Photochromic materials exhibit light-induced color change essentially due to the reversible structure change such as ring-open to ring-closed states upon photoirradiation, resulting in the distinct difference in photo-induced chemical reactions/physical properties. These photochromic properties have attracted much attention on the applications of ophthalmic lenses, photo-switches, molecular actuators, logic gates, and information storages. Among various photochromic systems, organic diarylethenes have become increasing interest because of their high thermal stability. Particularly, the ethene bridge with perfluorocyclopentene can bring excellent fatigue resistance and bistability to the diarylethene family, thereby nowadays it is adopted for developing diarylethene derivatives. The ethene bridges have very great effects on photochromic properties since they are located exactly in the photoreaction center. Given the difficulty in structurally modifying the classic ethene bridge of perfluorocyclopentene owing to its chemical inertness, several other ethene bridges have emerged to achieve higher performance and more applications. This review covers the latest research progresses on the important ethene bridges and their corresponding diarylethene derivatives, and their application prospects.

Contents
1 Introduction
2 Five-membered-ring bridges
2.1 Cyclopentene derivative bridges
2.2 Thiophene derivative bridges
2.3 Thiazole derivative bridges
2.4 Imidazole derivative bridges
2.5 Other five-membered-ring bridges
3 Six-membered-ring bridges
3.1 Non-aromatic bridges
3.2 Aromatic bridges
4 Miscellaneous bridges
5 Conclusion and outlook

Poly- and perfluoroalkyl substances (PFASs) are a family of anthropogenic chemicals widely used in the commercial and industrial applications due to their unique properties of stability, hydrophobicity and lipophobicity. Traditionally, PFASs are produced via two major manufacturing processes: electrochemical fluorination (ECF) and telomerization. Due to their persistence, toxicity and bioaccumulation, ECF-associated chemicals perfluorooctane sulfonic acid (PFOS), its salts and perfluorooctane sulfonyl fluoride (POSF) are placed into the Annex B of the Stockholm Convention (SC) on Persistent Organic Pollutants (POPs) in 2009. The ECF production has also been phased out gradually in the developed countries. However, the production of fluorotelomer alcohols (FTOHs) by telomerization has increased significantly. Recent studies have demonstrated that the biotransformation and abiotic transformation of FTOHs yielded perfluocarboxylic acids (PFCAs), which may be router for the ubiquitous distribution of PFCAs. Besides, some of the FTOHs intermediate metabolites have been demonstrated to be able to covalently bind with various biomolecules and thereby cause serious toxicity, while the final metabolites are showed to cause hepatotoxicity and renal toxicity. Recently, the environmental problems related to FTOHs have become the hotspots in environmental science, toxicology and epidemiology. This paper reviews the research progress on the production status, environmental occurrence, and the toxicities of FTOHs and the related metabolites. Finally, the currently existing problems and trends are discussed.

Contents
1 Introduction
2 Production status and human exposure of FTOHs
2.1 Production status
2.2 Human exposure of PFAAs
3 Environmental occurrence of FTOHs
3.1 Basic properties
3.2 Analytical methods
3.3 Environmental occurrence
4 Toxicological studies
4.1 Biotransformation of FTOHs
4.2 Toxicities of FTOHs and the related metabolites
5 Conclusion and outlook

Covalent organic frameworks (COF) arise as the new frontier among the enormous research efforts in functional materials. Due to their well-defined channel structure, tunable porosity, larger surface area, vast synthetic diversity and facile functionalization at the molecular level, COF has emerged as a matrix for heterogeneous catalysts. Such catalysts are generally constructed via the "bottom-up" strategies from building blocks. Utilizing a simple post- modification strategy, COF catalysts are prepared by loading metal particles or ions into the pores or interfaces. Benefiting from its structural superiority, COF catalysts with excellent catalytic activity will also make a great achievement. Here, this review focuses on recent advances of COF-functional catalysts, by briefly summarizing their synthetic strategies, targeted functionalization, and their perspectives in heterogeneous catalysis.

