Donglin Jiang

National University of Singapore | NUS · Department of Chemistry

Attempts to develop photocatalysts for hydrogen production from water usually result in low efficiency. Here we report the finding of photocatalysts by integrated interfacial design of stable covalent organic frameworks. We predesigned and constructed different molecular interfaces by fabricating ordered or amorphous π skeletons, installing ligatin...

The dream to prepare well-defined materials drives the methodological evolution for molecular synthesis, structural control and materials manufacturing. Among various methods, chemical approaches to design, synthesize, control and engineer small molecules, polymers and networks offer the fundamental strategies. Merging covalent bonds and non-covale...

Assembling molecular catalytic centers into crosslinked networks is widely used to fabricate heterogeneous catalysts but they often suffer loss in activity and selectivity accompanied by unclear causes. Here we report a strategy for the construction of heterogeneous catalysts to induce activity and selectivity by bottom‐up introduction of segregate...

To optimize the optical and optoelectronic functionalities of two-dimensional (2D) covalent organic frameworks (COFs), detailed properties of emissive and nonradiative pathways after photoexcitation need to be elucidated and linked to particular structural designs. Here, we use transient absorption (TA) spectroscopy to study the colloidal suspensio...

Despite a rapid progress over the past decade, most polycondensation systems even upon a small structural variation of building units eventually result in amorphous polymers other than 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 mod...

A new topology diagram was developed for the efficient and designed synthesis of 2D polymers and open frameworks, which led to the creation of novel 2D sp²-carbon materials via a C=C bond-formation reaction. The sp²-carbon frameworks are highly emissive and exhibit two-photon up-conversion luminescence, create novel 2D semiconductors with low band...

Progress over the past decades in water confinement has generated a variety of polymers and porous materials. However, most studies are based on a preconception that small hydrophobic pores eventually repulse water molecules, which precludes the exploration of hydrophobic microporous materials for water confinement. Here, we demonstrate water confi...

Most organic/polymeric semiconductors are p-type semiconductors, whereas their n-type versions are limited in both availability and carrier mobility. How to develop high-rate n-type organic/polymeric semiconductors remains challenging. Here, we report an approach to high-rate n-type semiconductors via topology-directed polycondensation of conventio...

Hydroxide anion transport is essential for alkaline fuel cells, but hydroxide anion has an inherently low conductivity owing to its small diffusion coefficient and high mass. Ordered open channels found in covalent organic frameworks are promising as pathways to enable hydroxide anion transport, but this remains to be explored. Here we report desig...

The ordered π skeletons of covalent organic frameworks make them viable light‐emitting materials but their limited tunability has precluded further implementation. Here we report the synthesis of hydrazone‐linked frameworks which are stable in water, acid, and base, and demonstrate their utility as a platform for light emission. The polygonal backb...

The ordered π skeletons of covalent organic frameworks make them viable light‐emitting materials but their limited tunability has precluded further implementation. Here we report the synthesis of hydrazone‐linked frameworks which are stable in water, acid, and base, and demonstrate their utility as a platform for light emission. The polygonal backb...

Covalent organic frameworks (COFs) are a class of crystalline polymers that integrate organic units into 2D and 3D skeletons to achieve ordered yet extended structures via topology-directed polymerization. Recent progress in chemistry over the past 4 years has greatly raised the ability to design the frameworks to attain fully π-conjugated all sp²...

Condensing benzimidazole units via topology-directed polymerization allows the construction of stable covalent organic frameworks with ordered one-dimensional channels. The walls trigger multiple hierarchical interactions so that the proton networks are locked in the pores via spatial confinement and activated via deprotonation. Ultrafast and stabl...

Polybenzimidazoles are engineering plastics with superb thermal stability and this specificity sparks a wide‐range research to explore proton conducting materials. Nevertheless, they encounter challenging issues owing to phosphoric acid proton carrier leakage and slow proton transport. Here we report a strategy for designing porous polybenzimidazol...

