Chain-Like Pentanuclear Complexes: Syntheses, Crystal Structures and Long-Range Electronic Interactions of Cyanido-Bridged MRu (M=Fe, Ru).

In this work, we report the design and synthesis of two chain-like pentanuclear cyanido-bridged complexes trans-[Ru(bpy)(μ-CN)][cis-Ru(bpy)(μ-NC)M(dppe)Cp*][PF] (M=Fe, 1; M=Ru, 2) and the electronic communication properties of their oxidized products 1 (m=6, 7, 8) and 2 (n=5, 6, 7, 8). The single-crystal X-ray diffraction analysis of 1 (m=4, 6, 7) and 2 show that 1 and 2 possess a Z-type array structure, 1 is a U-type one, and 1 exhibits both the types. The investigations indicate that both 1 and 2 show an extraordinarily strong electronic interaction between the two side Ru across the central NC-Ru-CN, leading to the formation of a fully delocalized cyanidometal Ru-Ru-Ru bridge for both three-electron oxidized states 1 and 2.

Fluorescent Dye-Based Chiral Crystalline Organic Salt Networks for Circularly Polarized Luminescence.

A facile and general strategy is developed herein for the construction of circularly polarized luminescence (CPL) materials with simultaneously high fluorescence quantum efficiency (Φ) and large luminescence dissymmetry factor (g). The self-assembly of fluorescent dye, disodium 4,4'-bis(2-sulfonatostyryl)biphenyl (CBS), with chiral diamines such as (R,R)/(S,S)-1,2-diaminocyclohexane (R/S-DACH) and R/S-1,2-diaminopropane (R/S-DAP), produces four chiral crystalline organic salt networks (COSNs). These as-synthesized organic salts emit strong blue-color CPL upon excitation, with both high Φ and g values of up to 79% and 0.

Bifunctional Oxygen-Defect Bismuth Catalyst toward Concerted Production of HO with over 150% Cell Faradaic Efficiency in Continuously Flowing Paired-Electrosynthesis System.

The electrosynthesis of hydrogen peroxide (HO) from O or HO via the two-electron (2e) oxygen reduction (2e ORR) or water oxidation (2e WOR) reaction provides a green and sustainable alternative to the traditional anthraquinone process. Herein, a paired-electrosynthesis tactic is reported for concerted HO production at a high rate by coupling the 2e ORR and 2e WOR, in which the bifunctional oxygen-vacancy-enriched BiO nanorods (O-BiO-EO), obtained through electrochemically oxidative reconstruction of Bi-based metal-organic framework (Bi-MOF) nanorod precursor, are used as both efficient anodic and cathodic electrocatalysts, achieving concurrent HO production at both electrodes with high Faradaic efficiencies. Specifically, the coupled 2e ORR//2e WOR electrolysis system based on such distinctive oxygen-defect Bi catalyst displays excellent performance for the paired-electrosynthesis of HO, delivering a remarkable cell Faradaic efficiency of 154.

Self-supported bimetallic array superstructures for high-performance coupling electrosynthesis of formate and adipate.

The coupling electrosynthesis involving CO upgrade conversion is of great significance for the sustainable development of the environment and energy but is challenging. Herein, we exquisitely constructed the self-supported bimetallic array superstructures from the Cu(OH) array architecture precursor, which can enable high-performance coupling electrosynthesis of formate and adipate at the anode and the cathode, respectively. Concretely, the faradaic efficiencies (FEs) of CO-to-formate and cyclohexanone-to-adipate conversion simultaneously exceed 90% at both electrodes with excellent stabilities.

Central Metal-Triggered Structural Transformation of a 2D Layered MOF: Mechanistic Studies and Applications.

The structural transformation of metal-organic frameworks (MOFs) has attracted increasing interests, which has not only produced various new structures but also served as a fantastic platform for MOF-based kinetic analysis. Multiple reaction conditions have been documented to cause structural transformation; nevertheless, central metal-induced topological alteration of MOFs is rare. Herein, we reported a structural transformation of a 2D layered Cd-MOF driven by Cd(II) ions.

Rare-earth-based chalcogenides and their derivatives: an encouraging IR nonlinear optical material candidate.

With the continuous development of laser technology and the increasing demand for lasers of different frequencies in the infrared (IR) spectrum, research on infrared nonlinear optical (NLO) crystals has garnered growing attention. Currently, the three main commercially available types of borate materials each have their drawbacks, which limit their applications in various areas. Rare-earth (RE)-based chalcogenide compounds, characterized by the unique f-electron configuration, strong positive charges, and high coordination numbers of RE cations, often exhibit distinctive optical responses.

