Three-dimensional Crystalline Research Articles

Three-Dimensional Crystalline Organic Framework Stabilized by Molecular Mortise-and-Tenon Jointing.

Three-dimensional (3D) crystalline organic frameworks with complex topologies, high surface area, and low densities afford a variety of application prospects. However, the design and construction of these frameworks have been largely limited to systems containing polyhedron-shaped building blocks or those relying on component interpenetration. Here, we report the synthesis of a 3D crystalline organic framework based on molecular mortise-and-tenon jointing. This new material takes advantage of tetra(4-pyridylphenyl)ethylene and chlorinated bis(benzodioxaborole)benzene as building blocks and is driven by dative B-N bonds. A single-crystal X-ray diffraction analysis of the framework reveals the presence of two-dimensional (2D) layers with helical channels that are formed presumably during the boron-nitrogen coordination process. The protrusion of dichlorobenzene units from the upper and lower surfaces of the 2D layers facilitates the key mortise-and-tenon connections. These connections enable the interlocking of adjacent layers and the stabilization of an overall 3D framework. The resulting framework is endowed with high porosity and attractive mechanical properties, rendering it potentially suitable for the removal of impurities from acetylene.

Simultaneous integration of the photosensitizer hemin and biocatalyst nanoferrihydrite into a single protein nanocage for selectively photocatalytic CO2 reduction

The artificial photoreduction of CO2 into fuels with precious metal-based photosensitizers such as Ru, Re, and Ir represents a potential way to minimize global warming caused by the growing concentration of CO2, but these noble metal-based photosensitizers present unsustainable and negative environmental impact issues, thereby limiting their applications. Herein, bioinspired by the inherent ability of Escherichia coli ferritin (EcBFR) to bind to hemin, we constructed a photocatalytic-CO2-conversion platform by using a single shell-like EcBFR molecule where up to 12 of hemin molecules can be incorporated into its intersubunit interfaces as photosensitizers, while the semiconductor photocatalysts nanoferrihydrites are catalytically synthesized and encapsulated within the protein inner cavity. Consequently, the constructed platform can selectively, effectively reduce CO2 to formic acid with 1-benzyl-1,4-dihydronicotinamide (BNAH) as the electron donor in aqueous solution under mild conditions. To improve the recyclability of the above platform, we designed a three-dimensional (3D) protein crystalline framework with the above constructed hybrid molecules as building blocks through π-π interactions. Notably, such protein framework enables the recyclability to be improved up to at least 5 cycles as compared to the individual protein nanocage. All these findings pave the way for CO2 photoreduction by naturally occurring heme as the photosensitizer in an environmentally friendly manner.

A novel glass ionomer cement with silver zeolite for restorative dentistry

ObjectiveTo develop an antimicrobial silver zeolite glass ionomer cement (SZ-GIC) and determine its biocompatibility, physical, adhesive and antibacterial properties. MethodsSilver nitrate and sodium zeolite were used to synthesize silver zeolite (SZ). SZ-GICs were prepared by incorporating SZ into GIC at 5% (SZ-GIC5), 2% (SZ-GIC2), or 1% (SZ-GIC1) by weight, respectively. The SZ-GICs were characterized by evaluating surface morphology, topography and elemental composition. SZ-GICs’ biocompatibility was assessed by evaluating cell cytotoxicity. Their physical properties were determined by testing setting time, compressive strength, flexural strength, water sorption and solubility. Their adhesive property was assessed by evaluating micro-tensile bond strength. Their antibacterial properties were assessed by evaluating biofilm growth kinetic, metabolic activity, viability and morphology. GIC was used as a control. ResultsSZ was a three-dimensional crystalline mineral. SZ-GICs (including SZ-GIC 5, 2 and 1) showed similar surface morphology and topography to GIC. SZ-GIC1 and GIC had no difference in cell cytotoxicity (p>0.05). SZ-GICs and GIC showed no difference in setting time (p>0.05). SZ-GICs had higher compressive and flexural strength than GIC (p<0.05). SZ-GIC2 and SZ-GIC1 showed lower water sorption and solubility than GIC (p<0.05). SZ-GICs had higher micro-tensile bond strength than GIC (p<0.05). Biofilms on SZ-GICs’ surfaces showed lower colony-forming units, decreased metabolic activities, higher percentages of dead cells and more ruptured bacterial cells compared with those on GIC. ConclusionSZ-GIC with silver zeolite at 1% by weight are as biocompatible as conventional GIC. The SZ-GICs have enhanced physical, adhesive and antibacterial properties than GIC. Clinical significanceA silver zeolite glass ionomer cement was developed. The SZ-GICs have great potential for caries prevention and management.

