through theoretical calculations. The BOBN anthracene organic light‐emitting diode, used as a blue host, exhibits a low driving voltage. The findings of this study may facilitate the development of larger acenes with multiple BN units and potential applications in organic electronics. [ABSTRACT FROM AUTHOR]

We report the synthesis and characterization of the nickelocenium cations [NiCp2]⋅+ and [NiCp2]2+ as their [F‐{Al(ORF)3}2]− (Cp = C5H5; RF=C(CF3)3) salts. Diamagnetic [NiCp2]2+ represents the first example for the isolation of an unsubstituted parent metallocene dication. Both salts were generated by reacting neutral NiCp2 with [NO]+[F‐{Al(ORF)3}2]− in 1,2,3,4‐tetrafluorobenzene (4FB). The salts were characterized by single crystal X‐ray diffraction (XRD), indicating shorter metal‐ligand bond lengths for the higher charged salt. Powder XRD shows the salts to be phase pure, cyclic voltammetry in 4FB gave quasi reversible redox waves at −0.44 (0→1) and +1.17 V (1→2) vs Fc/Fc+. The 1H NMR of [NiCp2]2+ is a singlet at 8.6 ppm, whereas paramagnetic [NiCp2]⋅+ is significantly shifted upfield to −103.1 ppm. [ABSTRACT FROM AUTHOR]

Despite the intriguing potential shown by Sn‐based perovskite oxides in CO2 electroreduction (CO2RR), the rational optimization of their CO2RR properties is still lacking. Here we report an effective strategy to promote CO2‐to‐HCOOH conversion of Sn‐based perovskite oxides by A‐site‐radius‐controlled Sn−O bond lengths. For the proof‐of‐concept examples of Ba1−xSrxSnO3, as the A‐site cation average radii decrease from 1.61 to 1.44 Å, their Sn−O bonds are precisely shortened from 2.06 to 2.02 Å. Our CO2RR measurements show that the activity and selectivity of these samples for HCOOH production exhibit volcano‐type trends with the Sn−O bond lengths. Among these samples, the Ba0.5Sr0.5SnO3 features the optimal activity (753.6 mA ⋅ cm−2) and selectivity (90.9 %) for HCOOH, better than those of the reported Sn‐based oxides. Such optimized CO2RR properties could be attributed to favorable merits conferred by the precisely controlled Sn−O bond lengths, e.g., the regulated band center, modulated adsorption/activation of intermediates, and reduced energy barrier for *OCHO formation. This work brings a new avenue for rational design of advanced Sn‐based perovskite oxides toward CO2RR. [ABSTRACT FROM AUTHOR]

Photoexcited molecular trajectories on potential energy surfaces (PESs) prior to thermalization are intimately connected to the photochemical reaction outcome. The excited‐state trajectories of a diplatinum complex featuring photo‐activated metal–metal σ‐bond formation and associated Pt−Pt stretching motions were detected in real time using femtosecond wide‐angle X‐ray solution scattering. The observed motions correspond well with coherent vibrational wavepacket motions detected by femtosecond optical transient absorption. Two key coordinates for intersystem crossing have been identified, the Pt−Pt bond length and the orientation of the ligands coordinated with the platinum centers, along which the excited‐state trajectories can be projected onto the calculated PESs of the excited states. This investigation has gleaned novel insight into electronic transitions occurring on the time scales of vibrational motions measured in real time, revealing ultrafast nonadiabatic or non‐equilibrium processes along excited‐state trajectories involving multiple excited‐state PESs. [ABSTRACT FROM AUTHOR]

The slow water dissociation process in alkaline electrolyte severely limits the kinetics of HER. The orientation of H2O is well known to affect the dissociation process, but H2O orientation is hard to control because of its random distribution. Herein, an atomically asymmetric local electric field was designed by IrRu dizygotic single‐atom sites (IrRu DSACs) to tune the H2O adsorption configuration and orientation, thus optimizing its dissociation process. The electric field intensity of IrRu DSACs is over 4.00×1010 N/C. The ab initio molecular dynamics simulations combined with in situ Raman spectroscopy analysis on the adsorption behavior of H2O show that the M−H bond length (M=active site) is shortened at the interface due to the strong local electric field gradient and the optimized water orientation promotes the dissociation process of interfacial water. This work provides a new way to explore the role of single atomic sites in alkaline hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

