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Realizing high photoluminescence quantum yield (PLQY) in the near-infrared (NIR) region is challenging and valuable for luminescent material, especially for thermally activated delay fluorescence (TADF) material. In this work, we report two achiral cyclic trinuclear Au(I) complexes, Au3(4-Clpyrazolate)3 and Au3(4-Brpyrazolate)3 (denoted as Cl−Au and Br−Au) , obtained through the reaction of 4-chloro-1H-pyrazole and 4-bromo-1H-pyrazole with Au(I) salts, respectively. Both Cl−Au and Br−Au exhibit TADF with high PLQY (>70 %) in the NIR I (700–900 nm) (λmax = 720 nm) region, exceeding other NIR−TADF emitters in the solid state. Photophysical experiments and theoretical calculations confirmed the efficient NIR−TADF properties of Cl−Au and Br−Au were attributed to the small energy gap ΔE(S1-T2) (S = singlet, T = triplet) and the large spin-orbital coupling induced by ligand-to-metal-metal charge transfer of molecular aggregations. In addition, both complexes crystallize in the achiral Pna21 space group (mm2 point group) and are circularly polarized light (CPL) active with maxima luminescent dissymmetry factor |glum| of 3.4 × 10−3 ( Cl−Au ) and 2.7 × 10−3 ( Br−Au ) for their crystalline powder samples, respectively. By using Cl−Au as the emitting ink, 3D-printed luminescent logos are fabricated, which own anti-counterfeiting functions due to its CPL behavior dependent on the crystallinity.  相似文献   

4.
Treatment of the (isocyanide)gold(I) species LAuCl (L=tBuNC, 2,6‐Me2C6H3NC) with 4‐mercaptobenzoic acid in the presence of NaOMe yields the complexes [Au(4‐SC6H4CO2H)L] in good yield. Reaction of LAuCl with 2‐HSQn (Qn=quinoline) and 2‐HSPy (Py=pyridine) under the same conditions provides the thiolato compounds [Au(2‐SQn)L] and [Au(2‐SPy)L], respectively. A structural investigation of the pyridylthiolato compound revealed chains of molecules with alternating medium and long Au−Au interactions. Treatment of this compound with HBF4 results in the cationic species [Au(2‐HSPy)(2,6‐Me2C6H3NC)]+ as the BF4 salt. The same product is obtained on reaction of [AuCl(2,6‐Me2C6H3NC)] with AgOTf followed by HSPy. Treatment of the gold(I) halide compounds LAuCl (L=tBuNC, 2,6‐Me2C6H3NC) with potassium 1,3,4‐thiadiazole‐2,5‐dithiolate (KSSSK) leads to the isolation of dinuclear thiolatogold complexes [(AuL)2(SSS)]. These products go on to form insoluble polymers through loss of isocyanide on standing in solution. A single crystal of [{Au(tBuNC)}2(SSS)] was obtained and the subsequent structural analysis revealed one of the most complicated networks known based solely on aurophilic interactions. A good comparison to the ‘soft' S‐donation of the thiolato ligands was provided by the synthesis of a number of nitratogold(I)complexes with the anion bound through the ‘hard' O‐donor. Reaction of iPrNC and CyNC with Au(tht)Cl provided the complexes [AuCl(iPrNC)] and [AuCl(CyNC)], respectively. These compounds were found to yield the respective nitrato species [Au(NO3)iPrNC)] and [(Au(NO3)(CyNC)] on treatment with AgNO3. The nitrato complexes yielded single crystals enabling a structural investigation to be carried out. While [Au(NO3)(CyNC)] has a more conventional structure with dimers aligned into strings with alternating short and long aurophilic bonding, [Au(NO3)(iPrNC)] has a unique structure based on strings of alternating, corner‐sharing Au6 and Au8 units with short Au−Au contacts in edge‐sharing Au3 triangles.  相似文献   

5.
Hydrazine (N2H4) is considered as one of the most potential energy storage materials in liquid fuel cells, as it contains high energy and power density, and the high-efficiency oxidation of N2H4 in fuel cells has drawn great attention. However, the most used catalysts are expensive noble metal catalysts, thus the development of highly efficient non-noble metal catalysts is crucial to reduce the cost of hydrazine oxidation in practical industry. Herein, we synthesized a series of CoFe-layered double hydroxides (CoFe-LDHs) intercalated with different anions via a simple one-step co-precipitation method for the electrooxidation of hydrazine. Through altering the intercalated anions of CoFe-LDHs, the defects and the electronic structure can be well controlled, and the catalytic performance for the electrooxidation of hydrazine were well promoted by using NO3 intercalated into CoFe-LDH compared with other anions (like Cl, BO33−, CO32−). This work developed a series of hydrazine electrooxidation catalysts and established the relationship between the intercalated anions, the fine structure of the catalyst and the electrocatalytic performance.  相似文献   