Hierarchically Ordered Pore Engineering of Metal-Organic Framework-Based Materials for Electrocatalysis.

Ordered pore engineering that embeds uniform pores with periodic alignment in electrocatalysts opens up a new avenue for achieving further performance promotion. Hierarchically ordered porous metal-organic frameworks (HOP-MOFs) possessing multilevel pores with ordered distribution are the promising precursors for the exploration of ordered porous electrocatalysts, while the scalable acquisition of HOP-MOFs with editable components and adjustable pore size regimes is critical. This review presents recent progress on hierarchically ordered pore engineering of MOF-based materials for enhanced electrocatalysis.

BaInMnSiOS: First Hexanary Oxychalcogenide Containing an Infrequent Three-Dimensional Noncentrosysmmetric Framework.

Noncentrosymmetric (NCS) oxychalcogenides have attracted great attention in recent years due to their immense potential as candidates for IR nonlinear-optical (NLO) applications. Despite notable advancements in this field, the discovery of oxychalcogenides with three-dimensional (3D) framework structures remains a formidable challenge. In this study, we report the discovery of the first hexanary oxychalcogenide, BaInMnSiOS, exhibiting second-order NLO activity, using a high-temperature solid-phase method.

Fine-tuning of thermally induced SCO behaviors of trinuclear cyanido-bridged complexes by regulating the electron donating ability of C-terminal fragments.

To achieve fine regulation of Fe SCO behavior, a series of trinuclear cyanido-bridged complexes (1-4) (1, M = Fe2 and = 1; 2, M = Fe2 and = 4; 3, M = Fe2 and = 5; 4, M = Ru and = 5; CpMe = alkyl cyclopentadienyl with = 1, 4, 5; dppe = 1,2-bis-(diphenylphosphino)ethane; abpt = 4-amino-3,5-bis-(pyridin-2-yl)-1,2,4-triazole and OTf = CFSO) were synthesized and fully characterized by using elemental analysis, X-ray crystallography, magnetic measurements, variable-temperature IR spectroscopy and Mössbauer spectroscopy. It is worth mentioning that different from many mononuclear Fe(abpt)X (X = NCS, NCSe, N(CN), C(CN), (NC)CC(OCH)C(CN), (NC)CC(OCH)C(CN), CSO and Cl) complexes with more than one polymorph, only one polycrystalline form was found in complexes 1-4. Moreover, the thermally induced SCO behaviors of these four complexes are independent of intermolecular π-π interactions.

Azo-Cyanamide Bridged Dinuclear Iron Complexes Exhibiting no Electronic Coupling but Moderate Magnetic Coupling between the two Iron Centers.

To investigate the effect of long-distance organic ligand on electronic coupling between metallic atoms, the mononuclear and dinuclear complexes [Cp(dppe)Fe(apc)] (1), [{Cp(dppe)Fe}(μ-adpc)] (2), [{CpMe(dppe)Fe}(μ-adpc) (3) and their oxidized complexes [Cp(dppe)Fe(apc)][PF] (1[PF]), [{Cp(dppe)Fe}(μ-adpc)][PF] (2[PF]), [{CpMe(dppe)Fe}(μ-adpc)][PF] (3[PF]) (Cp=1,3-cyclopentadiene, CpMe=1,2,3,4,5-pentamethylcyclopentadiene, dppe=1,2-bis(diphenylphosphino)ethane), apc=4-azo(phenylcyanamido)benzene and adpc=4,4'-azodi(phenylcyanamido)) were synthesized and characterized by cyclic voltammetry, UV-vis, single-crystal X-ray diffraction and Mössbauer spectra. Electrochemical measurements showed no electronic coupling between the two terminal Fe units, However, the investigation results of the magnetic properties of the two-electron oxidized complexes indicate the presence of moderate antiferromagnetic coupling across 18 Å distance.

Syntheses, crystal structures and MMCT properties of diruthenium-based cyanido-bridged RuV/VI2-NC-Ru complexes.

The goal of this study was to investigate how the electron-donating capability around the lower valent metal ion and the electron-accepting capability of the higher valent metal ion influence metal to metal charge transfer (MMCT) properties in mixed-valence complexes. A series of trinuclear ruthenium complexes represented as [Ru(ap-4-Me)(CHCOO)NCRuCpMe(dppe)][PF] (CpMe = polymethylcyclopentadienyl, = 0, 1, and 5; and dppe = 1, 2-bis(diphenylphosphino)ethane, ap-4-Me = 2-anilino-4-methylpyridine) and their one-electron oxidized products were synthesized and fully characterized. The UV-vis-NIR spectra confirmed that as the electron donor character of the CpMe(dppe)RuCN fragment enhanced or the electron-accepting capability of the higher valent diruthenium cluster increased, the Ru → RuV2 or RuVI2 Ru MMCT bands shifted to lower energies, which was supported by TDDFT calculations.