The location of Brønsted‐acid sites (bridging OH groups, b‐OH) at different crystallographic positions of zeolite catalysts influences their reactivity due to varying confinement. Selecting the most stable b‐OH conformers at each of the 12 T‐sites (T=Si/Al) of H‐MFI, a representative set of 26 conformers is obtained which includes free b‐OH groups pointing into the empty pore space and b‐OH groups forming H‐bonds across five‐ or six‐membered rings of TO4 tetrahedra. Chemically accurate coupled‐cluster‐quality calculations for periodic models show that the strength of internal H‐bonds and, hence, the OH bond length vary substantially with the framework position. For 11 of the 19 H‐bonded b‐OH groups examined, our predictions fall into the full width at half maximum range of the experimental signals at 3250±175 cm−1 and 7.0±1.4 ppm which supports previously debated assignments of these signals to H‐bonded b‐OH sites. [ABSTRACT FROM AUTHOR]

Circumcoronene, a hexagonal graphene fragment with six zigzag edges, has been the focus of theoretical studies for many years, but its synthesis in solution has remained a challenge. In this study, we present a facile method for synthesizing three derivatives of circumcoronene using Brønsted/Lewis acid‐mediated cyclization of vinyl ether or alkyne. Their structures were confirmed through X‐ray crystallographic analysis. Bond length analysis, NMR measurement, and theoretical calculations showed that circumcoronene mostly follows Clar's bonding model and exhibits dominant local aromaticity. Its absorption and emission spectra are similar to those of the smaller hexagonal coronene due to its six‐fold symmetry. [ABSTRACT FROM AUTHOR]

Nonlinear optical (NLO) switch materials that turn on/off second‐harmonic generation (SHG) at a phase transition temperature (Tc) are promising for applications in the fields of photoswitching and optical computing. However, precise control of Tc remains challenging, mainly because a linearly tunable Tc has not been reported to date. Herein, we report a unique selenate, tetragonal P4‾ ${\bar{4}}$ 21c [Ag(NH3)2]2SeO4 with a=b=8.5569(2) Å and c=6.5208(2) Å that exhibits a strong SHG intensity (1.3×KDP) and a large birefringence (Δnobv.=0.08). This compound forms a series of isostructural solid‐solution crystals [Ag(NH3)2]2SxSe1−xO4 (x=0–1.00) that exhibit excellent NLO switching performance and an unprecedented linearly tunable Tc,x,exp.=T0-kx ${{T}_{\left(c,{\rm \ }x\right),{\rm \ }\left({\rm e}{\rm x}{\rm p}.\right)}{\rm \ }={T}_{0}-kx}$ spanning 430 to 356 K. The breaking of localized hydrogen bonds between SeO42− and the cation triggers a phase transition accompanied by hydrogen bond length changes with increasing x and a linear change in the enthalpy ΔHx=ΔU1-ΔU2x+ΔU2 ${{{\rm { \Delta{}}}H}_{x}=\left({\rm { \Delta{}}}{U}_{1}-{\rm { \Delta{}}}{U}_{2}\right)x+{\rm { \Delta{}}}{U}_{2}}$. [ABSTRACT FROM AUTHOR]

We report here the synthesis and structural characterization of the first binary iron arsenide cluster anion, [Fe3(As3)3(As4)]3−, present in both [K([2.2.2]crypt)]3[Fe3(As3)3(As4)] (1) and [K(18‐crown‐6)]3[Fe3(As3)3(As4)]⋅en (2). The cluster contains an Fe3 triangle with three short Fe−Fe bond lengths (2.494(1) Å, 2.459(1) Å and 2.668(2) Å for 1, 2.471(1) Å, 2.473(1) Å and 2.660(1) Å for 2), bridged by a 2‐butene‐like As4 unit. An analysis of the electronic structure using DFT reveals a triplet ground state with direct Fe−Fe bonds stabilizing the Fe3 core. [ABSTRACT FROM AUTHOR]

In order to better understand the effect of non‐covalent weak interactions on molecules, we have explored a variety of weak interactions, such as improper H‐bonding (HB), tetrel bonds (TBs) and halogen bonds, in fluorinated chiral zinc complexes. High resolution neutron diffraction studies revealed a methylene carbon‐hydrogen bond elongation and shortening due to TB and improper HB interactions, respectively. To show the accumulative effects of multiple weak interactions on the C−H bond, three types of tetrel bonds have been carefully examined. We have also shown how C−H bond elongation can be easily offset by forming an improper HB with the H atom from this C−H bond. Non‐covalent interaction and electrostatic potential analysis investigations have been used to affirm the nature of the interactions based on density functional theory (DFT) and other related calculations. [ABSTRACT FROM AUTHOR]