Contents
1 Introduction
2 Pd catalytic coupling reaction
2.1 Suzuki reaction
2.2 Sonogashira reaction
2.3 Heck reaction
3 Knoevenagel condensation
4 Redox reaction
5 Diels-Alder reaction
6 Michael addition
7 Solid acid catalysis reaction
8 Photocatalytic hydrogen production
9 Conclusion and outlook

Metal organic frameworks (MOFs) are very popular materials and have been largely researched in recent years. They have extremely wide ranges of applications in catalysis because of their variety of excellent properties. However, the research of MOFs themselves as catalysts is limited, the regularly porous structure and large surface area of MOFs can provide a natural physical space for loading highly dispersed metal nanocatalyst, which prevents the aggregation and leaching of metal nanoparticals. This has also been the major research direction of MOF catalysts in the last few years. This review reports the preparation methods of loading metal nanoparticles on MOFs to form bi- and multi-metallic catalysts and their applications in catalysis. The preparation methods,such as one pot synthesis, adsorption-reduction method, metal organic chemical vapor deposition method and solid grinding method are highlighted, and their applications in oxidation (the oxidation of alcohols, alkanes, alkenes and CO), hydrogenation (the hydrogenation of carbonyl compounds and olefinic compounds), Knoevenagel condensation and photocatalytic reaction (photocatalytic degradation of organic compounds and light-driven water splitting to produce hydrogen) are discussed in detail. In addition,the existing problems and the development prospects of such bi- and multi-metallic catalysts are also addressed in this review.

Contents
1 Introduction
2 The preparation methods of bi- or multi-metallic catalyst
2.1 One pot synthesis
2.2 Adsorption-reduction method
2.3 Metal organic chemical vapor deposition
2.4 Solid Grinding
2.5 Other methods
3 The applications of bimetallic or multi-metal catalyst
3.1 Oxidation reaction
3.2 Hydrogenation reaction
3.3 Knoevenagel condensation
3.4 Photocatalytic reaction
4 Conclusion and outlook

Tumor is one of the serious diseases which greatly threaten human's health. Therefore, the large amount of innovative anticancer drugs have been discovered and created. Among these anticancer drugs, cis-platinum and its analogs are some of the most effective chemotherapeutic agents in clinical use, particularly in the treatment of testicular and ovarian cancers. Unfortunately, they have several major drawbacks, such as cumulative toxicities of nephrotoxicity and ototoxicity, inherent or treatment-induced resistance. This has provided the urgency and motivation for developing novel platinum complexes with high antitumor effect and low toxic side effect on normal cells. This review highlights some methods on the development of the novel platinum complexes:(1) developing the platinum complex with new structure, like trans-platinum complex, multinuclear platinum complex, Pt(Ⅳ) complex; (2) developing new anticancer target, such as G-quadruplex (G4) DNA. By consideration of the anticancer mechanism of the drugs and the tolerance of cis-platinum, the prospect provides new ways to develop novel platinum complexes with high antitumor effect and low toxic side effect on normal cells. This review highlights recent progress of the platinum complexes as anticancer drugs and discuss their future potential in the medical fields.

Contents
1 Introduction
2 Nucleic acid
2.1 Duplex DNA
2.2 G-quadruplex DNA
3 Platinum complexes targeting duplex DNA
3.1 Classical platinum(Ⅱ) complexes
3.2 Trans-platinum(Ⅱ) complexes
3.3 Multi-nuclear platinum(Ⅱ) complexes
3.4 Platinum(Ⅳ) complexes
4 Platinum complexes targeting G-quadruplex DNA
4.1 Mono-nuclear platinum(Ⅱ) complexes
4.2 Multi-nuclear platinum(Ⅱ) complexes
5 Conclusion and outlook