Different delocalized ranges in mixed valence cyanido-metal-bridged Fe-Ru-Fe complexes controlled by terminal ligand substitution modification.

In order to investigate the properties of metal to metal charge transfer (MMCT) influenced by the relative energy level between the bridging unit and the terminal unit, two groups of heterotrimetallic cyanido-metal-bridged complexes, -[Cp(dppe)Fe-CN-Ru(MeOpy)-NC-Fe(dppe)Cp][X] (1[X]n; = 2, 3, or 4; X = PF or BF) (Cp = cyclopentadiene, dppe = 1,2-bis(diphenylphosphino)ethane, MeOpy = 4-methoxypyridine) and [Cp*(dppe)Fe-CN-Ru(MeOpy)-NC-Fe(dppe)Cp*] [X] (2[X]n; Cp* = 1,2,3,4,5-pentamethylcyclopentadiene; = 2, 3, or 4; X = PF or BF) were synthesized and fully characterized. The crystallography data suggest different oxidation sites in the ground state for one-electron oxidation products 13+ and 23+, and the electrochemical and Mössbauer spectra suggest that in the one-electron oxidation compounds 13+, the charge is delocalized all along the trimetal backbone Fe-Ru-Fe, while in 23+, the charge is rather delocalized between the two metal parts Fe-Ru. Further oxidation of N3+ gives N4+ ( = 1 or 2), during which a spin transfer towards the terminal units is observed in both series.

A lithium-scandium sulfate with second-harmonic generation response and deep-ultraviolet transparency.

A new beryllium-free deep-UV transparent NLO crystal Li(HO)Sc(SO) features a two-dimensional [Sc(SO)] framework consisting of twisted [ScSO] units decorated by [LiO(HO)] groups into a unique layer. Remarkably, Li(HO)Sc(SO) exhibits a phase-matching SHG response of 0.7 × KDP and a deep-UV cutoff edge below 190 nm.

Metal-Metal Charge Transfer Properties of a Series of Trinuclear Fe Ru and Corresponding Pentanuclear Fe Ru Ag Cyanido-Bridged Complexes.

A series of trimetallic cyanidometal-bridged compounds [Me Cp(dppe)Fe -(μ-NC)-Ru (MeOpy) -(μ-CN)-Fe (dppe)CpMe ] - [PF ] (N[PF ] , n=0, N =1; n=1, N=2; n=3, N=3; Cp=cyclopentadiene, dppe=1,2-bis(diphenylphosphino)ethane, MeOpy=4-methoxypyridine) and their one- and two-electron oxidized compounds N and N were synthesized and characterized. Meanwhile, a series of corresponding linear cyanido-bridged pentanuclear compounds [Me Cp(dppe)Fe -(μ-NC)-Ru (MeOpy) -(μ-NC)-Ag -(μ-CN)-Ru (MeOpy) -(μ-CN)-Fe (dppe)CpMe ][BF ] (M[BF ] , n=0, M=4; n=1, M=5; n=3, M=6) were also obtained and well characterized. The investigations suggest that in the trinuclear system there exists remote interaction between the two Fe centers, but no significant interactions exist across the central silver unit between the metals on the two sides of the silver center in the pentanuclear system.

Electronic Transition and Magnetic Coupling Regulation in Trimetallic Complexes Featuring a New Bridging Ligand Obtained by Oxidative Addition.

A series of trimetallic complexes [Fe(μ-L)(py)]M() ( = 2, M = Mn, ; Fe, ; Co, ; Zn, ; = 3, M = Cd, ) with a new bridging ligand L (deprotonated 1,2--bis(2-mercaptoanil) oxalimidic acid) were synthesized and fully characterized by elemental analysis, single-crystal X-ray crystallography, IR, and Mössbauer spectra. Interestingly, the bridging ligand was obtained by oxidative addition of the (gma) ligand from the mononuclear precursor Fe()py (gma = glyoxal-bis(2-mercaptoanil)). In the obtained complexes, the bridging ligand L coordinates to the terminal Fe ions (intermediate-spin with S = 3/2) by the N, S atoms, and coordinate to the central metal M ion by the four O atoms.

Si Doping-Induced Electronic Structure Regulation of Single-Atom Fe Sites for Boosted CO Electroreduction at Low Overpotentials.

Transition metal-based single-atom catalysts (TM-SACs) are promising alternatives to Au- and Ag-based electrocatalysts for CO production through CO reduction reaction. However, developing TM-SACs with high activity and selectivity at low overpotentials is challenging. Herein, a novel Fe-based SAC with Si doping (Fe-N-C-Si) was prepared, which shows a record-high electrocatalytic performance toward the CO-to-CO conversion with exceptional current density (>350.

