Mononuclear and dinuclear copper-iodide complexes (1 and 2) based on a new benzimidazole-phosphine (N P) ligand have been synthesized. Both complexes exhibit yellowish-green phosphorescence at ambient temperature. Notably, the dinuclear complex 2 achieves high photoluminescence quantum yield (PLQY) of 49 %, which is considerably higher than that (6 %) observed for the mononuclear counterpart 1. The theoretical and experimental investigations suggest that the Cu2I2 core in 2 could increase in structural rigidity as well as promote the intersystem crossing (ISC) process, leading to high PLQY values as well as short radiative decay time of 4.42 mu s. This work is expected to inspire further research on developing copper-iodide complexes for efficient luminescence.

Hydrazine oxidation-assisted hydrogen evolution represents a promising avenue for energy-saving hydrogen production. However, the development of bifunctional catalysts with high atom economy and durability for both hydrazine oxidation reaction (HzOR) and hydrogen evolution reaction (HER) remains challenging. Here, a design is reported that combines sulfur-stabilized Pt clusters and Ni-N4 sites on nitrogen-doped carbon support (Ptn-S/Ni1-NC) for boosting alkaline hydrazine oxidation-assisted hydrogen evolution. Experimental and theoretical results reveal that the pre-coordinated sulfur atoms on Pt clusters provide strong metal-support interaction (SMSI) for the homogeneous distribution of Pt clusters, allowing Pt clusters to remain ultrafine, which ensures high atom utilization and sufficient active sites. Moreover, the electronic interactions and synergistic adsorption mechanism of Pt clusters and adjacent Ni-N4 sites markedly accelerate the H2O dissociation and HzOR kinetics. As a result, the Ptn-S/Ni1-NC catalysts exhibit exceptional catalytic activity, achieving an ultrasmall HER overpotential of 19 mV and an ultralow HzOR working potential of -21 mV at 10 mA cm-2 current density. In addition, the overall hydrazine oxidation-assisted splitting (OHzS) electrolyzer can reach 10 mA cm-2 with a low cell voltage of 79 mV and good long-term stability in 1.0 m KOH/0.5 m N2H4.

The selective synthesis of valuable azo- and azoxyaromatic chemicals via transfer coupling of nitroaromatic compounds has been achieved by fine-tuning the catalyst structure. Here, a direct method to modulate nitrobenzene reduction and selectively alter the product from azobenzene to azoxybenzene by employing the size effect of Au is reported. Au nanoclusters (NCs) with smaller sizes embedded in ZIF-8 controllably converted nitrobenzene into azoxybenzene, while supported Au nanoparticles (NPs) selectively catalyzed nitrobenzene reduction to azobenzene. X-ray photoelectron spectroscopy (XPS) and Diffuse reflectance infrared Fourier transform spectroscopy on CO adsorption (CO-DRIFTS) of Au NC/ZIF-8 revealed a higher valence state and a lower electron density of Au than that of Au NP/ZIF-8, combined with the desorption of azoxybenzene from the Au NC and Au NP surface, suggesting that the Au NCs with lower electron density exhibit stronger adsorption. Density functional theory (DFT) calculations and charge density difference maps indicated that azoxybenzene bonded to Au NC/ZIF-8 with greater adsorption energy, resulting in more electron transfer between azoxybenzene and the generated Au sites, which inhibited further reduction of azoxybenzene and resulted in high azoxybenzene selectivity. The application of the size effect of Au particles to regulate nitrobenzene transfer coupling provided new insights into the structure-selectivity relationships.