The design and synthesis of new macrocyclic compounds always represent one of hot research fields in supramolecular chemistry. The development of classical macrocyclic compounds, such as crown ether, cyclodextrin, calixarene, cucurbituril and pillararene, enriches the contents of supramolecular chemistry. Meanwhile, the functionalizated macrocyclic compounds have been successfully used to create a number of applications including chemical sensors, molecular machines, biomimetic systems, supramolecular catalysts, stimuli-responsive systems, functional materials and drug delivery. Cucurbit uril bearing a rigid and hydrophobic cavity has gained great attention for its unique recognition property in water. Compared to that of other macrocyclic compounds, however, the functionalization of cucurbit uril is more difficult due to their chemical inertness. In the past few years, numerous efforts have been devoted to functionalize cucurbit uril and develop their host-guest recognition property not only in supramolecular chemistry, but also bio-chemistry, material chemistry, and medicinal chemistry. This review mainly focuses on summarizing the research progress of functionalized cucurbit uril, and comments on the bright future of their synthetic methods briefly.

Contents
1 Introduction
2 Condensation of substituted glycoluril with formaldehyde
3 Condensation of substituted glycoluril biether with glycolril
4 Condensation of substituted glycoluril biether with glycoluril oligomers
5 Oxidation of cucurbit[n]uril
6 Condensation of glycoluril oligomers with substituted aldehydes
7 Conclusion

Stimuli-responsive polymer has attracted much attention in recent years. This kind of polymer can respond to external stimuli and switch their properties. Gold nanoparticles have excellent catalytic properties which means a bright application prospect. However, gold nanoparticles are easy to aggregate in the application, and it will result in a remarkable decrease of catalytic property. So different carriers are usually required to immobilize gold nanoparticles. The introduction of the stimuli-responsive polymer into the catalyst systems of gold nanoparticles is a way to prevent the aggregation similar to other normal carriers, and at the same time a fascinating approach to controllable catalyst. This paper reviews recent research progress on this kind of catalyst systems, followed by the discussion of their fabrication, sensitivity and applications. Moreover, the development potential of this field is also discussed.

Contents
1 Introduction
2 Fabrication of stimuli-responsive polymer & gold nanoparticles catalyst systems
2.1 Au-S bond
2.2 Supramolecular system
2.3 In-situ reduction
2.4 Indirect methods
3 Sensitivity and applications of stimuli-responsive polymer & gold nanoparticles catalyst systems
3.1 Thermoresponsive catalyst system
3.2 pH-responsive catalyst system
3.3 CO₂-responsive catalyst system
3.4 Glucose-responsive catalyst system
4 Conclusion

As one kind of "click chemistry", thiol-epoxy reaction has drawn intensive attention in recent years due to its outstanding advantages, such as fast reaction rate, high selectivity, and mild reaction conditions. This review illustrates the base-catalyzed mechanism of thiol-epoxy reaction in details. The influences of base catalysts, substituent groups and solvents on the thiol-epoxy reaction rate are summarized. The inorganic base such as lithium hydrate and organic base such as tetrabutylammonium fluoride are excellent catalytic activity. The advantages and disadvantages of inorganic and organic base catalysts are compared as well. Thiols with electron-donating groups and epoxy with electron-withdrawing groups are more active, which are also influenced by steric effect. The reactions in bulk system usually have higher yield than the reactions in solution. Moreover, the applications of thiol-epoxy reaction in macromolecular materials are also demonstrated and classified into two types according to their different focuses: one is synthesis of structure-controllable macromolecules in the solvents, including the synthesis of macromolecules with linear or complicated structures and the modifications of macromolecules or surfaces; and the other one is preparation of crosslinking polymeric networks with excellent properties and practical potential in the bulk condition. Furthermore, the trends of thiol-epoxy reaction are prospected in brief.