Coexistence of Three Different Spin States in a Cyanido-Bridged Trinuclear Iron(III) Complex with an Unusual Fe to Ligand Charge Transfer.

We report a trinuclear iron(III) cyanido-bridged complex trans-[CpMe Fe (dppe)(CN)] [Fe (L )][PF ] (2[PF ] ) as the oxidation product of binuclear complex [CpMe (dppe)Fe CN-Fe (L )][PF ] (1[PF ]) (CpMe =1, 2, 4-trimethyl-1,3-cyclo-pentadienyl, dppe=1,2-bis(diphenylphosphino)ethane, L =pentane-2,4-dione-bis(S-methylisothiosemicarbazonato). Complex 1[PF ] possesses an intermediate-spin five-coordinated Fe (S=3/2) which couples antiferromagnetically to the π-radical ligand (L⋅ ) and shows a LMCT (ligand to metal charge transfer) transition from (L⋅ ) to Fe and the Fe →Fe MMCT transition. Upon oxidation of 1[PF ], (L⋅ ) loses one electron to be the strong electron-attracting ligand (L ) and the intermediate-spin five-coordinated Fe (S=3/2) becomes a low-spin six-coordinated Fe (S=1/2) in 2[PF ] .

Directional editing of self-supported nanoarray electrode for adaptive paired-electrolysis.

Anodic oxidation assisted hydrogen production under mild conditions powered by renewable electricity represents a sustainable approach to energy conversion systems. Here, we fabricated a versatile and universal self-supported nanoarray platform that can be intelligently edited to achieve adaptive electrocatalysis for alcohol oxidation reactions and hydrogen evolution reaction (HER). The obtained self-supported nanoarray electrocatalysts exhibit excellent catalytic activity due to the integration of multiple merits of rich nanointerface-reconstruction and self-supported hierarchical structures.

Rational Design of a Rare-Earth Oxychalcogenide Nd [Ga O S ][Ge O ] with Superior Infrared Nonlinear Optical Performance.

Inorganic chalcogenides have been studied as the most promising infrared (IR) nonlinear optical (NLO) candidates for the past decades. However, it is proven difficult to discover high-performance materials that combine the often-incompatible properties of large energy gap (E ) and strong second harmonic generation (SHG) response (d ), especially for rare-earth chalcogenides. Herein, centrosymmetric Cs [Sb O ][Ge O ] is selected as a maternal structure and a new noncentrosymmetric rare-earth oxychalcogenide, namely, Nd [Ga O S ][Ge O ], is successfully designed and obtained by the module substitution strategy for the first time.

New lead-iodide formates with a strong second-harmonic generation response and suitable birefringence obtained by the substitution strategy.

Nonlinear optical (NLO) crystals featuring a strong second-harmonic generation (SHG) response and suitable birefringence to achieve phase-matching are in urgent demand in industrial and commercial applications. Based on the substitution strategy, two new NLO lead-iodide formates, K[PbI(HCOO)] and Rb[PbI(HCOO)], have been successfully synthesized using a moderate mixed-solvothermal method. K[PbI(HCOO)] and Rb[PbI(HCOO)] exhibit strong phase-matching SHG responses of 8 and 6.

Influence of the electronic effect of an ancillary ligand on MMCT and LMCT in localized cyanide-bridged complexes containing non-innocent ligands.

Mixed-valence (MV) complexes containing non-innocent ligands are excellent models for the investigation of the electron-transfer process. A series of twelve bimetallic cyanide-bridged complexes [CpMen(dppe)RuCNFeLx][A] (A = PF or I, CpMe = alkyl cyclopentadienyl, dppe = 1,2-bis (diphenylphosphino)ethane, and L = pentane-2,4-dione-bis (S-alkylisothiosemi-carbazonato); = 0, x = Methyl (Me), Ethyl (Et), -Propyl (Pr) and -Butyl (Bu), and A = PF, 1Me[PF6], 1Et[PF6], 1Pr[PF6], and 1Bu[PF6]; = 1, x = Me, Et, Pr, and Bu, and A = PF, 2Me[PF6], 2Et[PF6], 2Pr[PF6], and 2Bu[PF6]; = 5, x = Me, Et, Pr, and Bu, and A = I, 3Me[I], 3Et[I], 3Pr[I], and 3Bu[I]) have been synthesized and well characterized. The investigations demonstrate that all the cations of the complexes could be described with the basic electronic configuration , in which the fragment could be regarded as being delocalized.