The fabrication of hybrid active sites that synergistically contain nanoclusters and single atoms (SAs) is vital for electrocatalysts to achieve excellent activity and durability. Herein, we develop a ligand-assisted pyrolysis strategy using nanoclusters (Au4Pd2(SC2H4Ph)8) with alloy cores and protected ligands to build AuPd cluster sites embraced by satellite Pd SAs. In the thermal drive control process, different thermodynamic properties of the alloy atoms and the confinement effects of organic ligands allow for the mild spillover of the single-component metal Pd, resulting in the formation of AuPd alloy nanoclusters tightly encompassed by isolated Pd atoms. Experiments and theoretical calculations indicated that the satellite Pd atoms can optimize the electronic structure of the AuPd nanoclusters and Au sites in the alloy to facilitate the adsorption and dissociation of H2O, thus enhancing the hydrogen evolution reaction (HER) activity. The optimal AuPdNCs/PdSAs-600 exhibits outstanding electrocatalytic activity toward HER, with overpotentials of 21 and 38 mV at 10 mA cm-2 in acidic and alkaline media, respectively. Moreover, the mass activity and turnover frequency of AuPdNCs/PdSAs-600 are one order of magnitude higher than those of commercial Pd/C and Pt/C catalysts. This facile strategy for constructing hybrid catalytic centers using ligand-protected nanoclusters provides efficient insights for the further design of nanocluster-based electrocatalysts synergized by SAs.

Endowing thermally activated delayed fluorescence (TADF) emitters simultaneously with high emission quantum yields and short radiative lifetimes is of fundamental significance in optoelectronic field. In this contribution, two neutral tetrahedral Cu(I) complexes (1 and 2) have been developed, which realize blue-TADF with photo-luminescent quantum yield of up to 85 % due to the high structural rigidity. Meanwhile, short TADF lifetimes (<10 mu s) of the Cu(I) complexes suggest that the synergistic effects of small Delta E(S1-T1) gap and relatively large SOC value introduced by the copper ion could facilitate fast reverse ISC processes compared to the typical organic-TADF materials.

Novel luminescent dinuclear and mononuclear cycloplatinated(II) complexes (1-3 and 4-6) with OPPh3- and PPh3-functionalized 2-phenyl-triazole ligands (L1-L3 and L4-L6) are synthesized and structural characterized. The coordination of the individual Pt(II) centers in dinuclear and mononuclear complexes are [Pt(N–N)(C^N)] and [Pt(P^N)(C^N)], where N–N, C^N and P^N mean a bridging coordination, a five-membered ring and a six-membered ring, respectively. Bulky 2-phenyltriazole ligands L1-L6 can reduce intermolecular π–π and Pt–Pt interactions and increase rigidity of complexes, therefore these complexes show superior monomeric emissions with the quantum yields of 14.5%-25.7% in dichloromethane at 298K. The luminescence mainly originates from mixed 3LC/3MLCT states.

The development of facile tailoring approach to adjust the intrinsic activity and stability of atomically-precise metal nanoclusters catalysts is of great interest but remians challenging. Herein, the well-defined Au 8 nanoclusters modified by single-atom sites are rationally synthesized via a co-eletropolymerization strategy, in which uniformly dispersed metal nanocluster and single-atom co-entrenched on the poly-carbazole matrix. Systematic characterization and theoretical modeling reveal that functionalizing single-atoms enable altering the electronic structures of Au 8 clusters, which amplifies their electrocatalytic reduction of CO 2 to CO activity by ~18.07 fold compared to isolated Au 8 metal clusters. The rearrangements of the electronic structure not only strengthen the adsorption of the key intermediates *COOH, but also establish a favorable reaction pathway for the CO 2 reduction reaction. Moreover, this strategy fixing nanoclusters and single-atoms on cross-linked polymer networks efficiently deduce the performance deactivation caused by agglomeration during the catalytic process. This work contribute to explore the intrinsic activity and stability improvement of metal clusters.

Two ionic mononuclear silver(I) complexes ( 1 and 2 ) with formula of [Ag(N<^>P)(Xantphos)]SbF 6 , where N<^>P = 2 - (benzo[ d ]thiazol) -2 -yl) diphenylphosphine derivatives, Xantphos = 4,5-Bis(diphenylphosphino)-9,9-dimethylxanthene, have been synthesized and characterized. Single crystal analysis reveals that the geometries around Ag(I) centers adopt distorted tetrahedron ( 1 ) and trigonal planar ( 2 ). In powder at 298 K, these complexes exhibit bright emissions with high photo -luminescent quantum yields of 55.2 % ( 1 ) and 46.7 % ( 2 ) and lifetimes of 0.426 ms ( 1 ) and 1.87 ms ( 2 ), respectively. The results suggested that these complexes containing bulky benzothiazole phosphine can realize efficient long-lived phosphorescence.

