Engineering Multifunctional Capsules through the Assembly of Metal–Phenolic Networks

Metal–organic coordination materials are of widespread interest because of the coupled benefits of inorganic and organic building blocks. These materials can be assembled into hollow capsules with a range of properties, which include selective permeability, enhanced mechanical/thermal stability, and stimuli‐responsiveness. Previous studies have primarily focused on the assembly aspects of metal‐coordination capsules; however, the engineering of metal‐specific functionality for capsule design has not been explored. A library of functional metal–phenolic network (MPN) capsules prepared from a phenolic ligand (tannic acid) and a range of metals is reported. The properties of the MPN capsules are determined by the coordinated metals, allowing for control over film thickness, disassembly characteristics, and fluorescence behavior. Furthermore, the functional properties of the MPN capsules were tailored for drug delivery, positron emission tomography (PET), magnetic resonance imaging (MRI), and catalysis. The ability to incorporate multiple metals into MPN capsules demonstrates that a diverse range of functional materials can be generated.     

Metal-phenolic networks modified polyurethane as periosteum for bone regeneration

Treatment of bone defects still poses a great challenge in orthopedic clinics, and the vital role of periosteum in such processes has attracted widespread attention. However, studies focusing on the oxidative stress micro-environment with an artificial periosteum at the site of defect have been scarce. The intrinsic anti-oxidative properties and therapeutic potential for bone defects of metal-phenolic networks(MPNs)have provided a potential solution to this. Herein, we have developed a protocate...     

Carbohydrate Recognition through Noncovalent Interactions: A Challenge for Biomimetic and Supramolecular Chemistry

Carbohydrates are not always as “sticky” as one might expect . Even in organic solvents they are difficult targets for the supramolecular chemist, due to their complex, three-dimensional structures. In their natural environment (water) they are especially elusive, presenting challenges which will occupy synthetic and theoretical chemists for some time to come. The complex of an octaamide supramolecular receptor with β-D -glucopyranose, which binds through apolar and polar contacts, is shown.     

壳聚糖棒材表面仿生拒水改性的研究

分析壳聚糖棒材在湿态环境下力学性能衰减速率过快的原因,通过对植物叶拒水机理的仿生,将壳聚糖表面进行复合式仿生疏水改性.先对壳聚糖棒材表面进行酰化改性,降低了棒材表面极性,使棒材表面形成一种微观凹凸的粗糙结构.然后在此粗糙结构上进行生物酯涂覆,以达到仿植物叶的拒水效果.结果表明,壳聚糖棒材表面经过乙酰化处理,表面变得粗糙.经接触角实验和吸水速率测试表明,壳聚糖棒材表面经酰化改性后,降低了材料表面的极性及亲水性.通过控制酰化反应时间,能有效地增大棒材的接触角,使得最外层的生物酯涂层紧密结合,经模拟体液浸泡实验,该材料3个月内完全拒水,达到了预期的目的.     

Cation-Controlled Assembly of Polyoxotungstate-Based Coordination Networks

The Preyssler polyoxoanion, [NaP₅W₃₀O₁₁₀]¹⁴⁻ ({P₅W₃₀}), is used as a platform for evaluating the role of nonbridging cations in the formation of transition-metal-bridged polyoxometalate (POM) coordination frameworks. Specifically, the assembly architecture of Co²⁺-bridged frameworks is shown to be dependent on the identity and amount of alkali or alkaline-earth cations present during crystallization. The inclusion of Li⁺, Na⁺, K⁺, Mg²⁺, or Ca²⁺ in the framework synthesis is used to selectively synthesize five different Co²⁺-bridged {P₅W₃₀} structures. The influence of the competition between K⁺ and Co²⁺ for binding to {P₅W₃₀} in dictating framework assembly is evaluated. The role of ion pairing on framework assembly structure and available void volume is discussed. Overall, these results provide insight into factors governing the ability to achieve controlled assembly of POM-based coordination networks.     

A Green and Wide-Scope Approach for Chiroptical Sensing of Organic Molecules through Biomimetic Recognition in Water

Optical chirality sensing has attracted a lot of interest due to its potential in high-throughput screening in chirality analysis. A molecular sensor is required to convert the chirality of analytes into optical signals. Although many molecular sensors have been reported, sensors with wide substrate scope remain to be developed. Herein, we report that the amide naphthotube-based chirality sensors have an unprecedented wide scope for chiroptical sensing of organic molecules. The substrates include, but are not limited to common organic products in asymmetric catalysis, chiral molecules with inert groups or remote functional groups from their chiral centers, natural products and their derivatives, and chiral drugs. The effective chirality sensing is based on biomimetic recognition in water and on effective chirality transfer through guest-induced formation of a chiral conformation of the sensors. Furthermore, the sensors can be used in real-time monitoring on reaction kinetics in water and in determining absolute configurations and ee values of the products in asymmetric catalysis.     