Covalent organic frameworks offer a molecular platform for integrating organic units into periodically ordered yet extended 2D and 3D polymers to create topologically well-defined polygonal lattices and built-in discrete micropores and/or mesopores.

Isomerism is widely observed in chemistry but it has scarce ly been identified in crystalline porous covalent organic frameworks. Herein, we designed and synthesized a series of A 2 B 2 type tetraphenyl benzene monomers (p‐, m‐, and o‐TetPB) which have the para‐, meta, and ortho‐substituted isomeric structures, for the direct construction of isomer...

A strategy was developed for selective growth of isomeric covalent organic frameworks by designing monomer isomers and tuning reaction conditions. Three A2B2 type tetraphenyl benzene monomers (p‐, m‐, and o‐TetPB) afford five different 2D TetPB‐COF isomers that exhibit selective adsorption of vitamin B12 owing to a great difference in their pore sh...

Covalent organic frameworks (COF) are a class of crystalline porous polymer that enables the covalent integration of organic units into periodically ordered skeletons and aligned polygonal pores. This structural feature sets a new polymer platform that enables the design of not only structures but also functions. Especially, primary- and high-order...

ConspectusNature evolves fascinating molecular pores to achieve unique biological functions based on a single pore or channel as observed for aquaporins and ion channels. An artificial system, on the other hand, explores porous structures to construct dense pores in materials. Progress in chemistry over the past century has greatly improved our cap...

Heterogeneous catalysts offer a cyclable platform for exploring efficient transformation systems, and their promising applications underpin a broad research interest. Covalent organic frameworks (COFs) are a class of crystalline porous networks that can integrate organic units into ordered skeletons and pores, offering an insoluble and robust platf...

Covalent organic frameworks (COFs) enable precise reticulation of organic building units into extended 2D and 3D open networks using strong covalent bonds to constitute predesignable topologies and tunable pore structures, presenting an emerging class of crystalline porous polymers. Although rapid progress and substantial achievements in COF chemis...

Transformation of carbon dioxide to high value‐added chemicals becomes a significant challenge for clean energy study. Here we developed a stable and conductive covalent organic framework for electrocatalytic carbon dioxide reduction to carbon monoxide in aqueous solution. The cobalt(II) phthalocyanine catalysts are topologically connected via robu...

Transformation of carbon dioxide to high value‐added chemicals becomes a significant challenge for clean energy study. Here we developed a stable and conductive covalent organic framework for electrocatalytic carbon dioxide reduction to carbon monoxide in aqueous solution. The cobalt(II) phthalocyanine catalysts are topologically connected via robu...

Development of porous materials combining stability and high performance has remained a challenge. This is particularly true for proton-transporting materials essential for applications in sensing, catalysis and energy conversion and storage. Here we report the topology guided synthesis of an imine-bonded (C=N) dually stable covalent organic framew...

Attract to plant lattice growth: Imine‐linked covalent organic frameworks (blue) attract organic building blocks on a 2D x−y surface and model C=C bond formation to create 2D sp² carbon lattices with different topologies (yellow). Frameworks are thus formed that cannot be produced by direct polymerization. The synthesis of such lattices leads to kn...

Here we report a strategy for the synthesis of crystalline porous c ovalent organic frameworks via t opology‐templated polymerization. The template is based on imine‐linked frameworks and their (001) facet s seed the C=C bond formation reaction to constitute 2D sp 2 carbon‐conjugated frameworks. This strategy is applicable to templates with differe...

Covalent organic frameworks (COFs) enable precise integration of various organic building blocks into porous skeletons through topology predesign. Here, we report the first example of COFs by integrating electron withdrawing bromine group onto the skeletons for triboelectric nanogenerators (TENG). The resulting framework exhibits high surface area...

Covalent organic frameworks (COFs) are a class of crystalline porous organic polymers with permanent porosity and highly ordered structures. Unlike other polymers, a significant feature of COFs is that they are structurally predesignable, synthetically controllable, and functionally manageable. In principle, the topological design diagram offers ge...