Directed Compartmentalization of Mg2+ and Carbonic Anhydrase by Designed Three-Dimensional Protein Crystalline Frameworks for Efficient Conversion of CO2 into Nanoparticles

CO2 mineralization by colloidal nanoclusters of MgO or CaO represents one effective way to reduce its levels in the atmosphere. However, a high temperature (>200 °C) is required for this process. Herein, we found that the Mg2+-mediated Thermotoga maritima ferritin (TmFtn) nanocage has the ability to convert CO2 (3.128 mmol per gram of protein) into MgCO3 nanoparticles in an aqueous solution with Mg2+ as starting materials at room temperature, but the rate of such bioconversion is relatively slow. To improve the CO2 conversion efficiency, we constructed a two-compartment system based on three-dimensional (3D) protein crystalline frameworks by using dimeric TmFtn as building blocks, which consists of two types of compartments, namely, small ferritin cavity and large interglobular space. By using the system, directed compartmentalization of Mg2+ and carbonic anhydrase (CA) according to their difference in size can be realized using a one-pot method. Consequently, the CO2 conversion value of the CA-encapsulated protein crystalline frameworks reaches as high as around 8.485 mmol per gram of protein, while the conversion rate increases by 2 to 3 times. Notably, its reversible disassembly and reassembly property endows the frameworks with satisfied recyclability, allowing them to be suitable for practical applications.

Inhibition by Water during Heterogeneous Brønsted Acid Catalysis by Three-Dimensional Crystalline Organic Salts

A new self-assembled and self-healing class of metal free, recyclable, heterogeneous Bronsted acid catalysts has been developed by the protonation of aniline derivatives (tetrakis(4-aminophenyl)met...

Geometric Response and Disclination-Induced Skin Effects in Non-Hermitian Systems.

We study the geometric response of three-dimensional non-Hermitian crystalline systems with nontrivial point-gap topology. For systems with fourfold rotation symmetry, we show that in the presence of disclination lines with a total Frank angle, which is an integer multiple of 2π, there can be nontrivial one-dimensional point-gap topology along the direction of the disclination lines. This results in disclination-induced non-Hermitian skin effects. By doubling a non-Hermitian Hamiltonian to a Hermitian three-dimensional chiral topological insulator, we show that the disclination-induced skin modes are zero modes of the effective surface Dirac fermion(s) in the presence of a pseudomagnetic flux induced by disclinations. Furthermore, we find that our results have a field theoretic description, and the corresponding geometric response actions (e.g., the Euclidean Wen-Zee action) enrich the topological field theory of non-Hermitian systems.

In Situ Optical Characterization of Twinning in Liquid Crystalline Blue Phases.

Crystal twinning is an intergrowth of two or more single crystals of the same species with specific crystallographic relations in their orientations. Here, we perform microscopic optical characterization of (211) twins in the three-dimensional liquid crystalline phase known as the blue phase (BP), with I4132 space group symmetry. We describe the effect of twinning on the optical diffraction pattern-Kossel pattern-of blue phases and analyze the patterns to deduce structural information such as the twin elements and the previously unnoticed deviations from the perfect cubic structure at zero electric field. Further, we obtain in situ observations as a field is applied along the [110] direction of the twinning crystals and find that the twin boundary shows a pinning effect that defines the orientation of the twinned pair through the cubic-to-orthogonal structure transformation. Our findings not only provide important insights for the application of BPs as electro-optic crystals but also present a step in understanding the hierarchical structures that are crystallographic.

Three-dimensional supramolecular crystalline materials based on Keggin-based polyoxometalates and 1,2-Bis (4-pyridyl) ethylene for supercapacitor electrodes