6.
In bis(2‐carboxypyridinium) hexafluorosilicate, 2C6H6NO2+·SiF62−, (I), and bis(2‐carboxyquinolinium) hexafluorosilicate dihydrate, 2C10H8NO2+·SiF62−·2H2O, (II), the Si atoms of the anions reside on crystallographic centres of inversion. Primary inter‐ion interactions in (I) occur via strong N—H...F and O—H...F hydrogen bonds, generating corrugated layers incorporating [SiF6]2− anions as four‐connected net nodes and organic cations as simple links in between. In (II), a set of strong N—H...F, O—H...O and O—H...F hydrogen bonds, involving water molecules, gives a three‐dimensional heterocoordinated rutile‐like framework that integrates [SiF6]2− anions as six‐connected and water molecules as three‐connected nodes. The carboxyl groups of the cation are hydrogen bonded to the water molecule [O...O = 2.5533 (13) Å], while the N—H group supports direct bonding to the anion [N...F = 2.7061 (12) Å].  相似文献   

7.
The influence of orientation on the electrocatalytic hydrogenation of hydroquinone (HQ) chemisorbed at smooth polycrystalline platinum electrodes in aqueous solutions has been investigated; experimental measurements, performed in the absence of bulk (unadsorbed) HQ, were based upon thin-layer electrochemical techniques. The extent of hydrogenation was characterized by (i) nH. the average number of hydrogen atoms reacted per chemisorbed HQ molecule, and (ii) the electrolytic charge Qox for oxidation of chemisorbed organic which remained on the surface after the hydrogenation reaction. The measured values of nH indicate that the extent of HQ hydrogenation is (i) dependent upon the potential EHyd at which hydrogenation was earned out, and (ii) a sensitive function of its initial adsorbed orientation; at a given EHyd, nHis larger in the flat (η6) than in the edge (2,3-η2) orientation. Correlation of Qox with nH, indicates that an appreciable fraction of partially hydrogenated species is desorbed from the surface; this fraction, which is a function of EHyd, is larger in the 2.3-η2 than in the η6 orientation.  相似文献   

8.
The potential for coordination and H-transfer from Cp2MH2 (M=Zr, W) to gold(I) and gold(III) complexes was explored in a combined experimental and computational study. [(L)Au]+ cations react with Cp2WH2 giving [(L)Au(κ2-H2WCp2)]+ (L=IPr ( 1 ), cyclic (alkyl)(amino)carbene ( 2 ), PPh3 ( 3 ) and Dalphos-Me ( 4 ) [IPr=1,3-bis(diisopropylphenyl)imidazolylidene; Dalphos-Me=di(1-adamantyl)-2-(dimethylamino)phenyl-phosphine], while [Au(DMAP)2]+ (DMAP=p-dimethylaminopyridine) affords the C2-symmetric [Au(κ-H2WCp2)2]+ ( 5 ). The Dalphos complex 4 can be protonated to give the bicationic adduct 4 H, showing AuI⋅⋅⋅H+−N hydrogen bonding. The gold(III) Lewis acid [(C^N−CH)Au(C6F5)(OEt2)]+ binds Cp2WH2 to give an Au-H-W σ-complex. By contrast, the pincer species [(C^N^C)Au]+ adds Cp2WH2 by a purely dative W→Au bond, without Au⋅⋅⋅H interaction. The biphenylyl-based chelate [(C^C)Au]+ forms [(C^C)Au(μ-H)2WCp2]+, with two 2-electron-3-centre W−H⋅⋅⋅Au interactions and practically no Au−W donor acceptor contribution. In all these complexes, strong but polarized W−H bonds are maintained, without H-transfer to gold. On the other hand, the reactions of Cp2ZrH2 with gold complexes led in all cases to rapid H-transfer and formation of gold hydrides. Relativistic DFT calculations were used to rationalize the striking reactivity and bonding differences in these heterobimetallic hydride complexes along with an analysis of their characteristic NMR parameters and UV/Vis absorption properties.  相似文献   