Contents
1 Introduction
2 Mechanism of thiol-epoxy reaction
2.1 Base-catalyzed mechanism
2.2 Influence of base catalysts
2.3 Influence of substituent groups
2.4 Influence of solvent
3 Application of thiol-epoxy reaction in polymer science
3.1 Polymer with special structures in solvent
3.2 Crosslinking networks with high performances in bulk condition
4 Conclusion

Within large-volume polyolefin materials, the value-adding polyolefins have been commonly produced through the copolymerization of ethylene with α-olefin. The Ⅳ B metal complexes have provided various models of precatalysts toward α-olefin polymerization and copolymerization. Meanwhile those metal complexes have also been used as the intermediates or active species in order to understand the mechanism of olefin copolymerization. Targeting a practicing catalytic system for polyolefin industry, the Ⅳ B metal complexes would meet the demands of highly active catalysis, moreover, the catalytic systems should be remained enough stable at the elevated temperature. To have value-adding materials for higher profits, the catalytic system could be adaptable for polyolefins with various properties through being operated under different parameters; such features have been fitted well to Ⅳ B metal precatalysts, which achieve to produce polyolefins with the molecular weights in the useful range from medium to ultrahigh due to different polymerization conditions as well as functionalized polyolefins through the copolymerization of ethylene with α-olefin containing functional groups. Recent progress of Ⅳ B metal complexes for olefin polymerization and copolymerization has been reviewed herein, focusing on different metal complexes being classified due to groups of their ligands used. Moreover, the correlation between structures of metal complexes and their catalytic activity have been considered along with reaction temperatures.

Contents
1 Introduction
2 Constrained geometry catalysts
3 Imino-amido type catalysts
3.1 Pyridyl-amide catalysts
3.2 Imino-amido catalysts
3.3 Imino-enamido catalysts
3.4 Amidoquinoline catalysts
4 Bridging nitrogenous heterocyclic catalysts
5 Conclusion

The introduction of inorganic nanoparticles can make the polymer materials many characteristics, such as antibacterial, conductive, anti-ultraviolet. However, the inorganic nanoparticles are easy to agglomerate and less content of nanoparticles is introduced in polymer, so it is difficult to demonstrate advantage of nano material. Based on its unique droplet nucleation mechanism, miniemulsion polymerization can improve the inorganic nanoparticles’ dispersity and amount of introduction in polymer matrix, and control the morphology of the composites easily. It is an effective method to obtain the special morphology of organic/inorganic nanocomposites. This paper introduces the preparation process of organic/inorganic nanocomposite miniemulsion, and reviews the recent progress of different inorganic nanoparticles with organic matrix composites, such as nano-SiO₂, nano-ZnO, metal nanoparticles, nano-graphene oxide, etc. At last, some suggestions on the present development situation are given.

Contents
1 Introduction
2 Preparation and polymerization of organic/inorganic composite miniemulsion
3 The composite of different inorganic nanoparticles and organic matrix
3.1 The composite of nano-SiO₂ with organic matrix
3.2 The composite of nano-ZnO with organic matrix
3.3 The composite of metal nanoparticles with organic matrix
3.4 The composite of GO with organic matrix
3.5 The composite of other inorganic nanoparticles with organic matrix
4 Conclusion

The traditional peptide drugs are unstable in vivo conditions due to hydrolysis. The β-peptide that composed of β-amino acids has improved pharmacokinetic parameters than α-peptide and is valuable in drug development. The conformation restricted β-amino acids can form the β-peptidomimetics in order to improve its biological activity and metabolic stability. The restricted β-peptidomimetics can form fixed secondary structure and fold with specific way, then it has an ideal three-dimensional structure and embed in specific enzymes or receptors eventually. This review describes the methods of conformational restriction and the changes of biological activity or physical and chemical parameters after conformational restriction for β-peptidomimetics. Two kinds of conformationally restricted β-peptidomimetics including the local conformational restriction and the overall cyclization of β-peptidomimetics are reviewed. This paper could provide guidance for the rational design of β-peptide drugs.