To research the application of polyoxometalates (POMs)-based supramolecular crystalline materials in supercapacitors, two new compounds, H3PWVI12O40·(BPE)2.5·3H2O(1) and H3PMoVI12O40·(BPE)2.5·3H2O (2) (BPE = 1,2-Bis(4-pyridyl)ethylene) have been synthesized by a one-step hydrothermal method. Their structures are determined by single-crystal X-ray diffraction analysis and further characterized by FTIR spectroscopy, powder X-ray diffraction, and bond valence sum analysis. The POMs cluster ([H3PWVI12O40] or [H3PMoVI12O40]) acts as a connector to connect five BPE units through hydrogen bonds, generating a three-dimensional structure. The capacitance performance of these two compounds is tested by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. Compared with compound 1 and parent H3PMoVI12O40, compound 2 shows better electrochemical performances with a capacitance of 137.5 F g–1 at 2 A g–1. Compound 2 also has good cycle stability at a current density of 10 A g–1 and still has an initial capacitance of 92% after 1000 cycles. This work shows that hybrid supramolecular crystal materials based on polyoxometalates may provide an alternative way to improve the performance of POMs-based capacitor electrode materials. Two POMs-based supramolecular crystalline materials were synthesized by a hydrothermal method. The supercapacitor performance of these two compounds is better than their parents POMs(PW12 and PMo12). Among them, compound 2 displays specific capacitance (137.5 F g–1 at 2 A g–1) and better cycle stability (92.0% after 1000 cycles).

AIE-MOF materials for biological applications.

Metal-Organic Frameworks (MOFs), coming under the realm of coordination chemistry, are unparalleled and the most studied among the group of porous materials. Structurally, these are well-defined three-dimensional crystalline products that can be tuned for various potential applications with a range of physico-chemical properties. More recently, aggregation-induced emission (AIE) and AIE of MOF material has attracted tremendous attention due to promising applications in biology. However, a chapter summarizing the work in AIE-MOFs materials has never been reported till date. A comprehensive review on the AIE and MOFs separately is beyond the reach of this chapter. Hence, we have summarized overview of recent developments in the syntheses and biological applications such as cell imaging, heparin detection, and drug delivery. In the end, conclusion, prospects and challenges in the arena of AIE-MOF materials are also highlighted.

Novel One-Dimensional Covalent Organic Framework as a H+ Fluorescent Sensor in Acidic Aqueous Solution.

Covalent organic frameworks (COFs) represent an emerging class of two- or three-dimensional crystalline porous materials with delicate control over topology, composition, and porosity. Here, we develop a new COF made up of 1,3,6,8-tetrakis(p-formylphenyl)pyrene (TFPPy) and 4,4'-diaminobenzophenone (DABP) that exhibits a rare one-dimensional (1D) structure. The resulting frameworks possess good crystallinity, comparatively high Brunauer-Emmett-Teller (BET) surface area (426 m2/g), and good thermal stability (360 °C). Impressively, this 1D COF shows strong fluorescence and can be used as an excellent H+ sensor in an acidic aqueous solution.

Classification and carbon structural transformation from anthracite to natural coaly graphite by XRD, Raman spectroscopy, and HRTEM

Low-weight components of coal macromolecule were subjected to pyrolysis and condensation when magmatic rock intruded into coal measure, eventually, the residual condensed aromatic components can transform into microcrystalline graphite (coaly graphite). To study the structural transformation from anthracite to natural coaly graphite, ten samples with different graphitization degrees from Xinhua and Lutang of Hunan Province, China were characterized by organic geochemical analysis, X-ray diffraction (XRD), Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM).The geochemical parameters (proximate and ultimate analyses) and structural features (XRD, Raman, and HRTEM) of the series naturally graphitized coals exhibit a progressive change as the samples' locations closing to the intrusion. The series naturally graphitized coal samples were classified into four categories, including anthracite, meta-anthracite, semi-graphite, and coaly graphite. But, single parameter cannot classify the series metamorphosed coals well, multi parameters including ash free-basis volatile matter, petrographic features, and carbon structural parameters (based on XRD and Raman spectroscopy) should be considered, additionally, the lattice fringe change observed under HRTEM from anthracite to coaly graphite can verify for the classification. The relatively lower metamorphic grade samples (anthracite and meta-anthracite) have small crystalline sizes, prominent disorders, and amorphous carbon structure, whereas the crystallite structure of highest grade samples (coaly graphite) is three-dimensional crystalline order (testified by XRD and HRTEM), indicating a totally structural transformation from amorphous carbon of anthracite to highly ordered crystalline carbon of coaly graphite in the course of natural graphitization. The carbon structural evolution of coal under natural graphitization process will probably be helpful for synthetic graphite using coal to replace the expensive petroleum coke in the future.

