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Photocatalytic oxygen reduction reactions and water oxidation reactions are extremely promising green approaches for massive H2O2 production. Nonetheless, constructing effective photocatalysts for H2O2 generation is critical and still challenging. Since the network topology has significant impacts on the electronic properties of two dimensional (2D) polymers, herein, for the first time, we regulated the H2O2 photosynthetic activity of 2D covalent organic frameworks (COFs) by topology. Through designing the linking sites of the monomers, we synthesized a pair of novel COFs with similar chemical components on the backbones but distinct topologies. Without sacrificial agents, TBD‐COF with cpt topology exhibited superior H2O2 photoproduction performance (6085 and 5448 μmol g−1 h−1 in O2 and air) than TBC‐COF with hcb topology through the O2‐O2⋅−‐H2O2, O2‐O2⋅−‐O21‐H2O2, and H2O‐H2O2 three paths. Further experimental and theoretical investigations confirmed that during the H2O2 photosynthetic process, the charge carrier separation efficiency, O2⋅− generation and conversion, and the energy barrier of the rate determination steps in the three channels, related to the formation of *OOH, *O21, and *OH, can be well tuned by the topology of COFs. The current study enlightens the fabrication of high‐performance photocatalysts for H2O2 production by topological structure modulation. [ABSTRACT FROM AUTHOR]

The catalytic performance for electrocatalytic CO2 reduction reaction (CO2RR) depends on the binding strength of the reactants and intermediates. Covalent organic frameworks (COFs) have been adopted to catalyze CO2RR, and their binding abilities are tuned via constructing donor‐acceptor (DA) systems. However, most DA COFs have single donor and acceptor units, which caused wide‐range but lacking accuracy in modulating the binding strength of intermediates. More elaborate regulation of the interactions with intermediates are necessary and challenge to construct high‐efficiency catalysts. Herein, the three‐component COF with D‐A‐A units was first constructed by introducing electron‐rich diarylamine unit, electron‐deficient benzothiazole and Co‐porphyrin units. Compared with two‐component COFs, the designed COF exhibit elevated electronic conductivity, enhanced reducibility, high efficiency charge transfer, further improving the electrocatalytic CO2RR performance with the faradic efficiency of 97.2 % at −0.8 V and high activity with the partial current density of 27.85 mA cm−2 at −1.0 V which exceed other two‐component COFs. Theoretical calculations demonstrate that catalytic sites in three‐component COF have suitable binding ability of the intermediates, which are benefit for formation of *COOH and desorption of *CO. This work offers valuable insights for the advancement of multi‐component COFs, enabling modulated charge transfer to improve the CO2RR activity. [ABSTRACT FROM AUTHOR]

Aiming at the construction of novel stimuli‐responsive fluorescent system with precisely tunable emissions, the typical 9,14‐diphenyl‐9,14‐dihydrodibenzo[a, c]phenazine (DPAC) luminogen with attractive vibration‐induced emission (VIE) behavior has been introduced into [2]rotaxane as a stopper. Taking advantage of their unique dual stimuli‐responsiveness towards solvent and anion, the resultant [2]rotaxanes reveal both tunable VIE and switchable circularly polarized luminescence (CPL). Attributed to the formation of mechanical bonds, DPAC‐functionalized [2]rotaxanes display interesting VIE behaviors including white‐light emission upon the addition of viscous solvent, as evaluated in detail by femtosecond transient absorption (TA) spectra. In addition, ascribed to the regulation of chirality information transmission through anion‐induced motions of chiral wheel, the resolved chiral [2]rotaxanes reveal unique switchable CPL upon the addition of anion, leading to significant increase in the dissymmetry factors (glum) values with excellent reversibility. Interestingly, upon doping the chiral [2]rotaxanes in stretchable polymer, the blend films reveal remarkable emission change from white light to light blue with significant 6.5‐fold increase in glum values up to −0.035 under external tensile stresses. This work provides not only a new design strategy for developing molecular systems with fluorescent tunability but also a novel platform for the construction of smart chiral luminescent materials for practical use. [ABSTRACT FROM AUTHOR]