The synergistic effect of bimetallic heterogeneous catalysis in the reaction of nitrate reduction to nitrogen has been widely discussed, but it is still not clear how this effect works at the atomic scale, hindering the rational design of high‐performance catalysts. Here, for the first time, 2D phosphorene was used as a giant P ligand to confine high‐density PdCu dual‐atom to form a unique PdCuP4 coordination structure, and this catalyst achieves 96.3 % NO3− removal rate and 95.2 % N2 selectivity. In situ characterization combined with density functional theory (DFT) calculations show that the PdCu dual‐atom form covalent‐like bonds with adjacent P atoms, reducing the adsorption energy of the reactants. The synergistic effect of PdCu dual‐atom promotes the breaking of N−O bond, and the short bond length of ≈3 Å between PdCu atoms accelerates the transfer of NO2−, and eventually the two Pd−N adjacent to the surface of Pd rapidly combine to form N2. [ABSTRACT FROM AUTHOR]

An [8]cyclo‐para‐phenylmethine derivative ([8]CPPM‐Mes) was synthesized. X‐ray analysis revealed a tub‐shaped geometry similar to the cyclooctatetraene, with alternating benzenoid/quinoid structure. Variable‐temperature NMR measurements disclosed a slow valence tautomerization process with an interconversion energy barrier of about 11.7 kcal mol−1 at coalescence temperature (273 K), and two more lower‐barrier dynamic processes involving flipping of the 1,4‐phenyl rings on the backbone and rotation of the mesityl substituents. Its dication ([8]CPPM‐Mes2+) adopts a bowl‐like geometry with a smaller depth of the cavity, and a slow bowl inversion process was observed by dynamic NMR. The bond lengths of the benzenoid/quinoid rings are more averaged via electron delocalization and the molecule shows global aromaticity, which was further validated by NMR and theoretical analysis. [8]CPPM‐Mes2+ exhibits open‐shell diradical character with a small singlet‐triplet energy gap (−1.8 kcal mol−1). [ABSTRACT FROM AUTHOR]

A dinuclear hafnium complex containing the parent imido ligand [(PN)(PNC)Hf=NH{μ2‐K}]2 (2) (PN−=(N‐(2‐PiPr2‐4‐methylphenyl)‐2,4,6‐Me3C6H2; PNC2−=(N‐(2‐PiPr2‐4‐methylphenyl)‐2,4,6‐CH2Me2C6H2), was prepared by reduction of the bisazide trans‐[(PN)2Hf(N3)2] (1) with two equiv of KC8. Encapsulation of K+ in 2 with crown‐ether or cryptand affords the first discrete salt [K(encap)][(PN)(PNC)Hf≡NH] (encap=18‐crown‐6(THF)2, 3; 2,2,2‐Kryptofix, 4), featuring a terminal parent imide and possessing some of the shortest Hf−N bond lengths known to date. DFT calculations revealed formation of 2 to proceed via an extremely basic monomeric nitrido, [(PN)2Hf≡N]−(A), having a computed pKBH+ of ∼57 followed by heterolytic splitting of an inert 1,2‐CH bond of a benzylic methyl group across the Hf≡N triple bond in A. An electronic structure analysis reveals A to possess a covalent Hf≡N triple bond and of super‐basic character. We also showcase reactivity of the Hf≡NH bond with various electrophiles. [ABSTRACT FROM AUTHOR]

Synthesis of triangulene and its derivatives is challenging due to their intrinsic high spin nature. Herein, we report solution‐phase synthesis and isolation of a nitrogen‐doped triangulene (i.e. aza‐triangulene) (NT) and its cation (NT+) in single‐crystal form. Notably, the cation NT+ can be regarded as an isoelectronic structure of the corresponding all‐carbon triangulene. Both NT and NT+ show reasonable stability due to kinetic blocking by bulky and electron‐withdrawing aryl substituents, and intramolecular donor‐acceptor interaction. Bond length analysis, magnetic measurements and theoretical calculations reveal that the neutral NT has a doublet ground state with a zwitterionic character, while the cation NT+ exhibits a triplet ground state with a singlet‐triplet energy gap of +0.84 kcal mol−1. This study provides a rational strategy to access high‐spin systems by heteroatom doping of pure π‐conjugated polycyclic hydrocarbons. [ABSTRACT FROM AUTHOR]