9.
Ascorbate (H2A) is a well-known antioxidant to protect cellular components from free radical damage and has also emerged as a pro-oxidant in cancer therapies. However, such “contradictory” mechanisms underlying H2A oxidation are not well understood. Herein, we report Fe leaching during catalytic H2A oxidation using an Fe−N−C nanozyme as a ferritin mimic and its influence on the selectivity of the oxygen reduction reaction (ORR). Owing to the heterogeneity, the Fe-Nx sites in Fe−N−C primarily catalyzed H2A oxidation and 4 e ORR via an iron-oxo intermediate. Nonetheless, trace O2 produced by marginal N−C sites through 2 e ORR accumulated and attacked Fe-Nx sites, leading to the linear leakage of unstable Fe ions up to 420 ppb when the H2A concentration increased to 2 mM. As a result, a substantial fraction (ca. 40 %) of the N−C sites on Fe−N−C were activated, and a new 2+2 e ORR path was finally enabled, along with Fenton-type H2A oxidation. Consequently, after Fe ions diffused into the bulk solution, the ORR at the N−C sites stopped at H2O2 production, which was the origin of the pro-oxidant effect of H2A.  相似文献   

10.
The oxidation of catechol by molecular oxygen in the presence of a catalytic amount of copper(II) complex with 2-methyl-3-amino-(3H)quinazoline-4-one (MAQ) and various anions (Cl, Br, ClO 4 , SCN, NO 3 and SO 4 ) was studied. The catecholase biomimetic catalytic activity of the copper(II) complexes has been determined spectrophotometrically by monitoring the oxidative transformation of catechol to the corresponding light absorbing o-quinone (Q). The rate of the catalytic oxidation reaction was investigated and correlated with the catalyst structure, time, concentration of catalyst and substrate and finally solvent effects. Addition of pyridine or Et3N showed a dramatic effect on the rate of oxidation reaction. Kinetic investigations demonstrate that the rate of oxidation reaction has a first order dependence with respect to the catalyst and catechol concentration and obeying Michaelis–Menten Kinetics. It was shown that the catalytic activity depends on the coordination environment of the catalyst created by the nature of counter anions bound to copper(II) ion in the complex molecule and follows the order: Cl > NO 3 > Br > SO 4 > SCN > ClO 4 . To further elucidate the catalytic activity of the complexes, their electrochemical properties were investigated and the catecholase mimetic activity has been correlated with the redox potential of the Cu2+/Cu+ couple in the complexes.  相似文献   

11.
An investigation of the d-effect in the absence of ionic specific adsorption shows that the overall charge of the reactants in dimethylglyoxime (DMG) electroreduction on mercury from aqueous solutions of pH?2 equals+1, in agreement with a protonation reaction either preceding (DMG + H+DMGH++e → products) or else simultaneous with (DMG + H+ + e → products) the charge transfer. In the presence of the specifically adsorbed supporting anions I? and SCN? the logarithm Φ of the rate constant for DMG electroreduction corrected for diffuse-layer effects decreases linearly with an increase in the absolute value |qi| of the charge density at the inner Helmholtz plane due to the adsorbed anions. This behaviour is explained semiquantitatively by assuming that protonation takes place simultaneously with charge transfer, with the DMG molecule in the adsorbed state and the H3O+ ion in the non-adsorbed state. In this way the H3O+ ion, due to the screening effect of the surrounding diffuse-layer ions, escapes the accelerating attractive effect exerted by the adsorbed I? or SCN? ions; on the other hand these latter anions exert a retarding repulsive effect upon the electron transfer from the metal to the adsorbed DMG molecule.  相似文献   

12.
The reaction of 1,2- and 1,3-benzenedithiol C6H4(SH)2 with chloro(phosphine)gold(I) complexes R3PAuCl (R = Et, Ph) in the presence of triethylamine in tetrahydrofuran gives stable gold(I) complexes 1,2-C6H4(SAuPR3)2 [R = Et ( 1 ) and Ph ( 2 )] or 1,3-C6H4(SAuPPh3)2 ( 3 ), respectively, in high yield. The compounds have been characterized by analytical and NMR spectroscopic data. From the reaction of 1,2-C6H(SH)2 with Et3P? AuCl a by-product [(Et3P)2Au]+ [Au(1,2? C6H4S2)2]? ( 4 ) has also been isolated in low yield. The crystal structures of compounds 2 and 4 have been determined by single crystal X-ray diffraction. The gold(I) atoms in complex 2 are two-coordinate with bond angles S? Au? P of 175.2(1) and 159.5(1)°, Au? S bond distances of 2.304(1) and 2.321(1) å, and a short Au…?Au contact of 3.145(1) Å. The gold(I) atom in the cation of complex 4 is also linearly two-coordinate with a P? Au? P angle of 170.1(1) Å and Au? P distances of 2.296(3) and 2.298(3) Å. The geometry of the anion in 4 shows a square-planar coordination of gold(III) by two chelating 1,2-benzenedithiolate ligands with Au? S distances between 2.299(3) and 2.312(3) Å (for two crystallographically independent, centrosymmetrical anions in the unit cell).  相似文献   