Contents
1 Introduction
2 Local conformational restriction of β-peptides
2.1 Monoalkylating β² or β³-amino acids
2.2 Dialkylating β^2,3-amino acids
2.3 C^α-fluorinated β-amino acids
2.4 N-substituted β-amino acids
2.5 Ring substituted β-amino acids
3 The overall cyclization of β-peptides
3.1 Cyclization between the head and tail
3.2 Cyclization between the side chains
4 Research methods of the conformational restriction
4.1 Circular dichroism spectroscopy
4.2 Infrared spectroscopy
4.3 X-ray diffraction analysis
4.4 Nuclear magnetic resonance
4.5 Theoretical calculations
5 Conclusion

IL-6 is a widespread cytokine which participates in many biological responses. All members of the IL-6 cytokine family are able to activate STAT3, and STAT3 is also recognized as the main mediator of IL-6 functions. IL-6 binding to cell surface receptors results in the activation of the Janus kinases(JAKs) which cause STAT3 phosphorylated. Then activated STAT3 dimerizes translocates to the nucleus and combines with target genes with specific sites, then activats DNA transcriptional activity. Studies show that the abnormally activated STAT3 in cells plays an important role in tumorigenesis and malignant transformation. Meanwhile, STAT3 is a valid target for novel anticancer drug design. So far, many methods, such as structure-based virtual screening, high throughput screening, fragment-based drug design, have been used to screen and design novel STAT3 inhibitors, and thus several classes of small molecule compounds have been identified as STAT3 inhibitors. In this review, we mainly focus on the small molecule IL-6/STAT3 inhibitors especially target STAT3 protein which have been optimized and identified since 2013.

Contents
1 Introduction
2 Small molecule inhibitors of IL-6/STAT3 signaling pathway
2.1 1,4-Naphthoquinones
2.2 Quinolines
2.3 Derivatives of benzo[b]thiophene-1,1-dioxide
2.4 Derivatives of Niclosamide
2.5 Derivatives of salicylic acid
2.6 6-Aminobenzo[d]thiazole-2-thiols
2.7 Tetrahydropyridinepyrazoles
2.8 Flavonoids
2.9 Coumarins
2.10 Metal-containing compounds
2.11 Other small molecule IL-6/STAT3 inhibitors
3 Conclusion

As one of advanced oxidation processes(AOPs), catalytic ozonation has recently gained significant attention in the field of wastewater treatment. Heterogeneous catalytic ozonation have notable advantages of strong oxidation, less ozone dosage and especially its potentially greater effectiveness in the mineralization of organic matter. New catalysts have been studied world widely, but the reaction process and mechanisms are much more complicated. The efficiency of catalytic ozonation process depends to a great extent on the catalyst and its surface properties. On the surface active sites of catalyst,pollutants adsorbed form surface complexes or ozone decomposes to various reactive oxygen species such as surface atomic oxygen (^*O), surface peroxide (O₂^·-), hydroxyl radical (·OH). Thus the main mechanisms of heterogeneous catalytic ozonation are reviewed, including radical mechanism, oxygen vacancies theory, surface atomic oxygen mechanism, surface complexes theory and direct ozonation mechanism. The hydroxyl groups on the surface of catalyst are mainly catalytic active centers. The catalytic reaction mechanisms by hydroxyl groups are introduced in this paper. Surface properties of the catalysts determine the properties of the surface active sites and its amount, which play a key role in ozone decomposition. The structure and morphology, the specially surface area, the catalytic performance as well as reaction mechanisms of modified catalysts are reviewed. The future development of heterogeneous catalysts are also discussed to provide a theoretical reference of heterogeneous catalytic ozonation.

Contents
1 Introduction
2 Mechanism of heterogeneous catalytic ozonation
2.1 Radical mechanism
2.2 Oxygen vacancies mechanism
2.3 Surface atomic oxygen mechanism
2.4 Surface complexes mechanism
2.5 Direct ozonation mechanism
3 Catalytic reaction mechanisms by hydroxyl groups on the surface of catalyst
4 Heterogeneous catalytic ozonation mechanism after modification of the catalysts
4.1 Catalytic performance of modified catalysts
4.2 Reaction mechanism of modified catalysts
5 Conclusion and outlook