Single‐atom active‐site catalysts have attracted significant attention in the field of photocatalytic CO2 conversion. However, designing active sites for CO2 reduction and H2O oxidation simultaneously on a photocatalyst and combining the corresponding half‐reaction in a photocatalytic system is still difficult. Here, we synthesized a bimetallic single‐atom active‐site photocatalyst with two compatible active centers of Mn and Co on carbon nitride (Mn1Co1/CN). Our experimental results and density functional theory calculations showed that the active center of Mn promotes H2O oxidation by accumulating photogenerated holes. In addition, the active center of Co promotes CO2 activation by increasing the bond length and bond angle of CO2 molecules. Benefiting from the synergistic effect of the atomic active centers, the synthesized Mn1Co1/CN exhibited a CO production rate of 47 μmol g−1 h−1, which is significantly higher than that of the corresponding single‐metal active‐site photocatalyst. [ABSTRACT FROM AUTHOR]

Many chemicals known today are partially or fully aromatic, since a ring framework experiences additional stabilization through the delocalization of π‐electrons. While aromatic rings with equal numbers of π‐electrons and ring atoms such as benzene are particularly stable, those with the minimally required two π‐electrons are very rare and yet remain limited to three‐ and four‐membered rings if not stabilized in the coordination sphere of heavy metals. Here we report the facile synthesis of a dipotassium cyclopentagallene, a unique example of a five‐membered aromatic ring stabilized by only two π‐electrons. Single‐crystal X‐ray diffraction revealed a planar Ga5 ring with almost equal gallium–gallium bond lengths, which together with computational and spectroscopic data confirm its aromatic character. Our results prove that aromatic stabilization goes far beyond what has previously been assumed as minimum π‐electron count in a five‐atom ring fragment. [ABSTRACT FROM AUTHOR]

The crystal structures of [NH3F]+[CF3SO3]−, [NH2F2]+[SbF6]−, and [N2F3]+[Sb3F16]− have been determined, representing the first structural characterizations of these simple fluoro‐nitrogen cations. The influences of the hybridization of the central nitrogen atom and of the number of fluorine substituents on the N−F bond lengths are evaluated for the series N2F+, N2F3+, NF2O+, NH3F+, NH2F2+, and NF4+. It is shown that the N−F bond length decreases from 1.40 Å to 1.26 Å with increasing fluorine substitution and increasing s‐character of the nitrogen atom, and that unusual N−F bond lengths reported in the previous literature are caused by disorder problems [ABSTRACT FROM AUTHOR]

We propose self‐expanding lithium‐ion transport channels to construct a fast‐charging anode and realize high‐performance fast‐charging Li‐ion batteries. The self‐expanded Li‐ion transport channels can be enabled by a self‐reversible conversion of chemical bonds with different bond lengths in the anode driven by the interactions with Li ions during cycling, reduce the energy barrier of Li‐ion transport and allow a fast Li‐ion solid‐state diffusion, whereby the severe voltage polarization and Li metal plating are effectively eliminated. Our proof‐of‐concept demonstration of the self‐reversible conversion of chemical bonds on the surface of graphdiyne successfully verifies the self‐expanded Li‐ion transport channels, self‐accelerated Li in‐plane/out‐of‐plane migration, and superior fast‐charging capability with a high capacity (342 mA h g−1) and an ultra‐long lifespan (22 000 cycles) under extremely fast‐charging conditions (6 C rate, 1 C=744 mA g−1), even at low temperatures (−10 °C). [ABSTRACT FROM AUTHOR]

While research into deep eutectic solvents (DESs) has expanded over the previous two decades, the focus has remained on the utilization of hydrogen bond donors in these systems. Additionally, the majority of the known DESs rely on at least one ionic component. Through the combination of 1,3‐dithiane and 1,2‐diiodo‐3,4,5,6‐tetrafluorobenzene (1,2‐F4DIB), we report the first known DES based on halogen bonding. This mixture remains a liquid, with a eutectic melting temperature of 13.7 °C over a range of 1,3‐dithiane mole fraction (0.35 to 0.75). Additionally, cocrystals of 1,3‐ and 1,4‐dithiane with 1,2‐, 1,3‐, and 1,4‐F4DIB, as well as 1,3,5‐trifluoro‐2,4,6‐triiodobenzene were studied via single‐crystal X‐ray diffraction. These data reveal a wide range of halogen bonding strengths (0.85