Four neutral mononuclear copper(I) complexes (1-4) with formula of [(N boolean AND P)Cu(PPh3)(2)] (1-2) and [(N boolean AND P)Cu (Xantphos)] (3-4) based on NH-deprotonated (2-(1H-benzimidazole)phenyl) diphenylphosphine ligands (N boolean AND P) and phosphine ancillary ligands have been synthesized. The copper(I) complexes exhibit bright thermally acti-vated delayed fluorescence at room temperature with photoluminescence quantum yield up to 43.5%. Upon grinding, the complexes display apparent bathochromic shift in the emission maxima of up to 50 nm (1). Meanwhile, the complexes display similar luminescence profiles to those of the origin samples exposed to CH3OH vapor. Single crystal X-ray and PXRD diffraction results demonstrate that the reversible mechanochromic luminescent (MCL) properties are ascribed to the transformation of crystalline and amorphous state dependent on the disruption and restoration of hydrogen bonds during external stimuli, which have been rarely observed in the copper(I)-based MCL materials hitherto. These findings clearly suggest that the introduction of switchable secondary interactions in mononuclear copper(I) complex is a large-scale synthesis strategy for multifunctional luminescent materials.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Precise control of the coordination structure of metal centers is an ideal approach to achieve reasonable selectivity, activity, and stability in the electrochemical reduction of CO2. In this work, the KOH activation strategy for preparation of hierarchically porous material containing Ni single‐atoms with axial‐oxygen coordination is reported. Spectroscopic measurements reveal the multiple roles of KOH as oxygen source, pore‐making reagent and promoter for the formation of key phthalocyanine structure. It exhibits superior surface area (1801 m2 g−1) and electrocatalytic performance (Faradaic efficiency of 94%, Turnover frequency of 11 362 h−1). Notably, KOH‐enabled architecture with abundant pores benefits the anchoring of Ni atoms and mass transfer for high activity and selectivity. Density functional theory calculations suggest that the axial‐oxygen ligand can promote the electronic delocalization of the Ni site for facilitating the *COOH formation and *CO desorption to efficiently produce CO.

Eight neutral luminescent cyclometalated platinum(II) complexes with general formula (piq)Pt(N boolean AND O) and (piq)Pt(N<^>P), where piq = 1-phenylisoquinoline, N boolean AND O = deprotonated (2-(1H-benzimidazole)-phenyl)diphenylphosphine oxide derivatives and N boolean AND P = deprotonated (2-(1H-benzimidazole)-phenyl)diphenylphosphine derivatives, have been synthesized and characterized. These complexes display distorted square-planar molecular geometries around platinum(II) centers without obvious pi-pi interactions and Pt-Pt metallophilic interactions in the crystal lattice, due to the presence of sterically bulky N boolean AND O and N boolean AND P benzimidazole ancillary ligands. Hence, these complexes exhibit good monomeric emissions with the luminescent quantum yields of 15%-23%, which are far more than that of (piq)Pt(acac) (0.9%) in dichloromethane (DCM) at 298 K. The emission colors of platinum(II) complexes can be finely tuned in the range 600-645 nm by changing the chelating types of ancillary ligands. The structured emission combined with microsecond emission lifetimes and the support of TD-DFT calculations for these complexes indicate that their emissions mainly come from an admixture of intraligand (3ILCT) and metal-to-ligand charge transfer (3 MLCT). (C) 2021 Elsevier B.V. All rights reserved.

Carbazole derived phosphine ligands containing pyridine moiety were designed and prepared. It allows the challenging Pd-catalyzed Markovnikov-selective alkoxycarbonylation of aliphatic alkenes to give the branched ester products (28 examples; 51–97% branch selectivity). Preliminary mechanistic studies support that the bridging bromide between Pd and Mn centers is crucial for the enhancement of regioselectivity.