硫化镉钠米微粒在聚合物网络中的组装

硫化镉钠米微粒在聚合物网络中的组装黄金满，杨毅，杨柏，刘式墉，沈家骢（吉林大学分子光谱与分子结构重点实验室、集成光电子国家重点实验室，长春，１３００２３）关键词组装，纳米微粒，离子交换，透射电子显微镜，电子衍射由于纳米半导体微粒的物理和化学性质介于分...     

Surface Assembly and Molecular Electronics

The use of molecules as electronic devices is one of the focuses in the emerging field of nanotechnology. Two issues of relevance to this topic will be discussed in this lecture. In the first part, I will discuss the interfacial electronic structure and electron transport mechanism at molecular-metal junctions. Recent results from my laboratory revealed the role of chemical anchor in electron transport and the formation of molecular quantum wells at metal/organic interfaces. In the second part, I will present a general strategy to integrate molecular components into silicon technology. The application of this chemistry beyond molecular electronics will also be discussed.     

A Multiple‐Stimulus‐Responsive Biomimetic Assembly Based on a Polyisocyanopeptide and Conjugated Polymer

An assembly was fabricated and was revealed to be a multiple‐stimulus‐responsive biomimetic hybrid polymer architecture. It was constructed by the hydrophobic interactions between a conjugated polyfluorene that contained 2,1,3‐benzothiadiazole units (PFBT) and a tri(ethylene glycol)‐functionalized polyisocyanopeptide (3OEG‐PIC). The introduction of PFBT to the polyisocyanopeptide (PIC) network allowed for the incorporation of responsiveness to multiple stimuli including temperature, CO₂, carbonic anhydrase, and nonlinear mechanics, which mimics natural processes and interactions. Furthermore, the light‐harvesting and signal amplification characteristics of PFBT endowed the supramolecular assembly with the essential function of fluorescence monitoring for biological processes.     

Biomimetic synthesis of leukotriene A

A biogenetically patterned conversion of $\text{1}$ into $\text{2}$ is described. This transformation has been found to be non-stereospecific with respect to the geometry of the newly generated double bond at C9(10).     

A Novel Method for Biomimetic Synthesis of Mannich Bases

Since the early studies of Mannich, Mannich reaction has become an important tool for the synthesis of new compounds. Mannich bases can be either directly employed or used as intermediates. In this work, the one‐carbon unit transfer reaction of tetrahydrofolate coenzyme was initiated. 1,3‐Dimethylimidazolidine as a new tetrahydrofolate coenzyme model at formaldehyde oxidation level was used to react with ketone having active hydrogen atoms and amine to give the corresponding Mannich base in good yield by a covert Mannich reaction. A novel method for biomimetic synthesis of various Mannich bases is provided.     

Catalytic Enantioselective Synthesis of Mariline A and Related Isoindolinones through a Biomimetic Approach

The catalytic enantioselective synthesis of isoindolinones was achieved through the condensation of 2‐acyl‐benzaldehydes and anilines. In the presence of 1 mol % of a chiral phosphoric acid catalyst, reactions reach completion within 10 min and provide products with up to 98 % ee . Anilines with an ortho t ‐butyl group form atropisomeric products, thereby enabling the simultaneous generation of axial and point chirality from two achiral substrates. This method was applied to the first synthesis of mariline A.     

On-Surface Assembly of Hydrogen- and Halogen-Bonded Supramolecular Graphyne-Like Networks

Demonstrated here is a supramolecular approach to fabricate highly ordered monolayered hydrogen- and halogen-bonded graphyne-like two-dimensional (2D) materials from triethynyltriazine derivatives on Au(111) and Ag(111). The 2D networks are stabilized by N⋅⋅⋅H−C(sp) bonds and N⋅⋅⋅Br−C(sp) bonds to the triazine core. The structural properties and the binding energies of the supramolecular graphynes have been investigated by scanning tunneling microscopy in combination with density-functional theory calculations. It is revealed that the N⋅⋅⋅Br−C(sp) bonds lead to significantly stronger bonded networks compared to the hydrogen-bonded networks. A systematic analysis of the binding energies of triethynyltriazine and triethynylbenzene derivatives further demonstrates that the X₃-synthon, which is commonly observed for bromobenzene derivatives, is weaker than the X₆-synthon for our bromotriethynyl derivatives.     