Weak adsorption of gas reactants and strong binding of intermediates present a significant challenge for most transition metal oxides, particularly in the realm of CO2 photoreduction. Herein, we demonstrate that the adsorption can be fine‐tuned by phase engineering of oxide catalysts. An oxygen vacancy mediated topological phase transition in Ni‐Co oxide nanowires, supported on a hierarchical graphene aerogel (GA), is observed from a spinel phase to a rock‐salt phase. Such in situ phase transition empowers the Ni‐Co oxide catalyst with a strong internal electric field and the attainment of abundant oxygen vacancies. Among a series of catalysts, the in situ transformed spinel/rock‐salt heterojunction supported on GA stands out for an exceptional photocatalytic CO2 reduction activity and selectivity, yielding an impressive CO production rate of 12.5 mmol g−1 h−1 and high selectivity of 96.5 %. This remarkable performance is a result of the robust interfacial coupling between two topological phases that optimizes the electronic structures through directional charge transfer across interfaces. The phase transition process induces more Co2+ in octahedral site, which can effectively enhance the Co‐O covalency. This synergistic effect balances the surface activation of CO2 molecules and desorption of reaction intermediates, thereby lowering the energetic barrier of the rate‐limiting step. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have been utilized for catalyzing the reduction of carbon dioxide (CO2RR) due to their atomic metal centers and controllable pore channels, which are facilitated by different covalent bonds. However, the exploration of boron‐based linkages in these catalytic COFs has been limited owing to potential instability. Herein, we present the construction of boronic ester‐linked COFs through nucleophilic substitution reactions in order to catalyze the CO2RR. The inclusion of abundant fluorine atoms within the frameworks enhances their hydrophobicity and subsequently improves water tolerance and chemical stability of COFs. The content of boron atoms in the COF linkages was carefully controlled, with COFs featuring a higher density of boron atoms exhibiting increased electronic conductivity, enhanced reductive ability, and stronger binding affinity towards CO2. Consequently, these COFs demonstrate improved activity and selectivity. The optimized COFs achieve the highest activity, achieving a turnover frequency of 1695.3 h−1 and a CO selectivity of 95.0 % at −0.9 V. Operando synchrotron radiation measurements confirm the stability of Co (II) atoms as catalytically active sites. By successfully constructing boronic ester‐linked COFs, we not only address potential instability concerns but also achieve exceptional catalytic performance for CO2RR. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have attracted considerable attention as adsorbents for capturing and separating gold from electronic wastes. To enhance the binding capture efficiency, constructing hydrogen‐bond nanotraps along the pore walls was one of the most widely adopted approaches. However, the development of absorbing skeletons was ignored due to the weak binding ability of the gold salts (Au). Herein, we demonstrated skeleton engineering to construct highly efficiently absorbs for Au capture. The strong electronic donating feature of diarylamine units enhanced the electronic density of binding sites (imine‐linkage) and thus resulted in high capacities over 1750 mg g−1 for all three COFs. Moreover, the absorbing performance was further improved via the ionization of diarylamine units. The ionic COF achieved 90 % of the maximal adsorption capacity, 1.63 times of that from the charge‐neutral COF within ten minutes, and showed remarkable uptakes of 1834 mg g−1, exceptional selectivity (97.45 %) and cycling stability. The theoretical calculation revealed the binding sites altering from imine bonds to ionic amine sites after ionization of the frameworks, which enabled to bind the AuCl4− via coulomb force and contributed to enhanced absorbing kinetics. This work inspires us to design molecular/ionic capture based on COFs. [ABSTRACT FROM AUTHOR]

H2O2 is a significant chemical widely utilized in the environmental and industrial fields, with growing global demand. Without sacrificial agents, simultaneous photocatalyzed H2O2 synthesis through the oxygen reduction reaction (ORR) and water oxidation reaction (WOR) dual channels from seawater is green and sustainable but still challenging. Herein, two novel thiophene‐containing covalent organic frameworks (TD‐COF and TT‐COF) were first constructed and served as catalysts for H2O2 synthesis via indirect 2e− ORR and direct 2e− WOR channels. The photocatalytic H2O2 production performance can be regulated by adjusting the N‐heterocycle modules (pyridine and triazine) in COFs. Notably, with no sacrificial agents, just using air and water as raw materials, TD‐COF exhibited high H2O2 production yields of 4060 μmol h−1 g−1 and 3364 μmol h−1 g−1 in deionized water and natural seawater, respectively. Further computational mechanism studies revealed that the thiophene was the primary photoreduction unit for ORR, while the benzene ring (linked to the thiophene by the imine bond) was the central photooxidation unit for WOR. The current work exploits thiophene‐containing COFs for overall photocatalytic H2O2 synthesis via ORR and WOR dual channels and provides fresh insight into creating innovative catalysts for photocatalyzing H2O2 synthesis. [ABSTRACT FROM AUTHOR]

Two‐dimensional covalent organic frameworks (2D COFs) are often employed for electrocatalytic systems because of their structural diversity. However, the efficiency of atom utilization is still in need of improvement, because the catalytic centers are located in the basal layers and it is difficult for the electrolytes to access them. Herein, we demonstrate the use of 1D COFs for the 2e− oxygen reduction reaction (ORR). The use of different four‐connectivity blocks resulted in the prepared 1D COFs displaying good crystallinity, high surface areas, and excellent chemical stability. The more exposed catalytic sites resulted in the 1D COFs showing large electrochemically active surface areas, 4.8‐fold of that of a control 2D COF, and thus enabled catalysis of the ORR with a higher H2O2 selectivity of 85.8 % and activity, with a TOF value of 0.051 s−1 at 0.2 V, than a 2D COF (72.9 % and 0.032 s−1). This work paves the way for the development of COFs with low dimensions for electrocatalysis. [ABSTRACT FROM AUTHOR]