Durch den Kanal: 1D-Nanokanäle ermöglichen Ionenleitung, wenn die Kanalwände mit einer ionischen Grenzfläche manipuliert werden. Kovalente organische Gerüste können solche 1D-Kanäle mit gewünschten Ionenketten-Zusammensetzungen und -dichten für ultraschnellen Ionentransport erschaffen. Dies führt zu einer exponentiellen Korrelation zwischen Grenzfl...

Here we report a strategy based on covalent organic frameworks for ultrafast ion transport by designing tailor‐made ionic interface to mediate ion motion. We integrate electrolyte chains onto the walls of one‐dimensional channels to construct ionic frameworks via pore surface engineering, so that the ionic interface can be systematically tuned at d...

Two‐dimensional covalent organic frameworks were synthesized in high yields by polycondensation in nonvolatile ionic liquids. The resulting crystallites are highly porous and exhibit exceptional capability of removing bisphenol A from water. The one reported is a general method to synthesize microporous and mesoporous frameworks, it allows to achie...

Der richtige Kanal: Offene 1D‐Kanäle, deren Poren in dreieckiger Form und einer diskreten Größe in kovalenten organischen Gerüsten gestaltet wurden, konnten molekulare Größenunterschiede erkennen. Dieser Befund eröffnet die Möglichkeit, 1D‐Kanäle für den selektiven Transport und die sofortige molekulare Trennung mit unendlicher Selektivität zu nutz...

Covalent organic frameworks (COFs) allow elaborate manufacture of ordered one‐dimensional channels in the crystal. While this makes designing by topology diagram particularly attractive as a tool for assembling straight pores to facilitate mass transport, molecular recognition has been so far inaccessible. We define a superlattice of COFs, by engin...

Production of sustainable and renewable energy is a subject of global importance and is a challenging goal in the fields of chemistry and materials science. This perspective focuses on the use of two sustainable resources on this planet, i.e. water and sunlight, for the produc-tion of green chemical energy — hydrogen. Special interests are directed...

Progress over the past decade in chemistry has showcased a new way to design organic polymers using topology diagram. This strategy enables the covalent integration of organic units into ordered topologies and creates a new polymer form, i.e. covalent organic framework. This is a breakthrough in chemistry because it sets a molecular platform for sy...

Progress over the past decade in chemistry has showcased a new way to design organic polymers using topology diagram. This strategy enables the covalent integration of organic units into ordered topologies and creates a new polymer form, i.e. covalent organic framework. This is a breakthrough in chemistry because it sets a molecular platform for sy...

The aligned one-dimensional channels found in covalent organic frameworks offer a unique space for energy storage. However, physical isolation of sulfur in the channels is not sufficient to prevent the shuttle of lithium-sulfide intermediates that eventually results in a poor performance of lithium-sulfur energy storage. Herein, we report a strateg...

Photo-to-chemical energy conversion requires a systematic and complex molecular design to manage consecutive photochemical processes, including energy harvesting, exciton migration, electron transfer, charge separation, and charge transport. However, such an integrated design remains a substantial challenge. Here, we report a seamless system in man...

Enrichment of radioactive iodine in the waste of nuclear industries threatens the health of humans, and efficient capture of iodine has attracted a great deal of attention in recent years. Porous organic polymers (POPs) and metal-organic frameworks (MOFs), new classes of porous materials, act as outstanding candidate adsorbent materials in this fie...

Covalent organic frameworks enable the topological connection of organic chromophores into π lattices, making them attractive for creating light-emitting polymers that are predesignable for both the primary- and high-order structures. However, owing to linkages, covalent organic frameworks are either unstable or poor luminescent, leaving the practi...

Covalent organic frameworks (COFs) offer ordered π structures that are useful for developing light-emitting materials. However, most COFs are weak in lumines-cence. Here we report the conversion of less emissive COFs into light-emitting materials via a pinpoint surgery on the pore walls. Deprotonation of the N–H bond to form an anionic nitrogen spe...

