The host–guest chemistry of metal–organic frameworks (MOFs) has enabled the derivation of numerous new functionalities. However, intrinsically chiral MOFs (CMOFs) with helical channels have not been ...used to realize crystalline circularly polarized luminescence (CPL) materials. Herein, enantiomeric pairs of MOF crystals are reported, where achiral fluorophores adhere to the inner surface of helical channels via biology‐like H‐bonds and hence inherit the helicity of the host MOFs, eventually amplifying the luminescence dissymmetry factor (glum) of the host l/d‐CMOF (±1.50 × 10−3) to a maximum of ±0.0115 for the composite l/d‐CMOF⊃fluorophores. l/d‐CMOF⊃fluorophores in pairs generate bright color‐tunable CPL and almost ideal white CPL (0.33, 0.32) with a record‐high photoluminescence quantum yield of ≈30%, which are further assembled into a white circularly polarized light‐emitting diode. The present strategy opens a new avenue for propagating the chirality of MOFs to realize universal chiroptical materials.
Achiral‐aggregation‐caused quenching fluorophores are helically arranged in the chiral channels of enantiomeric metal–organic frameworks (MOFs) for color‐tunable and bright white circularly polarized luminescence (photoluminescence quantum yield (PLQY), ≈33%). The experimental results indicate that the helical arrangement is superior to the ET process in the amplification of the luminescence dissymmetry factor. Also, the MOF‐based composites are assembled into a bright white circularly polarized light‐emitting diode (PLQY, ≈30%).
Metal–organic frameworks (MOFs) have recently emerged as a type of uniformly and periodically atom‐distributed precursor and efficient self‐sacrificial template to fabricate hierarchical ...porous‐carbon‐related nanostructured functional materials. For the first time, a Cu‐based MOF, i.e., Cu‐NPMOF is used, whose linkers contain nitrogen and phosphorus heteroatoms, as a single precursor and template to prepare novel Cu3P nanoparticles (NPs) coated by a N,P‐codoped carbon shell that is extended to a hierarchical porous carbon matrix with identical uniform N and P doping (termed Cu3P@NPPC) as an electrocatalyst. Cu3P@NPPC demonstrates outstanding activity for both the hydrogen evolution and oxygen reduction reaction, representing the first example of a Cu3P‐based bifunctional catalyst for energy‐conversion reactions. The high performances are ascribed to the high specific surface area, the synergistic effects of the Cu3P NPs with intrinsic activity, the protection of the carbon shell, and the hierarchical porous carbon matrix doped by multiheteroatoms. This strategy of using a diverse MOF as a structural and compositional material to create a new multifunctional composite/hybrid may expand the opportunities to explore highly efficient and robust non‐noble‐metal catalysts for energy‐conversion reactions.
Cu3P nanoparticles coated by a N,P‐codoped carbon shell (hierarchical porous carbon matrix) are prepared using a novel Cu‐based metal–organic framework (MOF) containing dual linkers as a template and single precursor. The Cu3P@NPPC catalyst demonstrates a high specific surface area and affords remarkable bifunctional electrocatalytic performance for hydrogen evolution reaction and oxygen reduction reaction with long‐term durability for both reactions.
Chiral assembly and asymmetric synthesis are critically important for the generation of chiral metal clusters with chiroptical activities. Here, a racemic mixture of K(CH3OH)2(18‐crown‐6)+Cu5(StBu)6− ...(1⋅CH3OH) in the chiral space group was prepared, in which the chiral red‐emissive anionic Cu5(StBu)6− cluster was arranged along a twofold screw axis. Interestingly, the release of the coordinated CH3OH of the cationic units turned the chiral 1⋅CH3OH crystal into a mesomeric crystal K(18‐crown‐6)+Cu5(StBu)6− (1), which has a centrosymmetric space group, by adding symmetry elements of glide and mirror planes through both disordered Cu5(StBu)6− units. The switchable chiral/achiral rearrangement of Cu5(StBu)6− clusters along with the capture/release of CH3OH were concomitant with an intense increase/decrease in luminescence. We also used cationic chiral amino alcohols to induce the chiral assembly of a pair of enantiomers, d/l‐valinol(18‐crown‐6)+Cu5(StBu)6− (d/l‐Cu5V), which display impressive circularly polarized luminescence (CPL) in contrast to the CPL‐silent racemic mixture of 1⋅CH3OH and mesomeric 1.