The synthesis and characterization of the bis(η6‐benzene)lithium cation, the benzene metallocene of the lightest metal, is reported. The boron compound FmesBCl2 [Fmes: 2,4,6‐tris(trifluoromethyl)phenyl] reacted with three molar equivalents of the lithio‐acetylene reagent Li‐C≡C‐Fmxyl [Fmxyl: 3,5‐bis(trifluoromethyl)phenyl]. Subsequent crystallization from benzene gave the [bis(η6‐benzene)Li]+ cation with the [{FmesB(‐C≡C‐Fmxyl)3}2Li]− anion. This parent [(arene)2Li]+ cation shows an eclipsed arrangement of the pair of benzene ligands at the central lithium cation with uniform carbon‐lithium bond lengths. The corresponding [(η6‐toluene)2Li]+ and [(η6‐durene)2Li]+ containing salts were similarly prepared. The bis(arene)lithium cations were characterized by X‐ray diffraction, by solid‐state 7Li MAS NMR spectroscopy and their bonding features were analyzed by DFT calculations. [ABSTRACT FROM AUTHOR]

The synthesis of phenalenyl‐endcapped [5]cumulene as a cumulene‐based singlet biradical and the spin correlation changes of one‐dimensional aggregates are described. The high propensity for self‐aggregation of phenalenyl rings and the introduction of bulky substituents into the appropriate positions led to the formation of a one‐dimensional chain assembly. Single‐crystal X‐ray structural analysis indicated that the bond length alternation of the cumulene chain increased with decreasing temperature, along with improved overlapping of the phenalenyl rings. Variable‐temperature Raman spectroscopy and magnetic susceptibility measurements revealed that a localized spin pair within the molecule decouples at low temperatures, and a continuum spin system involving intra‐ and intermolecular spin–spin interactions emerges in the one‐dimensional chain. [ABSTRACT FROM AUTHOR]

Exciton delocalization in organic semiconducting polymers, affected by structures at a molecular level, plays a crucial role in modulating relaxation pathways, such as charge generation and singlet fission, which can boost device efficiency. However, the structural diversity of polymers and broad signals from typical electronic spectroscopy have their limits when it comes to revealing the interplay between local structures and exciton delocalization. To tackle these problems, we apply femtosecond stimulated Raman spectroscopy in archetypical conjugated oligothiophenes with different chain lengths. We observed Raman frequency dispersions of symmetric bond stretching modes and mode‐specific kinetics in the S1 Raman spectra, which underpins the subtle and complex interplay between exciton delocalization and bond length alternation along the conjugation coordinate. Our results provide a more general picture of exciton delocalization in the context of molecular structures for conjugated materials. [ABSTRACT FROM AUTHOR]

Two distinct points on the potential energy curve (PEC) of a pairwise interaction, the zero‐energy crossing point and the point where the stretching force constant vanishes, allow us to anticipate the range of possible distances between two atoms in diatomic, molecular moieties and crystalline systems. We show that these bond‐stability boundaries are unambiguously defined and correlate with topological descriptors of electron‐density‐based scalar fields, and can be calculated using generic PECs. Chemical databases and quantum‐mechanical calculations are used to analyze a full set of diatomic bonds of atoms from the s‐p main block. Emphasis is placed on the effect of substituents in C−C covalent bonds, concluding that distances shorter than 1.14 Å or longer than 2.0 Å are unlikely to be achieved, in agreement with ultra‐high‐pressure data and transition‐state distances, respectively. Presumed exceptions are used to place our model in the correct framework and to formulate a conjecture for chained interactions, which offers an explanation for the multimodal histogram of O−H distances reported for hundreds of chemical systems. [ABSTRACT FROM AUTHOR]

A four‐coordinate cobalt–imido complex, (tBumPNP)Co=NMes (tBumPNP=modified PNP pincer ligand) has been synthesized from addition of 2,4,6‐trimethylphenylazide (Mes–N3) to the corresponding dinitrogen complex. The solid‐state structure determined by X‐ray diffraction established a rare, idealized planar geometry with a Co=N bond distance of 1.716(2) Å. Magnetic measurements revealed an S=1 ground state with CAS‐SCF calculations supporting radical character on the imide nitrogen. Thermolysis of the cobalt–imido compound induced selective insertion of the imido group into a Co−P bond and yielded a three‐coordinate cobalt complex with a distorted T‐shaped geometry. Transition state analysis conducted with DFT calculations established the thermodynamic stability of the P–N coupled product and provided insight into the exclusive selectivity. [ABSTRACT FROM AUTHOR]