This chapter focuses on reviewing the design, synthesis, and functions of porous carbons based on the porous organic polymers, by elucidating structural effects of porous organic polymers on resulting porous carbons. Conjugated microporous polymers (CMPs) are a unique class of porous amorphous polymers in which organic units are covalently linked i...

Covalent organic frameworks (COFs) with ordered one-dimensional channels could offer a predesigned pathway for ion motion. However, implanting salts into bare channels of COFs gives rise to a limited ion conductivity. Here, we report the first example of polyelectrolyte COFs by integrating flexible oligo(ethylene oxide) chains onto the pore walls....

Rational design and synthesis of 2D organic–inorganic hybrid materials is important for transformative technological advances for energy storage. Here, a 2D conductive hybrid lamella and its intercalation properties for thin‐film supercapacitors are reported. The 2D organic–inorganic hybrid lamella comprises periodically stacked 2D nanosheets with...

Progress over the past decades in porous materials has exerted great effect on the design of metal-free carbon electrochemical catalysts in fuel cells. The carbon material must combine three functions, i.e., electrical conductivity for electron transport, optimal pores for ion motion, and abundant heteroatom sites for catalysis. Here, an ideal carb...

Conducting layered capacitive materials that utilize interlayer space to store charges usually exhibit higher areal and volumetric capacitive performance than porous carbons as a result of the bulk storage mechanism. Here, an organic-inorganic hybrid conducting layered material is designed through a ‘bottom-up’ strategy, and is synthesized facilely...

Progress in chemistry over the past four decades has generated a variety of porous materials for removing iodine—a radioactive emission accompanying nuclear fission. However, most studies are still based on the notion that entangled pores together with specific binding sites are essential for iodine capture. Here, an unraveled physical picture of i...

Covalent organic frameworks (COFs) are a class of crystalline porous polymer that is structurally predesignable and synthetically controllable at both levels of primary and high-order structures. Topological design diagram in conjunction with geometry matching of monomers enables the atomically precise integration of organic units into periodically...

Zirconium-based metal−organic frameworks (Zr-MOFs) exhibit great structural tunability and outstanding chemical sta-bility, rendering them promising candidates for a wide range of practical applications. In this work, we synthesized a series of isostructural PCN-224 analogues functionalized by ethyl, bromo, chloro, and fluoro groups on the porphyri...

Organic polysulfides are linear sulfur chains (R–Sn–R, n ≥ 2) capped with organic moieties, and are appealing cathode materials in lithium batteries. The theoretical capacity of polysulfides essentially relies on the length of the sulfur chains; long-chain polysulfides could store more charges than short-chain polysulfides. Herein, we report the su...

Using porous materials to cope with environmental issues is promising but remains a challenge especially for removing the radioactive vapor wastes in fission because of harsh adsorption conditions. Here we report a new stable covalent organic framework (COF) as a porous platform for removing iodine vapor - a major radioactive fission waste. The thr...

Here we describe a general strategy based on template pyrolysis for converting conventional covalent organic frameworks into high-performance carbons, which combine conductivity, microporosity and heteroatom density, thus casting a distinct...

A highly redox-active building block, bicarbazole, is developed as a monomer for designing crystalline porous covalent organic frameworks and is successfully integrated to the vertices of microporous tetragonal frameworks, leading...

Conjugated covalent networks Although graphene and related materials are two-dimensional (2D) fully conjugated networks, similar covalent organic frameworks (COFs) could offer tailored electronic and magnetic properties. Jin et al. synthesized a fully π-conjugated COF through condensation reactions of tetrakis(4-formylphenyl)pyrene and 1,4-phenylen...

Covalent organic frameworks are designed to have backbones with different yet discrete contents of triarylamine units that inetract weakly with CO2. Adsorption experiments indicate that the triarylamine units dominate the CO2 adsorption process and the CO2 uptake increases monotonically with the triarylamine content. These profound collective effec...