Hydrogen‐bonding interactions dictate the switchable chiral/achiral stacking of red‐emissive anionic copper clusters. Racemic and mesomeric crystals containing these anions do not show circularly polarized luminescence (CPL). However, homochiral crystals prepared from chiral amino acids, which act as chiral hydrogen‐bond donors, are CPL active.
A covalent organic framework integrating naphthalenediimide and triphenylamine units (NT‐COF) is presented. Two‐dimensional porous nanosheets are packed with a high specific surface area of 1276 m2 ...g−1. Photo/electrochemical measurements reveal the ultrahigh efficient intramolecular charge transfer from the TPA to the NDI and the highly reversible electrochemical reaction in NT‐COF. There is a synergetic effect in NT‐COF between the reversible electrochemical reaction and intramolecular charge transfer with enhanced solar energy efficiency and an accelerated electrochemical reaction. This synergetic mechanism provides the key basis for direct solar‐to‐electrochemical energy conversion/storage. With the NT‐COF as the cathode materials, a solar Li‐ion battery is realized with decreased charge voltage (by 0.5 V), increased discharge voltage (by 0.5 V), and extra 38.7 % battery efficiency.
A covalent organic framework functionalized with triphenylamine and naphthalenediimide units was used as a cathode. It could synergize photoinduced charge transfer with reversible electrochemical (de)lithiation processes. This leads to decreased charge voltage (by 0.5 V), increased discharge voltage (by 0.5 V), and an extra 38.7 % battery efficiency under illumination.
Oxidizing CH4 into liquid products with O2 under mild conditions still mainly relies on metal catalysis. We prepared a series of sulfone‐modified conjugated organic polymers and found that the ...catalyst with proper SVI content (0.10) could drive O2→H2O2→⋅OH to oxidize CH4 into CH3OH and HCOOH directly and efficiently at room temperature under light irradiation. Experimental results showed that after 4 h reaction, decomposition rate and residual amounts of H2O2 were 81.21 % and 4.83 mmol gcat−1 respectively, and CH4 conversion rate was 22.81 %. Mechanism studies revealed that illumination could induce the homolytic dissociation of S=O bonds on catalyst to produce oxygen and sulfur radicals, where the ⋅O could adsorb and activate CH4, and the ⋅S could supply electrons for 1O2 to generate H2O2 and then for decomposing the H2O2 into ⋅OH timely to oxidize CH4. This research provided a novel organic catalysis approach for oxygen activation and utilization.
In a process of methane conversion photocatalyzed by the sulfone‐decorated conjugated organic polymer, S‐CTTP, light irradiation first induced the homolytic dissociation of S=O bonds in sulfone groups on the catalyst surface to generate free radicals. The radicals drive efficient conversion of 1O2 to H2O2 and then ⋅OH, for selective oxidation of adsorbed CH4 into CH3OH and HCOOH.
Atomically precise enantiomeric metal clusters are scarce, and copper(I) alkynyl clusters with intense circularly polarized luminescence (CPL) responses have not been reported. A pair of chiral ...alkynyl ligands, (R/S)‐2‐diphenyl‐2‐hydroxylmethylpyrrolidine‐1‐propyne (abbreviated as R/S‐DPM) we successfully prepared and single crystals were characterized of optically pure enantiomeric pair of atomically‐precise copper(I) clusters, Cu14(R/S‐DPM)8(PF6)6 (denoted as R/S‐Cu14), which feature bright red luminescence and CPL with a high luminescence anisotropy factor (glum). A dilute solution containing R/S‐Cu14 was nonluminescent and CPL inactive at room temperature. Crystallization‐ and aggregation‐induced emission (CIE and AIE, respectively) contribute to the triggering of the CPL of R/S‐Cu14 in the crystalline and aggregated states. Their AIE behavior and good biocompatibility indicated applications of these copper(I) clusters in cell imaging in HeLa and NG108‐15 cells.
