Wenqi Liu

University of South Florida | USF · Department of Chemistry

Developing an eco-friendly, efficient, and highly selective gold-recovery technology is urgently needed in order to maintain sustainable environments and improve the utilization of resources. Here we report an additive-induced gold recovery paradigm based on precisely controlling the reciprocal transformation and instantaneous assembly of the secon...

Motion-induced change in emission (MICE) is a phenomenon that can be employed to develop various types of probes, including temperature and viscosity sensors. Although MICE, arising from the conformational motion in particular compounds, has been studied extensively, this phenomenon has not been investigated in depth in mechanically interlocked mol...

Triplet excited-state organic chromophores present countless opportunities for applications in photocatalysis. Here we describe an approach to the engineering of the triplet excited states of aromatic chromophores, which involves incorporating pyrene into pyridinium-containing mechanically interlocked molecules (MIMs). The π-extended nature of the...

Significance During the past decades, the development of efficient methodologies for the creation of mechanically interlocked molecules (MIMs), such as catenanes and rotaxanes, has not only laid the foundation for the design and syntheses of artificial molecular machines (AMMs) but also opened up new research opportunities in multiple disciplines,...

Nanographenes have kindled considerable interest in the fields 11 of materials science and supramolecular chemistry as a result of their 12 unique self-assembling and optoelectronic properties. Encapsulating the 13 contorted nanographenes inside artificial receptors, however, remains 14 challenging. Herein, we report the design and synthesis of a t...

Since anions are vital for many chemical, biological and environmental processes, their recognition and separation continue to attract attention from chemists, materials scientists and engineers. Employing exo‐binding of artificial macrocycles to recognize selectively anions remains a challenge in supramolecular chemistry. Herein, we report the ins...

A instantaneous co-crystallization protocol relying on the selective recognition of the [PtCl6]²⁻ dianions by the exo-binding of cucurbit[6]uril has been demonstrated. This protocol could be exploited to recover platinum from spent vehicular three-way catalytic converters and other platinum-bearing metal scrap in a fast, efficient, and highly selec...

Stimuli‐responsive chromic materials such as photochromes, hydrochromes, thermochromes, and electrochromes have a long history of capturing the attention of scientists due to their potential industrial applications and novelty in popular culture. However, hybrid chromic materials that combine two or more stimuli‐triggered color changing properties...

The expression of biological functions, such as enzyme catalysis, immune response, and cargo transport in confined nanospaces, with very different physical and chemical environments from those in bulk solution, is of crucial importance to living systems. The construction of artificial nanoconfined containers, employing molecular engineering, has be...

We report the molecular recognition of the Au(CN)2– anion, a crucial intermediate in today’s gold mining industry, by α-cyclodextrin. Three X-ray single-crystal superstructures—KAu(CN)2⊂α-cyclodextrin, KAu(CN)2⊂(α-cyclodextrin)2, and KAg(CN)2⊂(α-cyclodextrin)2—demonstrate that the binding cavity of α-cyclodextrin is a good fit for metal-coordinatio...

The solid-state properties of organic radicals depend on radical–radical interactions that are influenced by the superstructure of the crystalline phase. Here, we report the synthesis and characterization of a substituted tetracationic cyclophane, cyclobis(paraquat-p-1,4-dimethoxyphenylene), which associates in its bisradical dicationic redox state...

Mechanically interlocked molecules (MIMs), which undergo controllable motions between their component parts in more than one dimension, are of interest in controlling nanoconfinement in a three-dimensional space. Cyclic [n]daisy chains ([cn]DCs) are a class of garland-like rotaxanes composed of self-complementary monomers with cross-threaded archit...

One ring threaded by two other rings to form a non-intertwined ternary ring-in-rings motif is a challenging task in noncovalent synthesis. Constructing multicolor photoluminescence systems with tunable properties is also a fundamental research goal, which can lead to applications in multidimensional biological imaging, visual displays, and encrypti...

A new supramolecular paradigm is presented for reliable capture and co‐precipitation of haloauric acids (HAuX 4 ) from organic solvents or water. Two classes of acyclic organic compounds act as complementary receptors (tectons) by forming two sets of directional non‐covalent interactions, (a) hydrogen bonding between amide (or amidinium) NH residue...

Ten rings on one axle Rotaxanes consist of molecular rings threaded on a central axle. Most approaches to their synthesis have focused on introducing a single ring per axle. Qiu et al. now report a systematic approach to threading up to 10 adjacent rings consecutively. The axle's end groups were constructed to attract free-floating rings when reduc...

Suitanes are two-component mechanically interlocked molecules in which one (torso) of the components, with several protruding limbs, is encompassed by another (suit) all-in-one component. This kind of molecular ship-in-a-bottle architecture remains a challenging one to make. Herein, we report a porphyrin-based suit[4]ane, which is composed of a por...

We report the encapsulation of free-base and zinc porphyrins by a tricyclic cyclophane receptor with subnanomolar binding affinities in water. The high affinities are sustained by the hydrophobic effect and multiple [CH···π] interactions covering large [π···π] stacking surfaces between the substrate porphyrins and the receptor. We discovered two co...

