Our journey in organophosphorus research over the past 26 years is compiled in this Personal Account. Advances in palladacycle design have engendered a shift in our focus from template‐mediated transformations to catalysis for the direct preparation of chiral phosphines containing a wide variety of functional groups. Novel approaches to access previously inaccessible phosphines and their applications in cancer research are summarized herein.
Rhodamine hydrazides and hydroxamates derived from hydrazines and hydroxylamines have been applied as fluorescent chemosensors. Reaction‐based irreversible probes based on the specific chemical reactions of reactive target species have been developed and applied in bio‐imaging studies. The strong chelation frames provided by the rhodamine hydrazides and hydroxamates have been utilized for the monitoring of metal ions, amino acids, and reactive acid derivatives. This Personal Account focuses on our perspective of developing fluorescent probes based on rhodamine hydrazides and hydroxamates.
This review seeks to provide coverage on the recent advances in chiral squaramide‐catalyzed asymmetric transformations and their applications in the synthesis of a variety of chiral biologically active compounds. It aims to give an overview highlighting the new reaction types and enantioenriched medicinal scaffolds developed in the last few years.
Electron‐deficient enamines such as enaminones and enaminoesters are moieties showing widespread application in organic synthesis. Among the various available electron‐deficient enamines, the N,N‐disubstituted amino‐functionalized ones (tertiary enamines) represent a class of special enamines with distinct properties and important applications. Based on our longstanding interest in exploring novel synthetic methods using electron‐deficient tertiary enamines, we present herein the research advances in organic synthesis via domino reactions making use of the combinatorial C–N, C=C, C–H, and other bond transformations of electron‐deficient tertiary enamines.
Asymmetric hydrogenation is one of the most efficient and atom‐economical tools to prepare chiral molecules. However, the enantiodiscrimination of simple, minimally functionalized olefins is still challenging and requires more sophisticated ligand design. Herein, we discuss our progress in the successful development of ligand design for the iridium‐catalyzed asymmetric hydrogenation of minimally functionalized olefins.
In contrast to the conventional group transfer polymerization (GTP) using a catalyst of either an anionic nucleophile or a transition‐metal compound, the organocatalyzed GTP has to a great extent improved the living characteristics of the polymerization from the viewpoints of synthesizing structurally well‐defined acrylic polymers and constructing defect‐free polymer architectures. In this article, we describe the organocatalyzed GTP from a relatively personal perspective to provide our colleagues with a perspicuous and systematic overview on its recent progress as well as a reply to the curiosity of how excellently the organocatalysts have performed in this field. The stated perspectives of this review mainly cover five aspects, in terms of the assessment of the livingness of the polymerization, limit and scope of applicable monomers, mechanistic studies, control of the polymer structure, and a new GTP methodology involving the use of tris(pentafluorophenyl)borane and hydrosilane.
A copper complex has proven to be a potent catalyst for forming a C–B bond via diborylation of arynes and alkynes, affording vic‐diborylarenes and vic‐diborylalkenes with high efficiency. A boryl‐substituted organocopper species, which is intermediately generated in the diborylation, has been found to be captured by a tin or a carbon electrophile, leading to three‐component borylstannylation or carboboration, in which C–B and C–Sn (or C) bonds are constructed simultaneously. Furthermore, reducing the Lewis acidity of the boron center with 1,8‐diaminonaphthalene decisively alters the regiochemical behavior of the borylcopper species, enabling the installation of a boryl moiety to occur at an internal carbon of terminal alkynes in borylstannylation and protoboration. Copper catalysis for C–Sn and C–Si bond‐forming processes via distannylation, hydrostannylation and silylstannylation, as well as silver catalysis for a C–B bond‐forming reaction, is also described.