Atomically precise chiral CuI alkynyl nanoclusters R/S‐Cu14 with inherent chirality were synthesized for the first time. Crystallization‐ and aggregation‐induced emission (CIE and AIE, respectively) trigger circularly polarized luminescence (CPL) with an unprecedented luminescence anisotropy factor (glum).
Silver chalcogenolate cluster assembled materials (SCAMs) are a category of promising light‐emitting materials the luminescence of which can be modulated by variation of their building blocks ...(cluster nodes and organic linkers). The transformation of a singly emissive Ag12(SBut)8(CF3COO)4(bpy)4n (Ag12bpy, bpy=4,4′‐bipyridine) into a dual‐emissive (Ag12(SBut)6(CF3COO)6(bpy)3)n (Ag12bpy‐2) via cluster‐node isomerization, the critical importance of which was highlighted in dictating the photoluminescence properties of SCAMs. Moreover, the newly obtained Ag12bpy‐2 served to construct visual thermochromic Ag12bpy‐2/NH2 by a mixed‐linker synthesis, together with dichromatic core–shell Ag12bpy‐2@Ag12bpy‐NH2‐2 via solvent‐assisted linker exchange. This work provides insight into the significance of metal arrangement on physical properties of nanoclusters.
Tandem varying of Ag cluster structure and tuning mixed linkers in a stepwise fashion are used to achieve dual‐emitting homogeneous and core–shell silver chalcogenolate cluster assembled materials. The arrangements of silver in the cluster are demonstrated to play a fundamentally important role in luminescence.
Circularly polarized luminescence (CPL) switches have attracted widespread attention due to their potential applications in advanced information technologies. However, the design and fabrication of ...solid‐state multiple‐responsive CPL switches remain challenging. Here, through self‐assembly of chiral metal‐organic frameworks (MOFs) and perovskite nanocrystals (NCs), a pair of crystalline enantiomeric (P)‐(+)/(M)‐(−)‐EuMOF⊃MAPbX3 (MA = CH3NH3+, X = Cl−, Br−, I−) adducts is prepared, where the achiral MAPbBr3 perovskite NCs embedded into chiral MOFs inherit the chirality of host MOFs by host‐guest EuBr and PbO coordination bonds, which is demonstrated by synchrotron‐radiation‐based X‐ray absorption spectroscopy. The chiral adducts show enhanced photoluminescence quantum yield (PLQY), good thermal stability of CPL in air, and photoswitchable CPL properties upon altering different UV irradiation. Based on two chiral emission centers and their different characteristics, reversible CPL switches are realized upon a diversity of external stimuli, for example, chemicals (water /CH3NH3Br solution) or temperatures (room temperature/high temperature). Benefiting from the extraordinary stimuli‐responsive and highly reversible switchable CPL, multiple information encryptions and decryptions integrated with CPL, together with a chiroptical logic gate are successfully designed. This work opens a new avenue to generally fabricate solid‐state CPL composite materials and develops new applications based on switchable CPL.
Achiral perovskite nanocrystals (NCs) are embedded in homochiral metal‐organic frameworks (MOFs) for color‐tunable circularly polarized luminescence (CPL) without any ligand passivation. Experimental results indicate that MAPbBr3 NCs adopted a chiral packing in enantiomeric MOFs by EuBr and PbO bonds. The CPL of composites possesses the multiple external‐stimulate responsive reversibility.
The Mn
Cl
mode of red emissive (C
NOH
)
Mn
Cl
·C
H
OH under thermal treatment will be cleaved into MnCl
in the green emissive (C
NOH
)
MnCl
with the departure of ethanol. The rapid conversion of ...luminescence from red to green provides new insight into the luminescence origin and thermal stability of organic-inorganic metal halide hybrids.
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