The rational design of wholly synthetic receptors that bind active substrates with ultrahigh affinities is a challenging goal, especially in water. Here, we report the synthesis of a tricyclic octacationic cyclophane, which exhibits complementary stereoelectronic binding towards a widely used fluorescent dye, perylene diimide, with picomolar affini...

A neutral tetralactam macrocycle was prepared in a few minutes in one pot and at high concentration using commercially available starting materials. NMR titration studies in DMSO revealed an anion affinity order of F- > AcO- > Cl- > Br-. Receptor affinity for F- is very high due in part to formation of a self-complementary dimer comprised of two “s...

Croconaines are an emerging class of near‐infrared dyes that are useful for various sensing, photothermal, optoelectronic, and photoacoustic applications. Previous work encapsulated a dumbbell‐shaped croconaine dye whose structure contains two thiophene flanking units inside a tetralactam macrocycle and produced a croconaine rotaxane 1 with a narro...

A new family of fluorescent thiophene and thienothiophene-containing squaraine dyes is described with tunable wavelengths that cover the absorption/emission range of 600–800 nm. The deep-red and near-infrared fluorescent compounds were easily prepared by simple synthesis and purification methods. Spectral studies showed that each squaraine was rapi...

Fluorescent molecular probes were prepared by a programmed non‐covalent pre‐assembly process that used a near‐infrared fluorescent squaraine dye to thread a macrocycle bearing a cancer targeting unit. Cell microscopy studies using OVCAR‐4 (ovarian cancer) and A549 (lung cancer) cells that express high levels of the integrin αvβ3 or αvβ5 receptors,...

Two macrocyclic tetralactam receptors are shown to selectively encapsulate anionic, square planar chloride and bromide coordination complexes of gold(III), platinum(II), or palladium(II). Both receptors have a preorganized structure that is complementary to its precious metal guest. The receptors do not directly ligate the guest metal center but in...

One of the major goals of modern supramolecular chemistry, with important practical relevance in many technical fields, is the development of synthetic host/guest partners with ultrahigh affinity and selectivity in water. Currently, most association pairs exhibit micromolar affinity or weaker, and there are very few host/guest systems with Ka > 109...

While the general concept of steric speed bumps has been demonstrated in rotaxane shuttles and macrocycle threading systems, the sensitivity of speed bump effects has not been evaluated as a function of structural geometry. Values of Ka and kon for macrocycle threading in water are reported for a series of homologous squaraine dyes with different s...

A new self-assembly method is used to rapidly functionalize the surface of liposomes without perturbing the membrane integrity or causing leakage of the aqueous contents. The key molecule is a cholesterol-squaraine-PEG conjugate with three important structural elements: a cholesterol membrane anchor, a fluorescent squaraine docking station that all...

A conceptually new type of enzymatic cleavage assay is reported that utilizes in-situ supramolecular capture of the fluorescent product. A squaraine-derived substrate with large blocking groups at each end of its structure cannot be threaded by a tetralactam macrocycle until the blocking groups are removed by enzyme cleavage. A prototype design res...

A robust approach is developed to prepare hyperstar polymer-Au25(SR)18 nanocomposites for catalysis. The synthesis started with atom transfer radical copolymerization of an inimer with a cyclic disulfide-containing methacrylate monomer in a microemulsion to produce hyperbranched copolymers with high molar mass, low polydispersity, and a vital fract...

Biotin/(strept)avidin self-assembly is a powerful platform for nanoscale fabrication and capture with many different applications in science, medicine, and nanotechnology. However, biotin/(strept)avidin self-assembly has several well-recognized drawbacks that limit performance in certain technical areas and there is a need for synthetic mimics that...

Croconaine dyes have narrow and intense absorption bands at ~800 nm, very weak fluorescence, and high photostabilities, which combine to make them very attractive chromophores for absorption-based imaging or laser heating technologies. The physical supramolecular properties of croconaine dyes have hardly been investigated, especially in water. This...

A macrocyclic tetralactam is threaded by a complementary squaraine dye that is flanked by two polyethylene glycol chains to produce a pseudorotaxane complex with favorable near-infrared fluorescence properties. The association thermodynamics and kinetics were measured for a homologous series of squaraines with different N-alkyl substituents at both...

A macrocyclic tetralactam host is threaded by a highly fluorescent squaraine dye that is flanked by two polyethyleneglycol (PEG) chains with nanomolar dissociation constants in water. Furthermore, the rates of bimolecular association are very fast with kon ~10(6)-10(7) M(-1)s(-1). The association is effective under cell culture conditions and produ...

We reported a supramolecular system consisted of β-cyclodextrin, N,N-dimethylformamide and LiCl, which could exhibit different behaviors toward various alcohols. When some liquid monohydric alcohols were injected into the system at room temperature, a semitransparent organogel (the ambient temperature organogel) was formed. Compared with liquid mon...

This paper describes a novel double phase transforming organogel (gel-sol-gel') composed of nontoxic β-cyclodextrin, potassium carbonate, and 1,2-propylene glycol. The gel-sol-gel' transforming processes are followed by a reversible gel-sol transforming process and an irreversible sol-gel' transforming process based on heating. The gel-sol-gel' tra...