Covalent organic frameworks (COFs) have emerged as a tailor-made platform for designing layered two-dimensional polymers. However, most of them are obtained as neutral porous materials. Here, we report the construction of ionic crystalline porous COFs with positively charged walls that enable the creation of well aligned yet spatially confined ioni...

Covalent organic frameworks (COFs) have emerged as a tailor-made platform for designing layered two-dimensional polymers. However, most of them are obtained as neutral porous materials. Here, we report the construction of ionic crystalline porous COFs with positively charged walls that enable the creation of well aligned yet spatially confined ioni...

The predesignable porous structures found in covalent organic frameworks (COFs) render them attractive as a molecular platform for addressing environmental issues such as removal of toxic heavy metal ions from water. However, a rational structural design of COFs in this aspect has not been explored. Here we report the rational design of stable COFs...

Organic porous polymer ( OPP) materials are a class of multi-dimensional porous network materials, which are built via the strong covalent bonds linkage of various organic building blocks with different geometries and topologies, and recently become a new rising research field in porous material sciences. OPPs can be generally divided into two cate...

Enormous research efforts are focusing on the design and synthesis of advanced luminescent systems, owing to their diverse capability in scientific studies and technological developments. In particular, fluorescence systems based on aggregation-induced emission (AIE) have emerged to show great potential for sensing, bio-imaging, and optoelectronic...

Covalent organic frameworks (COFs) are a class of crystalline porous polymer that allows the atomically precise integration of organic units into extended structures with periodic skeletons and ordered nanopores. One important feature of COFs is that they are designable; that is, the geometry and dimensions of the building blocks can be controlled...

Highly ordered discrete assemblies of chlorophylls that are found in natural light-harvesting antennae are key to photosynthesis, which converts light energy to chemical energy and is the principal producer of organic matter on Earth. Porphyrins and phthalocyanines, which are analogues of chlorophylls, exhibit a strong absorbance of visible and nea...

Dichtel and co-workers dramatically improve electrochemical performance of conductive polymers, as explained here by Jiang and co-workers.

Covalent organic frameworks (COFs) have attracted much interest due to their utility as functional materials. Unfortunately, experimental synthesis struggles with low single crystallinity of COFs. We have theoretically investigated isomer structures of a representative two-dimensional COF for both monolayer and three-dimensional stacking orders. We...

Covalent organic frameworks are a class of crystalline porous polymers that integrate molecular building blocks into periodic structures and are usually synthesized using two-component [1+1] condensation systems comprised of one knot and one linker. Here we report a general strategy based on multiple-component [1+2] and [1+3] condensation systems t...

Supplementary Figures 1-193, Supplementary Tables 1-18, Supplementary Note 1 and Supplementary References

Highly luminescent covalent organic frameworks (COFs) are rarely achieved because of the aggregation-caused quenching (ACQ) of π-π stacked layers. Here, we report a general strategy to design highly emissive COFs by introducing an aggregation-induced emission (AIE) mechanism. The integration of AIE-active units into the polygon vertices yields crys...

Progress over the past decades in proton-conducting materials has generated a variety of polyelectrolytes and microporous polymers. However, most studies are still based on a preconception that large pores eventually cause simply flow of proton carriers rather than efficient conduction of proton ions, which precludes the exploration of large-pore p...

Organic optoelectronics are promising technologies for energy conversion. However, the electrode interlayer, a key material between active layers and conducting electrodes that controls the transport of charge carriers in and out of devices, is still a chemical challenge. Herein, we report a class of porous organic polymers with tunable work functi...

Organic optoelectronics are promising technologies for energy conversion. However, the electrode interlayer, a key material between active layers and conducting electrodes that controls the transport of charge carriers in and out of devices, is still a chemical challenge. Herein, we report a class of porous organic polymers with tunable work functi...

We demonstrate the profound effects of spatially confined guest molecules in one-dimensional nanochannels on X-ray diffraction behaviors of covalent organic frameworks. Our results give insights into the abnormal X-ray diffraction patterns and suggest a novel molecular dynamic strategy for resolving crystalline structures.