Single‐electron transfer (SET) oxidation of ionic hypervalent complexes, in particular alkyltrifluoroborates (Alkyl‐BF3−) and alkylbis(catecholato)silicates (Alkyl‐Si(cat)2−), have contributed substantially to alkyl radical generation compared to alkali or alkaline earth organometallics because of their excellent activity–stability balance. Herein, another proposal is reported by using neutral metalloid compounds, Alkyl‐GeMe3, as radical precursors. Alkyl‐GeMe3 shows comparable activity to that of Alkyl‐BF3− and Alkyl‐Si(cat)2− in radical addition reactions. Moreover, Alkyl‐GeMe3 is the first successful group 14 tetraalkyl nucleophile in nickel‐catalyzed cross‐coupling. Meanwhile, the neutral nature of these organogermanes offset the limitation of ionic precursors in purification and derivatization. A preliminary mechanism study suggests that an alkyl radical is generated from a tetraalkylgermane radical cation with the assistance of a nucleophile, which may also result in the development of more non‐ionic alkyl radical precursors with a metalloid center. [ABSTRACT FROM AUTHOR]

Despite rapid progress over the past decade, most polycondensation systems even upon a small structural variation of the building units eventually result in amorphous polymers other than the desired crystalline covalent organic frameworks. This synthetic dilemma is a central and challenging issue of the field. Here we report a novel approach based on module‐patterned polymerization to enable efficient and designed synthesis of crystalline porous polymeric frameworks. This strategy features a wide applicability to allow the use of various knots of different structures, enables polycondensation with diverse linkers, and develops a diversity of novel crystalline 2D polymers and frameworks, as demonstrated by using the C=C bond‐formation polycondensation reaction. The new sp2‐carbon frameworks are highly emissive and enable up‐conversion luminescence, offer low band gap semiconductors with tunable band structures, and achieve ultrahigh charge mobilities close to theoretically predicted maxima. [ABSTRACT FROM AUTHOR]

Locking nonequilibrium shapes of liquids into targeted architectures by interfacial jamming of nanoparticles is an emerging area in material science. 5,10,15,20‐tetrakis(4‐sulfonatophenyl) porphyrin (H6TPPS) shows three different aggregation states that present an absorption imaging platform to monitor the assembly and jamming of supramolecular polymer surfactants (SPSs) at the liquid/liquid interface. The interfacial interconversion of H6TPPS, specifically H4TPPS2− dissolved in water, from J‐ to an H‐aggregation was induced by strong electrostatic interactions with amine‐terminated polystyrene dissolved in toluene at the water/toluene interface. This resulted in color‐tunable liquids due to interfacial jamming of the SPSs formed between H4TPPS2− and amine‐terminated polystyrene. However, the formed SPSs cannot lock in nonequilibrium shapes of liquids. In addition, a self‐wrinkling behavior was observed when amphiphilic triblock copolymers of PS‐block‐poly(2‐vinylpyridine)‐block‐poly(ethylene oxide) were used to interact with H4TPPS2−. Subsequently, the SPSs formed can lock in nonequilibrium shapes of liquids. [ABSTRACT FROM AUTHOR]

Supramolecular cages/vesicles in biology display sophisticated structures and functions by utilizing a few types of protein subunit quasi‐equivalently at distinct geometrical locations. However, synthetic supramolecular cages still lack comparable complexity to reach the high levels of functionality found in natural systems. Herein we report the self‐assembly of giant pentagonal supramolecular prisms (molecular weight >50 kDa) with tetratopic pyridinyl subunits serving different geometrical roles within the structures, and their packing into a novel superstructure with unexpected three‐fold rotational symmetry in a single two‐dimensional layer of crystalline state. The formation of these complicated structures is controlled by both the predetermined angles of the ligands and the mismatched structural tensions created from the multi‐layered geometry of the building blocks. Such a self‐assembly strategy is extensively used by viruses to increase the volume and complexity of capsids and would provide a new approach to construct highly sophisticated supramolecular architectures. [ABSTRACT FROM AUTHOR]

Interpenetration in metal–organic frameworks (MOFs) is an intriguing phenomenon with significant impacts on their properties, and functional applications. Herein, we show that a 7‐fold interpenetrated MOF (1) is transformed into an 8‐fold interpenetrated MOF by the loss of DMF in a single‐crystal‐to‐single‐crystal manner. This is accompanied by a giant enhancement of the second harmonic generation (SHG ca. 125 times) and two‐photon photoluminescence (ca. 14 times). The strengthened π–π interaction between the individual diamondoid networks and intensified oscillator strength of the molecules aid the augment of dipole moments and boost the nonlinear optical conversion efficiency. Large positive and negative thermal expansions of 1 occur at 30–150 °C before the loss of DMF. These results offer an avenue to manipulate the NLO properties of MOFs using interpenetration and provide access to tunable single‐crystal NLO devices. [ABSTRACT FROM AUTHOR]

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