13.
Four polypyridyl bridging ligands BL1−4 containing open‐chain crown ether, where BL1−3 formed by the condensation of 4,5‐diazafluoren‐9‐oxime with diethylene glycol di‐p‐tosylate, triethylene glycol di‐p‐tosylate, and tetraethylene glycol di‐p‐tosylate, respectively. BL4 formed by the reaction of 4‐(1,10‐phenanthrolin‐5‐ylimino)methylphenol with triethylene glycol di‐p‐tosylate, have been synthesized. Reaction of Ru(bpy)2Cl2·2H2O with BL, respectively, afforded four bimetallic complexes [(bpy)2RuBL1−4Ru(bpy)2]4+ as [PF6] salts. Electrochemistry of these complexes is consistent with one RuII‐based oxidation and several ligand‐based reductions. These complexes show metal‐to‐ligand charge transfer absorption at 439‐452 nm and emission at 570‐597 nm.  相似文献   

14.
The new complexes K2[Ni(Hheo)2], K2[Cu(Hheo)2]·H2O, K2[Ni(Hhpo)2]·H2O, K2[M(Hhpo)2]·0.5H2O (M = Cu, Pd) and K2[Cu2(hpo)2·0.5H2O, where H3heo = N-(2-hydroxyethyl)oxamide and H3hpo = N-(3-hydroxypropyl)oxamide, have been prepared. Several synthetic routes were investigated and the complexes were characterized by analyses, conductivity measurements, thermogravimetry, magnetic susceptibility and spectroscopy (i.r. and far i.r., diffuse reflectance u.v.). Monomeric square planar structures are found for the [M(Hheo)2]2− and [M(Hhpo)2]2− complex anions, while the hpo3− Cu(II) complex appears to be a square planar dimer. The doubly deprotonated Hheo2− and Hhpo2− ions exhibit a bidentate N(secondary amide), N′(tertiary amide)-coordination with the OH-group remaining uncoordinated, while the triply deprotonated hpo3− ion behaves as a bridging N(secondary amide), N′(tertiary amide), O(deprotonated) ligand, while two Cu(II) centres are bridged by two alkoxide-O atoms. The vibrational analysis of the dehydrated complexes is carried out, using NH/ND, OH/OD, 58Ni/62Ni and 63Cu/65Cu substitutions.  相似文献   

15.
Novel heteropolymetallic architectures have been built by integrating Pd, Au and Ag systems. The dinuclear [(CNC)(PPh3)Pd-G11M(PPh3)](ClO4) (G11M=Au ( 3 ), Ag ( 4 ); CNC=2,6-diphenylpyridinate) and trinuclear [{(CNC)(PPh3)Pd}2G11M](ClO4) (G11M=Au ( 6 ), Ag ( 5 )) complexes have been accessed or isolated. Structural and DFT characterization unveil striking interactions of one of the aryl groups of the CNC ligand(s) with the G11M center, suggesting these complexes constitute models of transmetallation processes. Further analyses allow to qualitatively order the degree of transfer, proving that Au promotes the highest one and also that Pd systems favor higher degrees than Pt. Consistently, Energy Decomposition Analysis calculations show that the interaction energies follow the order Pd−Au > Pt−Au > Pd−Ag > Pt−Ag. All these results offer potentially useful ideas for the design of bimetallic catalytic systems.  相似文献   