It is here reported that the NaBH3− cluster exhibits a Na⋅B one‐electron bond, a well‐established type of electron‐deficient bonding in the literature. The topological analysis of the electron localization function, at the correlated level, reveals that Na−, when approaching the bonding distance, fairly distributes its valence electron pair between two lobes. One of these electrons is used to bond with BH3, which participates through its boron empty p‐orbital. Furthermore, the bonding situation of LiBH3−, KBH3−, MgBH3, and CaBH3 global minima structures are similar to that of NaBH3−, extending the family of these new one‐electron bond systems with biradicaloid character. [ABSTRACT FROM AUTHOR]

Removing or adding kernel atoms of metal nanoclusters (NCs) without leaving a trace is a substantial challenge because the kernel atoms are inside and covered by the outer staples. However, such kernel tuning is very important for improving the properties and acquiring an in‐depth understanding of the kernel‐property correlation. Photoluminescence (PL) is one of the most intriguing characteristics of metal NCs but has not been well understood until now. Inspired by these challenges/questions, we conducted this study and, for the first time, achieved the traceless removal of two kernel atoms in a gold nanocluster by applying a simple thermal treatment and revealed its impact on PL. Further, we demonstrated that the kernel Au‐Au bond length can be an indicator for a comparison of the PL or kernel charge state between nanoclusters with similar kernel structures and sizes. [ABSTRACT FROM AUTHOR]

The majority of the protein structures have been elucidated under equilibrium conditions. The aim herein is to provide a better understanding of the dynamic behavior inherent to proteins by fabricating a label‐free nanodevice comprising a single‐peptide junction to measure real‐time conductance, from which their structural dynamic behavior can be inferred. This device contains an azobenzene photoswitch for interconversion between a well‐defined cis, and disordered trans isomer. Real‐time conductance measurements revealed three distinct states for each isomer, with molecular dynamics simulations showing each state corresponds to a specific range of hydrogen bond lengths within the cis isomer, and specific dihedral angles in the trans isomer. These insights into the structural dynamic behavior of peptides may rationally extend to proteins. Also demonstrated is the capacity to modulate conductance which advances the design and development of bioinspired electronic nanodevices. [ABSTRACT FROM AUTHOR]

Since carbon–carbon (C−C) covalent bonds are rigid and robust, the bond length is, in general, nearly constant and depends only on the bond order and hybrid orbitals. We report herein direct visualization of the reversible expansion and contraction of a C(sp3)−C(sp3) single bond by light and heat. This flexibility of a C−C bond was demonstrated by X‐ray analysis and Raman spectroscopy of hexaphenylethane (HPE)‐type hydrocarbons with two spiro‐dibenzocycloheptatriene units, the intramolecular [2+2] photocyclization of which and thermal cleavage of the resulting cyclobutane ring both occur in a single‐crystalline phase. The force constant of the contracted C−C bond is 1.6 times greater than that of the expanded bond. Since formation of the cyclobutane ring and contraction of the C−C bond lower the HOMO level by approximately 1 eV, the oxidative properties of these HPEs with a flexible C−C bond can be deactivated/activated by light/heat. [ABSTRACT FROM AUTHOR]

Reaction of CsF with ClF3 leads to Cs[Cl3F10]. It contains a molecular, propeller‐shaped [Cl3F10]− anion with a central μ3‐F atom and three T‐shaped ClF3 molecules coordinated to it. This anion represents the first example of a heteropolyhalide anion of higher ClF3 content than [ClF4]− and is the first Cl‐containing interhalogen species with a μ‐bridging F atom. The chemical bonds to the central μ3‐F atom are highly ionic and quite weak as the bond lengths within the coordinating XF3 units (X = Cl, and also calculated for Br, I) are almost unchanged in comparison to free XF3 molecules. Cs[Cl3F10] crystallizes in a very rarely observed A[5]B[5] structure type, where cations and anions are each pseudohexagonally close packed, and reside, each with coordination number five, in the trigonal bipyramidal voids of the other. [ABSTRACT FROM AUTHOR]