This article describes recent developments in C3‐symmetric tris‐urea low‐molecular‐weight gelators and their applications. The C3‐symmetric tris‐ureas are excellent frameworks to form supramolecular polymers through noncovalent interactions. In organic solvents, hydrophobic tris‐ureas form supramolecular gels. Amphiphilic tris‐ureas form supramolecular gels in aqueous media. Functional supramolecular gels were prepared by introducing appropriate functional groups into the outer sphere of tris‐ureas. Supramolecular hydrogels obtained from amphiphilic tris‐ureas were used in the electrophoresis of proteins. These electrophoreses results showed several unique characteristics compared to typical electrophoreses results obtained using polyacrylamide matrices.
BODIPY laser dyes constitute a fascinating topic of research in modern photochemistry due to the large variety of options its chromophore offers, which is ready available for a multitude of synthetic routes. Indeed, in the literature one can find a huge battery of compounds based on the indacene core. The possibility of modulating the spectroscopic properties or inducing new photophysical processes by the substitution pattern of the BODIPY dyes has boosted the number of scientific and technological applications for these fluorophores. Along the following lines, I will overview the main results achieved in our laboratory with BODIPYs oriented to optoelectronic as well to biophotonic applications, stressing the more relevant photophysical issues to be considered in the design of a tailor‐made BODIPY for a certain application and pointing out some of the remaining challenges.
With their remarkable properties and wide‐ranging applications, nanostructures of noble metals and metal oxides have been receiving significantly increased attention in recent years. The desire to combine the properties of these two functional materials for specific applications has naturally prompted research in the design and synthesis of novel nanocomposites, consisting of both noble metal and metal‐oxide components. In this review, particular attention is given to core–shell type metal oxide‐coated noble metal nanostructures (i.e., metal@oxide), which display potential utility in applications, including photothermal therapy, catalytic conversions, photocatalysis, molecular sensing, and photovoltaics. Emerging research directions and areas are envisioned at the end to solicit more attention and work in this regard.
Artificial photosynthesis represents an attractive way of converting solar energy into storable chemical energy. The H2O oxidation half‐reaction, which is essential for producing the necessary reduction equivalents, is an energy‐demanding transformation associated with a high kinetic barrier. Herein we present a couple of efficient Ru‐based catalysts capable of mediating this four‐proton‐four‐electron oxidation. We have focused on the incorporation of negatively charged ligands, such as carboxylate, phenol, and imidazole, into the catalysts to decrease the redox potentials. This account describes our work in designing Ru catalysts based on this idea. The presence of the negatively charged ligands is crucial for stabilizing the metal centers, allowing for light‐driven H2O oxidation. Mechanistic details associated with the designed catalysts are also presented.
An effective exchange method is described whereby liposomal drug carriers of hydrophobic guest biomolecules are used to incorporate the guests into lipid membranes. The exchange method transfers the guest molecule from a cyclodextrin cavity to a liposome in water. Lipid‐membrane‐incorporated fullerenes (LMICx: x = 60 or 70) prepared by the exchange method have much higher liposomal stability and fullerene water solubility than those prepared by conventional methods. The LMIC60 have high photodynamic activities with respect to human cancer cells under 350–500 nm excitation. Furthermore, the LMIC60 bilayers, containing light‐harvesting antenna molecules in addition to the C60, showed improved activities at the optimal wavelength for photodynamic therapy.
Transition‐metal complex triplet photosensitizers are versatile compounds that have been widely used in photocatalysis, photovoltaics, photodynamic therapy (PDT) and triplet–triplet annihilation (TTA) upconversion. The principal photophysical processes in these applications are the intermolecular energy transfer or electron transfer. One of the major challenges facing these triplet photosensitizers is the short triplet‐state lifetime, which is detrimental to the above‐mentioned photophysical processes. In order to address this challenge, transition‐metal complexes showing long‐lived triplet excited states are highly desired. This review article summarizes the development of this fascinating area, including the molecular design rationales, the principal photophysical properties, and the applications of these complexes in PDT and TTA upconversion.