16.
Interaction of R n M-derivatives of 4-nitrophenol and thiophenol (R n M= PhHG, PPh3Au, Ph3Sn, Ph4Sb) with a set of inorganic and organic anions (Cl, Br, I, CN, [PhOCO], [4-NO2C6H4OCO]) was studied by IR and electronic spectroscopy in solvents with different polarities and coordinating properties (C6H6, CH2Cl2, DMSO). The dependence of the character of the interaction with the anions on the nature of the metal atom and heteroatom, the type of anions and the nature of the media was analyzed. Such interaction leads to ion-molecular complexes, and also to dissociation of the X-M bond (X = O, S, M = Au, Hg. Sb) with formation of the (4-NO2C6H4X) anion even in weakly polar media. Only in the case of 4-NO2C6H4OSnPh3 does the reaction stop at the stage of complex formation. In other cases the role of complex formation with anions is less than with neutral coordinating reagents.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1838–1841, July, 1996.  相似文献   

17.
We have studied the effect of substituent R on the rate and mechanism of thermal decomposition of copper(II) complexes with L-α-amino acids anions H2NCH(R)COO?. The homolytic decomposition rate increases in the series of CuL2 complexes with alanine, glycine, valine, isoleucine, leucine, phenylalanine, and serine. Intramolecular redox formation of ·+CuGly cation-radical upon reduction of Cu(II) to Cu(I) and oxidation of H2NCH2COO? into H2NCH2COO· carboxylamine radical is the primary stage of heat-induced decomposition.  相似文献   

18.
The reaction of gold(III) neutral complexes AuBr(CN)2(N–N) {N–N = 2,2′-bipyridine (bpy), 5,5′-dimethyl-2,2′-bipyridine (Me2bpy), 1,10-phenanthroline (phen)} with a stoichiometric amount of K[AuCl4] · 2H2O in nitromethane at room temperature led to the formation of 1:1 electrolytes which were characterized by NMR and IR spectroscopy, conductivity measurements, elemental analyses and X-ray diffraction. Both the anions and the cations of these salts are singly charged square-planar Au(III) complexes and the cations have general formula [AuCl2(N–N)]+. A hypothesis on the possible reaction mechanisms is presented to give an explanation for the formation of the reaction products.  相似文献   

19.
Orange crystals of bis(acetonitrile‐κN)bis[N,N‐bis(diphenylphosphanyl)ethanamine‐κ2P,P′]iron(II) tetrabromidoferrate(II), [Fe(CH3CN)2(C26H25NP2)2][FeBr4], (I), and red crystals of bis(acetonitrile‐κN)bis[N,N‐bis(diphenylphosphanyl)ethanamine‐κ2P,P′]iron(II) μ‐oxido‐bis[tribromidoferrate(III)], [Fe(CH3CN)2(C26H25NP2)2][Fe2Br6O], (II), were obtained from the same solution after prolonged exposure to atmospheric oxygen, resulting in partial oxidation of the [FeBr4]2− anion to the [Br3FeOFeBr3]2− anion. The asymmetric unit of (I) consists of three independent cations, one on a general position and two on inversion centres, with two anions, required to balance the charge, located on general positions. The asymmetric unit of (II) consists of two independent cations and two anions, all on special positions. The geometric parameters within the coordination environments of the cations do not differ significantly, with the major differences being in the orientation of the phenyl rings on the bidentate phosphane ligand. The ethyl substituent in the cation of (II) and the Br atoms in the anions of (II) are disordered. The P—Fe—P bite angles represent the smallest angles reported to date for octahedral FeII complexes containing bidentate phosphine ligands with MeCN in the axial positions, ranging from 70.82 (3) to 70.98 (4)°. The average Fe—Br bond distances of 2.46 (2) and 2.36 (2) Å in the [FeBr4]2− and [Br3FeOFeBr3]2− anions, respectively, illustrate the differences in the Fe oxidation states.  相似文献   

20.
As a H2O2 generator, a 2e oxygen reduction reaction active electrocatalyst plays an important role in the advanced oxidation process to degrade organic pollutants in sewage. To enhance the tendency of NiCo2S4 towards the 2e reduction reaction, N atoms are doped in its structure and replace S2−. The result implies that this weakens the interaction between NiCo2S4 and OOH*, suppresses O−O bond breaking and enhances H2O2 selectivity. This electrocatalyst also shows photothermal effect. Under photothermal heating, H2O2 produced by the oxidation reduction reaction can decompose and releaseOH, which degrades organic pollutants through the advanced oxidation process. Photothermal effect induced by the advance oxidation process shows obvious advantages over the traditional Fenton reaction, such as wide pH adaptation scope and low secondary pollutant due to its Fe2+ free character. With Zn as anode and the electrocatalyst as cathode material, a Zn−O2 battery is assembled. It achieves electricity generation and photothermal effect induced by the advance oxidation process simultaneously.  相似文献   

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