On‐Surface Assembly of Hydrogen‐ and Halogen‐Bonded Supramolecular Graphyne‐Like Networks

Demonstrated here is a supramolecular approach to fabricate highly ordered monolayered hydrogen‐ and halogen‐bonded graphyne‐like two‐dimensional (2D) materials from triethynyltriazine derivatives on Au(111) and Ag(111). The 2D networks are stabilized by N???H?C(sp) bonds and N???Br?C(sp) bonds to the triazine core. The structural properties and the binding energies of the supramolecular graphynes have been investigated by scanning tunneling microscopy in combination with density‐functional theory calculations. It is revealed that the N???Br?C(sp) bonds lead to significantly stronger bonded networks compared to the hydrogen‐bonded networks. A systematic analysis of the binding energies of triethynyltriazine and triethynylbenzene derivatives further demonstrates that the X₃‐synthon, which is commonly observed for bromobenzene derivatives, is weaker than the X₆‐synthon for our bromotriethynyl derivatives.     

基于聚琥珀酰亚胺衍生物仿生超亲水表面的制备及性能

利用对聚琥珀酰亚胺(PSI)的亲核加成反应,仿生设计合成侧基带有多巴胺和磺酸甜菜碱两性离子基团的新型聚琥珀酰亚胺衍生物(PSI-DA-ZW);通过聚琥珀酰亚胺衍生物中多巴邻苯二酚基团的氧化自聚和沉积,制备了仿生超亲水功能涂层表面(PSI-DA-ZW/glass).利用X射线光电子能谱仪(XPS)、扫描电子显微镜(SEM...     

Directed Nanoparticle Assembly through Polymer Crystallization

Nanoparticles can be assembled into complex structures and architectures by using a variety of methods. In this review, we discuss recent progress of using polymer crystallization (particularly polymer single crystals, PSCs) to direct nanoparticle assembly. PSCs have been extensively studied since 1957. Mainly appearing as quasi-two-dimensional (2D) lamellae, PSCs are typically used as model systems to determine polymer crystalline structures, or as markers to investigate the crystallization process. Recent research has demonstrated that they can also be used as nanoscale functional materials. Herein, we show that nanoparticles can be directed to assemble into complex shapes by using in situ or ex situ polymer crystal growth. End-functionalized polymers can crystallize into 2D nanosheet PSCs, which are used to conjugate with complementary nanoparticles, leading to a nanosandwich structure. These nanosandwiches can find interesting applications for catalysis, surface-enhanced Raman spectroscopy, and nanomotors. Dissolution of the nanosandwich leads to the formation of Janus nanoparticles, providing a unique method for asymmetric nanoparticle synthesis.     

Design of Amphiphilic Peptide Geometry towards Biomimetic Self‐Assembly of Chiral Mesoporous Silica

In nature, diatoms and sponges are exquisite examples of well‐defined structures produced by silica biomineralisation, in which proteins play an important role. However, the artificial peptide templating route for the silica mesostructure remains a formidable and unsolved challenge. Herein, we report our effort on the design of amphiphilic peptides for synthesising a highly ordered two‐dimensional (2D)‐hexagonal and lamellar chiral silica mesostructure using trimethoxysilylpropyl‐N,N,N‐trimethylammonium chloride as the co‐structure directing agent (CSDA). The geometry of the peptide was designed by adding proline residues into the hydrophobic chain of the peptide to break the β‐sheet conformation by weakening the intermolecular hydrogen bonds; this led to the mesophase transformation from the most general lamellar structure to the 2D hexagonal P6mm mesostructure by increasing the amphiphilic molecules packing parameter g. Enantiomerically pure chiral mesostructures were formed thanks to the intrinsic chirality and relatively strong intermolecular hydrogen bonds of peptides.     

Polyphosphazene Microcapsules Fabricated through Covalent Assembly

Hollow polyphosphazene microcapsules have been fabricated by the covalent layer‐by‐layer assembly of polydichlorophosphazene (PDCP) and hexamethylenediamine (HDA) on aminosilanized silica particles, followed by core removal in a HF/NH₄F solution. The hollow and intact microcapsules in both wet and dry states have been characterized by transmission electron microscopy and confocal laser scanning microscopy. The chemical structure of the microcapsules has been verified by FT‐IR spectroscopy. The microcapsules could be hydrolytically degraded in a phosphate buffer at biological pH.

     

Reconstitution of Motor Proteins through Molecular Assembly

What is the most favorite and original chemistry developed in your research group?The most favorite and original chemistry developed in my research group is about the reconstitution of motor proteins in artificially designed and assembled units.It is based on the molecular assembly technique,but the method is different from the conventional approach.