Excimers and exciplexes are defined as assemblies of atoms or molecules A/A′ where interatomic/intermolecular bonding appears only in excited states such as [A2]* (for excimers) and [AA′]* (for exciplexes). Their formation has become widely known because of their role in gas‐phase laser technologies, but their significance in general chemistry terms has been given little attention. Recent investigations in gold chemistry have opened up a new field of excimer and exciplex chemistry that relies largely on the preorganization of gold(I) compounds (electronic configuration AuI(5d10)) through aurophilic contacts. In the corresponding excimers, a new type of Au⋅⋅⋅Au bonding arises, with bond energies and lengths approaching those of ground‐state Au−Au bonds between metal atoms in the Au0(5d106s1) and AuII(5d9) configurations. Excimer formation gives rise to a broad range of photophysical effects, for which some of the relaxation dynamics have recently been clarified. Excimers have also been shown to play an important role in photoredox binuclear gold catalysis. [ABSTRACT FROM AUTHOR]

Halogen bonding is often described as being driven predominantly by electrostatics, and thus adducts between anionic halogen bond (XB) donors (halogen‐based Lewis acids) and anions seem counterintuitive. Such "anti‐electrostatic" XBs have been predicted theoretically but for organic XB donors, there are currently no experimental examples except for a few cases of self‐association. Reported herein is the synthesis of two negatively charged organoiodine derivatives that form anti‐electrostatic XBs with anions. Even though the electrostatic potential is universally negative across the surface of both compounds, DFT calculations indicate kinetic stabilization of their halide complexes in the gas phase and particularly in solution. Experimentally, self‐association of the anionic XB donors was observed in solid‐state structures, resulting in dimers, trimers, and infinite chains. In addition, co‐crystals with halides were obtained, representing the first cases of halogen bonding between an organic anionic XB donor and a different anion. The bond lengths of all observed interactions are 14–21 % shorter than the sum of the van der Waals radii. [ABSTRACT FROM AUTHOR]

Milling two equivalents of K[1,3‐(SiMe3)2C3H3] (=K[A′]) with MgX2 (X=Cl, Br) produces the allyl complex [K2MgA′4] (1). Crystals grown from toluene are of the solvated species [((η6‐tol)K)2MgA′4] ([1⋅2(tol)]), a trimetallic monomer with both bridging and terminal (η1) allyl ligands. When recrystallized from hexanes, the unsolvated 1 forms a 2D coordination polymer, in which the Mg is surrounded by three allyl ligands. The C−C bond lengths differ by only 0.028 Å, indicating virtually complete electron delocalization. This is an unprecedented coordination mode for an allyl ligand bound to Mg. DFT calculations indicate that in isolation, an η3‐allyl configuration on Mg is energetically preferred over the η1‐ (σ‐bonded) arrangement, but the Mg must be in a low coordination environment for it to be experimentally realized. Methyl methacrylate is effectively polymerized by 1, with activities that are comparable to K[A′] and greater than the homometallic magnesium complex [{MgA′2}2]. [ABSTRACT FROM AUTHOR]

Elucidating structural roles in photoinduced charge transfer is indispensable, as nuclear rearrangements are simultaneously usually involved in the dynamics. However, it is hard to evaluate whether the structural changes occur or not by using conventional time‐resolved electronic spectroscopy. Here, time‐resolved impulsive stimulated Raman spectroscopy is applied to record the evolution of vibrational snapshots during charge‐separation dynamics of donor–acceptor–donor‐type quadrupolar perylene bisimide in real time. Drastic frequency shifts were observed for several Raman bands with their population kinetics, thus symmetry‐breaking charge separation accompanies significant structural changes, as supported by (TD)‐DFT calculations. A comparison between time‐resolved Raman spectra of the neutral S1 state and the radical anion species shows that the spectral signatures, especially in high‐frequency regions, provide important clues to bond length alternation patterns in the PBI core. [ABSTRACT FROM AUTHOR]