Effective field theories for interacting boundaries of 3D topological crystalline insulators through bosonisation

Here, we analyse two Dirac fermion species in two spatial dimensions in the presence of general quartic contact interactions. By employing functional bosonisation techniques, we demonstrate that depending on the couplings of the fermion interactions the system can be effectively described by a rich variety of topologically massive gauge theories. Among these effective theories, we obtain an extended Chern–Simons theory with higher order derivatives as well as two coupled Chern–Simons theories. Our formalism allows for a general description of interacting fermions emerging, for example, at the gapped boundary of three-dimensional topological crystalline insulators.

Alice strings in non-Hermitian systems

Alice string is a topological defect with a very peculiar feature. When a defect with a monopole charge encircles an Alice string, the monopole charge changes sign. In this work, we generalize this notion to momentum space of periodic media with loss and gain. In particular, we find that the generic band-structure node for a three-dimensional non-Hermitian crystalline system acts as an Alice string, which can flip the Chern number charge carried by Weyl points and by exceptional-line rings. We discuss signatures of this topological structure for a lattice model with one tuning parameter, including non-trivial braiding of bulk band nodes, and the spectroscopic features of both the bulk and the surface states. We also explore how an Alice string affects the validity of the Nielsen-Ninomiya theorem, and present a mathematical description of the braiding phenomenon.

Engineering Functional DNA-Protein Conjugates for Biosensing, Biomedical, and Nanoassembly Applications.

DNA and protein are the most important two classes of biomacromolecules forming the basis of life. The conjugation of the two using crosslinking chemistries enables a combination of molecular recognition, enzymatic catalysis, and Watson-Crick hybridization properties. The DNA-protein conjugate with combined properties enables a broad range of applications, such as sensitive and selective bioassays, therapeutic agents, and building blocks for programmable nanoassemblies. In this review, we survey the conjugates from the aspects of conjugation chemistries as well as applications in biomedical and nanotechnology fields. We highlight the functions of both biological moieties of a conjugate for target binding and signal transduction in bioassays. We also review the use of DNA-protein conjugates for the construction of a variety of functional and dynamic nanostructures, from isolated hybrid cages to three-dimensional (3D) protein crystalline lattices. Moreover, these conjugates have been used as carriers to deliver enzymes or functional nucleic acids for disease treatments and gene editing.

Crystalline, porous, covalent polyoxometalate-organic frameworks for lithium-ion batteries

Abstract The development of covalent organic frameworks (COFs) with new building units is of critical importance for enriching the structural diversity and expanding their functions. However, the construction of COFs has been thus far limited primarily to traditional organic linkers. Herein, we report three-dimensional porous crystalline covalent polyoxometalate-organic frameworks (CPOFs) constructed from both inorganic and organic building blocks with reversible covalent bonds. These highly crystalline CPOFs exhibited 3-fold interpenetrated diamondoid topology, permanent porosity and high stability. Furthermore, these CPOFs could be directly applied as anode materials for lithium-ion batteries (LIBs) and displayed high reversible capacity (as high as 550 mA h g−1), rate performance, and cycling stability (up to 500 cycles).

Three-Dimensional Crystalline Modification of Graphene in all-sp2 Hexagonal Lattices with or without Topological Nodal Lines.

The discovery of fullerenes, nanotubes, and graphene has ignited tremendous interest in exploring additional all-sp2 carbon networks with novel properties. Here we identify by ab initio calculations a new series of three-dimensional crystalline modification of carbon in all-sp2 bonding networks that comprise trigonal polycyclic benzenoid nanoflakes in a 2 n2 ( n ≥ 4) atom hexagonal cell. The resulting 32-, 50-, 72-, and 98-atom structures (termed as tr32, tr50, tr72, and tr98) in trigonal ( P3̅ m1) symmetry are characterized as the crystalline modification of ( n × n × 1)-graphene in AA stacking, which are energetically more stable than or comparable to the solid fcc-C60 and (5,5) carbon nanotube. Electronic band structure calculations show that tr72 without 2 d (1/3, 2/3, z) symmetric carbon atoms is a semiconductor, while tr32, tr50, and tr98 with 2 d carbon atoms are topological nodal-line semimetals comprising nodal lines on the H-K-H' edge in the hexagonal Brillouin zone, as a three-dimensional extension of the Dirac point at the K-point in two-dimensional graphene. The present findings establish an additional crystalline modification of graphene in the all-sp2 carbon allotrope family and offer insights into its outstanding structural and electronic properties.

Balancing Noncovalent Interactions in the Self-Assembly of Nonplanar Aromatic Carboxylic Acid MOF Linkers at the Solution/Solid Interface: HOPG vs Au(111).