Nitrile compounds are a class of high-value chemicals and versatile intermediates which can easily be transformed into a variety of useful products bearing functional groups such as carboxyl, carbamoyl, aminomethyl, ketyl and heterocyclic derivatives. Various thermal catalytic cyanation procedures have been devised and scaled up industrially while developing alternative methods are actively pursued. The access to these classes of molecules electrochemically offers greener alternatives to their preparation. The development of electrochemical synthesis of cyano-containing compounds under mild conditions with low energy consumption will imminently become indispensable approaches for industrial production of nitriles. The electrochemical cyanation presents many challenges from the toxicity of cyanide to the development of catalysts and the design of electrochemical cells. Electrochemical cyanation reaction offers promise to conveniently accessing nitriles but still requires efficient electro-catalysts, safe protocols and scale up considerations. This review discusses recent progress in the field of electrochemical synthesis of nitrile compounds placing emphasis on electro-synthetic and electro-catalytic mechanism aspects while making reference to original works to highlight the progress in this area.

Cyanation of benzylic C-N bonds is useful in the preparation of important α-aryl nitriles. The first general catalytic cyanation of α-(hetero)aryl amines, analogous to the Sandmeyer reaction of anilines, was developed using reductive cyanation with CO2/NH3. A broad array of α-aryl nitriles was obtained in high yields and regioselectivity by C-N cleavage of intermediates as ammonium salts. Good tolerance of functional groups such as ethers, CF3, F, Cl, esters, indoles, and benzothiophenes was achieved. Using 13CO2, a 13C-labeled tryptamine homologue (five steps, 31% yield) and Cysmethynil (six steps, 37% yield) were synthesized. Both electronic and steric effects of ligands influence the reactivity of alkyl nickel species with electrophilic silyl isocyanates and thus determine the reactivity and selectivity of the cyanation reaction. This work contributes to the understanding of the controllable activation of CO2/NH3 and provides the promising potential of the amine cyanation reaction in the synthesis of bio-relevant molecules.

Dinuclear and mononuclear cycloplatinated(II) complexes (1-3 and 4-6) with formulas [Pt(bt)(mu-L)](2) and Pt(bt)(L) [bt = 2-phenylbenzothiazole, mu-L = deprotonated diphenyl(2-(5-phenyl-4H-1,2,4-triazol-3-yl)phenyl)phosphine oxide derivatives for L1-L3, and L = deprotonated 3-(2-(diphenylphosphino)phenyl)-5-phenyl-4H-1,2,4-triazole derivatives for L4-L6] have been successfully synthesized and systematically characterized. Single-crystal X-ray analysis demonstrates that these complexes exhibit distorted square-planar geometries around Pt(II) centers. There are no apparent intermolecular pi-pi and Pt-Pt interactions owing to the presence of bulky ligands. Therefore, these complexes achieve excellent monomeric emission in solution, PMMA films, and the solid state with a photoluminescence quantum yield (Phi) up to 67.3% in the solid state. The photophysical behaviors associated with theoretical investigations reveal that the emissions of these complexes possess primarily a (LC)-L-3 feature together with some (MLCT)-M-3 character.

Triangular three-coordinated copper(I) halide complexes (1 (I), 2 (Br)) were developed based on a rigid bidentate P-donor ligand functionalized with electron-deficient pyridoimidazole moiety. The results of the temperature-dependent spectroscopic properties reveal that both Cu(I) complexes in crystalline powder at 298 K achieve orange thermally activated delayed fluorescence (TADF) with high photoluminescence quantum yields of 77% for 1 and 56% for 2, and microsecond lifetimes of 55.1 mu s (1) and 73.5 mu s (2), respectively. Additionally, aromatic C-H center dot center dot center dot pi interactions in molecular packing structures constitute an appealing class of crystallization-induced emission enhancement (CIEE) complexes. The results suggest that such highly efficient copper-based stimuli-responsive materials are beneficial for a broad range of applications.

Four mono- and two dinuclear Cu(I) complexes were synthesized based on novel 4-diphenylphosphino-benzimidazole ((PN)-N-boolean AND) derivatives, and their structures as well as photophysical properties were systematically investigated. X-ray crystallographic analysis reveals that the Cu(I) centers adopt pseudo-tetrahedral geometries. All the complexes in powder at 293 K display bright phosphorescence with the highest photoluminescent quantum yield of 37.6 %. The emission maxima could be finely tuned from 514 to 592 nm by the methoxy substituent on the (NP)-P-boolean AND ligands. The combined experimental results at different temperature (293 K and 77 K) and theoretical studies suggest that the nature of the emissive states can be mainly assigned as a dominant charge-transfer character involving major components of (3)(M+X) LCT transitions.