The efficient synthesis and electronic properties of two large‐size cove‐edged nanographenes (NGs), CN1 and CN2, are presented. X‐ray crystallographic analysis reveals a contorted backbone for both molecules owing to the steric repulsion at the inner cove position. Noticeably, the dominant structures of these molecules contain four (for CN1) or six (for CN2) localized C=C double bonds embedded in nine (for CN1) or twelve (for CN2) aromatic sextet rings according to Clar's formula, which is supported by bond length analysis and theoretical (NICS, ACID) calculations. Furthermore, Raman spectra exhibit a band associated with the longitudinal CC stretching mode of olefinic double bonds. Owing to the existence of the additional olefinic bonds, both compounds show a small band gap (1.84 eV for CN1 and 1.37 eV for CN2). They also display moderate fluorescence quantum yield (35 % for CN1 and 50 % for CN2) owing to the contorted geometry, which can suppress aggregation in solution. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons with hexagons/pentagons or hexagons/heptagons have been intensively investigated in recent years, but those with simultaneous presence of hexagons, pentagons and heptagons remain rare. In this paper, we report dicyclohepta[ijkl,uvwx]rubicene (DHR), a non‐benzenoid isomer of dibenzo[bc,kl]coronene with two pentagons and two heptagons. We developed an efficient and scalable synthetic method for DHR by using Scholl reaction and dehydrogenation. Crystal structure of DHR shows that the benzenoid rings, two pentagons and two heptagons are coplanar. The bond lengths analysis and the ICSS(1)zz and LOL‐π calculations indicate that the incorporation of two formal azulene moieties has an effect on the conjugated structure. The π‐electrons of benzenoid and pentagon rings are more delocalized. Cyclic voltammetry studies indicate that DHR shows multiple oxidation and reduction potentials. Interestingly, DHR exhibits unusual S0 to S2 absorption and abnormal anti‐Kasha S2 to S0 emission. Moreover, crystals of DHR exhibit semiconducting behaviour with hole mobility up to 0.082 cm2 V−1 s−1. [ABSTRACT FROM AUTHOR]

Cyanogen diluted in argon was reacted with laser ablated Zn atoms to produce the NCZnCN and NCZnZnCN cyanides and higher energy isocyanides ZnNC, CNZnNC, and CNZnZnNC, which were isolated in excess argon at 4 K. These reaction products, identified from the matrix infrared spectra of their ‐CN and ‐NC chromophore ligand stretching modes, were confirmed by 13C and 15N isotopic substitution and comparison with frequencies calculated by the B3LYP and CCSD(T) methods using the all electron aug‐cc‐pVTZ basis sets. The cyanide and isocyanide products were increased markedly by mercury arc UV photolysis, which covers the zinc atomic absorption. The above electronic structure calculations that produce appropriate ligand frequencies for these dizinc products also provide their Zn−Zn bond lengths: CCSD(T) calculations find a short 2.367 Å Zn−Zn bond in the NCZnZnCN cyanide, a shorter 2.347 Å Zn−Zn bond in the 37.4 kJ mol−1 higher energy isocyanide CNZnZnNC, and a longer 4.024 Å bond in the dizinc van der Waals dimer. Thus, the diatomic cyanide (‐CN) and isocyanide (‐NC) ligands are as capable of stabilizing the Zn−Zn bond as many much larger ligands based on their measured and our calculated Zn−Zn bond lengths. This is the first example of dizinc complexes stabilized by different ligand isomers. Additional weaker bands in this region can be assigned to the analogous trizinc molecules NCZnZnZnCN and CNZnZnZnNC. [ABSTRACT FROM AUTHOR]

An exceptionally strong solvation effect of dimethyl sulfoxide (DMSO) on I2 is identified by the largest shift observed so far of the I2 Raman peak with respect to I2 vapor and by elongated I−I bond lengths in first‐principles molecular‐dynamics simulations. This effect together with strong binding by an RuO2 surface to I2 is found to invert the direction of the reaction I−+I2⇌I3− to the left‐hand side. Inspired by this finding, we prepared a Li–O2 battery with the Li/DMSO+LiI/RuO2 structure. The synergic action of DMSO and RuO2 on I2 is found to suppress the shuttle effect of the redox mediator (RM) by anchoring I2 molecules, the oxidation product of the RM. Significantly enhanced stability is demonstrated over 100 cycles at charging voltage below 3.65 V. [ABSTRACT FROM AUTHOR]

A mononuclear nonheme manganese(IV)–oxo complex binding the Ce4+ ion, [(dpaq)MnIV(O)]+–Ce4+ (1‐Ce4+), was synthesized by reacting [(dpaq)MnIII(OH)]+ (2) with cerium ammonium nitrate (CAN). 1‐Ce4+ was characterized using various spectroscopic techniques, such as UV/Vis, EPR, CSI‐MS, resonance Raman, XANES, and EXAFS, showing an Mn−O bond distance of 1.69 Å with a resonance Raman band at 675 cm−1. Electron‐transfer and oxygen atom transfer reactivities of 1‐Ce4+ were found to be greater than those of MnIV(O) intermediates binding redox‐inactive metal ions (1‐Mn+). This study reports the first example of a redox‐active Ce4+ ion‐bound MnIV‐oxo complex and its spectroscopic characterization and chemical properties. [ABSTRACT FROM AUTHOR]