This study explores directed noncovalent bonding in the self-assembly of nonplanar aromatic carboxylic acids on gold and graphite surfaces. It is the first step in developing a new design strategy to create two-dimensional surface metal-organic frameworks (SURFMOFs). The acid molecules used are tetraphenylethene-based and are typically employed in the synthesis of three-dimensional (3D) MOF crystalline solids. They include tetraphenylethene tetracarboxylic acid, tetraphenylethene bisphenyl carboxylic acid, and tetraphenylethene tetrakis-phenyl carboxylic acid. The two-dimensional structures formed from these molecules on highly ordered pyrolytic graphite (HOPG) and Au(111) are studied by scanning tunneling microscopy in a solution environment. The process of monolayer formation and final surface linker structures are found to be strongly dependent on the combination of the molecule and substrate used and are discussed in terms of intermolecular and molecule-substrate interactions, bonding geometry, and symmetry of the acid molecules. In the case of linker self-assembly on HOPG, the molecule-substrate interactions play a significant role in the resulting surface structure. When the acid molecules are adsorbed on Au(111), the intermolecular interactions tend to dominate over the weaker molecule-substrate bonding. Additionally, the interplay of π-π interactions and hydrogen bonding that directs the surface self-assembly on different supports can be modified by varying the linker concentration. This is particularly applicable for the case of the acid molecules adsorbing on the Au(111) substrate. Precise control over predesigned surface structures and orientation of the nonplanar aromatic carboxylic linkers open up an exciting prospect for manipulating the direction of SURFMOF growth in two dimensions and potentially in 3D.

Facile synthesis and light-induced antibacterial activity of ketoprofen functionalized bacterial cellulose membranes

Bacterial cellulose (BC) has already attracted tremendous interests from researchers especially those working in the area of functional nanomaterials. In this work, the chemical grafting of BC with ketoprofen (KP) was performed through eco-friendly and simple SolReact method. Surface functionalization of BC was confirmed by FTIR, XRD, XPS, TG, SEM, and TEM. Meanwhile, the stress-strain and water contact angle were also measured simultaneously. The results showed that surface functionalization was achieved under the mild reaction condition. The three-dimensional (3D) microstructure and crystalline structure of BC were maintained without being destroyed. The thermal stability of BC-KP was improved while retaining hydrophilic property and mechanical property. The photochemical property of BC-KP showed that the ROS generation was positively correlated with the time of light irradiation. The results of antibacterial tests on E.coli and S.aureus showed that the BC-KP possessed best antibacterial performance after 30 min UVA light irradiation, reaching to 72.7% and 81.6%, respectively. SEM studies displayed the cell morphology changed and membrane damaged resulting from the ROS produced under the light irradiation, which was a potential approach to prevent the bacteria resistance to conventional antibiotics. The antibacterial BC-based membranes grafting with photodynamic antimicrobial agents may be utilized as an efficient healthcare product for prevention of infectious disease.

Research advances in covalent organic framework materials for sample pretreatment

Covalent organic frameworks (COFs) are two-dimensional or three-dimensional crystalline porous structures formed by the covalent bonding of organic monomers. As an emerging crystalline porous material, COFs have been widely used in various fields such as gas storage, catalysis, sensing, and drug delivery. In recent years, COFs have shown immense potential in analytical chemistry because of their low density, large surface area, and controllable structure. This paper reviews the application of porous COFs and their composites in sample pretreatment, including dispersive solid-phase extraction, solid phase micro-extraction, and magnetic solid phase extraction.

Tetrads in Solids: from Elasticity Theory to Topological Quantum Hall Systems and Weyl Fermions

Theory of elasticity in topological insulators has many common features with relativistic quantum fields interacting with gravitational field in the tetrad form. Here we discuss several issues in the effective topological (pseudo)electromagnetic response in three-dimensional weak crystalline topological insulators with no time-reversal symmetry that feature elasticity tetrads, including a mixed "axial-gravitational" anomaly. This response has some resemblance to "quasitopological" terms proposed for massless Weyl quasiparticles with separate, emergent fermion tetrads. As an example, we discuss the chiral/axial anomaly in superfluid 3He-A. We demonstrate the principal difference between the elasticity tetrads and the Weyl fermion tetrads in the construction of the topological terms in the action. In particular, the topological action expressed in terms of the elasticity tetrads, cannot be expressed in terms of the Weyl fermion tetrads since in this case the gauge invariance is lost.