Supramolecular drug delivery systems (SDDSs), including various kinds of nanostructures that are assembled by reversible noncovalent interactions, have attracted considerable attention as ideal drug carriers owing to their fascinating ability to undergo dynamic switching of structure, morphology, and function in response to various external stimuli, which provides a flexible and robust platform for designing and developing functional and smart supramolecular nano‐drug carriers. Pillar[n]arenes represent a new generation of macrocyclic hosts, which have unique structures and excellent properties in host–guest chemistry. This account describes recent progress in our group to develop pillararene‐based stimuli‐responsive supramolecular nanostructures constructed by reversible host–guest interactions for controllable anticancer drug delivery. The potential applications of these supramolecular drug carriers in cancer treatment and the fundamental questions facing SDDSs are also discussed.
Chemical synthesis offers unique opportunities to prepare proteins with precise control of the atomic composition. Thanks to recent breakthroughs in synthetic methods, the preparation of large and complex proteins composed of 200–300 residues has now become possible. With these advances, a unique toolbox has been created to enable chemical biologists to investigate proteins that are difficult or even impossible to achieve otherwise, such as posttranslationally modified proteins and proteins composed of d ‐amino acids. In this review we describe the latest achievements in constructing protein conjugates of record sizes, such as those that are involved in the ubiquitin system.
This focus review summarizes our recent efforts on the synthetic applications of bithiophene dicarbanions generated from three bithiophene isomers: 2,2′‐, 3,3′‐, and 2,3′‐bithiophene. Based on these bithiophene dicarbanions, a series of dithienothiophenes ( DTT s) and cyclooctatetrathiophenes ( COTh s) were synthesized by intra‐ and intermolecular cyclizations, respectively. Moreover, recent applications of DTT and COTh in characteristic compounds such as dendrimers, thio[8]circulenes, double helicenes, and thienoacenes are summarized in this account. Besides the synthetic work, some photoelectric properties of the thiophene‐based oligomers including organic field‐effect transistors and organic photovoltaics are briefly reviewed.
Multisubstituted olefins are fundamental motifs in organic compounds. In this account, we describe the synthesis of organic molecules bearing an olefinic moiety by the transition‐metal‐catalyzed regio‐ and stereoselective addition of a variety of interelement compounds to alkynes. Regio‐ and stereoselective silaboration, diborylation, and chlorothiolation have been achieved by using the transition‐metal catalysts. The subsequent cross‐coupling reactions of the boron‐containing alkenes to install various aryl groups afforded the corresponding tri‐ and tetraarylated olefins. This account describes our research on the highly regio‐ and stereoselective synthesis of multifunctionalized olefins such as tetraarylethenes with four different aryl groups.
Acenes, a type of polycyclic aromatic hydrocarbon containing linearly fused benzene rings, have received much attention from organic chemists, physical chemists, and materials scientists, due to their intriguing properties and potential applications in organic electronics. Without doubt, acene chemistry has been one of the hottest topics among the π‐conjugated systems. However, poor stability of acenes is the prominent issue that limits their applications. In this personal account, we summarize different strategies developed in our group to construct and stabilize acenes and acene analogues. In addition, the unique properties and applications of some molecules will be discussed.
The catalytic enantioselective carbonyl addition reaction has long attracted the interest of chemists because of its synthetic importance. Although many highly enantioselective reactions have been developed, with few exceptions the reactions are carried out at relatively high catalyst loadings, making them less practical for scale‐up applications. In addition, organometallic reagents employed as carbon nucleophiles have been limited to those with relatively low reactivity, such as diorganozincs and arylboronic acids. In an effort to enhance the practicality, a highly active and enantioselective chiral titanium catalyst system was recently developed in our laboratory, enabling the enantioselective carbonyl addition reaction to aldehydes using various organometallic reagents (RM; M = MgX, Li, BY2, ZnX, AlMe2) at lower catalyst loadings (≤5 mol %).
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