Biofuel-Driven Stepping Chiral Supramolecular Transfer Container.

Herein, we reported a biofuel-driven recyclable chiral supramolecular transfer container based on hexacationic triphenylamine cage and nucleotides. Possessing rotatable paddle rigid backbones, the artificial receptor effectively encapsulated nucleotides with a high binding constant up to 5.37×10 M in water, displaying guest-induced efficient fluorescence enhancement with quantum yield increased from 6.

Supramolecular assembly activated single-molecule phosphorescence resonance energy transfer for near-infrared targeted cell imaging.

Pure organic phosphorescence resonance energy transfer is a research hotspot. Herein, a single-molecule phosphorescence resonance energy transfer system with a large Stokes shift of 367 nm and near-infrared emission is constructed by guest molecule alkyl-bridged methoxy-tetraphenylethylene-phenylpyridines derivative, cucurbit[n]uril (n = 7, 8) and β-cyclodextrin modified hyaluronic acid. The high binding affinity of cucurbituril to guest molecules in various stoichiometric ratios not only regulates the topological morphology of supramolecular assembly but also induces different phosphorescence emissions.

Inclusion-Activated Reversible / Isomerization of a Cyanostilbene Derivative Based on Cucurbit[8]uril under 365 nm Ultraviolet Irradiation.

The photoisomerization behavior of cyanostilbene molecules is a hotspot in supramolecular configuration transformation research. Here, we reported a cyanostilbene derivative that converted from the ,-isomer to the ,-isomer under UV light irradiation at 365 nm. This process can be reversibly converted only in the presence of cucurbit[8]uril under the same light source, accompanied by the reversible conversion of fluorescence from green to yellow.

Guest-induced supramolecular chirality transfer in [2]pseudorotaxanes: experimental and computational study.

To reveal the factors governing the chirality transfer from a chiral unimolecule to a supramolecular assembly, we constructed a series of [2]pseudorotaxanes through the intermolecular noncovalent interaction of a pair of chiral binaphthalene crown ethers with achiral secondary ammonium salts with different chromophores, and found that the binaphthalene groups can induce new circular dichroism (CD) signals only in the [2]pseudorotaxane structures between the host crown ethers and the guest molecule with the anthryl group. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations show that the generation of the new CD signal is mainly due to the intermolecular chiral induction between the anthryl group in the guest and the naphthalene groups in the host.

Photo-controlled chirality transfer and FRET effects based on pseudo[3]rotaxane.

The use of light to regulate the chirality of supramolecular assemblies in a non-invasive manner remains a challenge. Herein, we report a novel photochromic pseudo[3]rotaxane based on a (R/S)-2,2'-binaphthyl secondary ammonium salt guest (2) and anthracene-bridged bis(dibenzo-24-crown-8) (1), which features a chirality transfer and fluorescence resonance energy transfer (FRET) from 2 to 1. Benefiting from the photo-oxidation of anthracene, the induced circular dichroism (ICD) signals of (R/S)-2@1 can be switched off/on by irradiation with 365 nm UV light and heating.

Photocontrolled morphological conversion and chiral transfer of a snowflake-like supramolecular assembly based on azobenzene-bridged bis(dibenzo-24-crown-8) and a cholesterol derivative.

A snowflake-like supramolecular clockwise-helical assembly was fabricated via the host-guest interaction of trans-azobenzene-bridged bis(dibenzo-24-crown-8) (trans-1) and a cholesterol derivative, while a snowflake-like supramolecular non-helical assembly can be obtained upon complexation of cis-1 after UV-irradiation, accompanying the disappearance of circular dichroism signals from the azobenzene zone of 1.

Light-controlled reversible self-assembly of nanorod suprastructures.

Nanorod suprastructures constructed by the coordination of zinc ions with the inclusion complex of 4,4'-dipyridine in β-cyclodextrin can dissociate and rebuild repeatedly via alternate visible light irradiation in the presence of photoacid merocyanine in aqueous solution.

Tunable Luminescent Lanthanide Supramolecular Assembly Based on Photoreaction of Anthracene.

Lanthanide luminescence materials generally show great superiority in light-emitting materials, gaining increasingly exploration in the design of advanced functional materials. Herein, we prepared a supramolecular assembly via the coordination of a host molecule (1) and dilanthanide metal. Compound 1 possesses a 9,10-diphenylanthracene (ant) core with photosensitivity and terminal terpyridine (tpy), containing two-arm dibenzo-24-crown-8.

A supramolecular brush polymer via the self-assembly of bridged tris(β-cyclodextrin) with a porphyrin derivative and its magnetic resonance imaging.

Accurate imaging of soft tissues is one of the ultimate goals in biomedical imaging. Different imaging modalities can improve their disadvantages, and promote the imaging ability. However, once an imaging agent has been prepared, it is usually hard to adjust it according to the actual needs.

Fluorescent supramolecular polypseudorotaxane architectures with Ru(II)/tri(bipyridine) centers as multifunctional DNA reagents.

A water-soluble supramolecular polypseudorotaxane was prepared via the host-guest interaction of cucurbit[8]uril and the Ru(bpy)3 complex with bis-naphthalene groups. By employing the intrinsic properties of the Ru(bpy)3 complex, the linear polypseudorotaxane can induce DNA condensation, be used as an inhibitor for DNA cleavage enzymes, and trace the translocation of DNA into 293T cells efficiently.

Mechanically selflocked chiral gemini-catenanes.

Mechanically interlocked and entangled molecular architectures represent one of the elaborate topological superstructures engineered at a molecular resolution. Here we report a methodology for fabricating mechanically selflocked molecules (MSMs) through highly efficient one-step amidation of a pseudorotaxane derived from dual functionalized pillar[5]arene (P[5]A) threaded by α,ω-diaminoalkane (DA-n; n=3-12). The monomeric and dimeric pseudo[1]catenanes thus obtained, which are inherently chiral due to the topology of P[5]A used, were isolated and fully characterized by NMR and circular dichroism spectroscopy, X-ray crystallography and DFT calculations.

Light-controlled reversible formation and dissociation of nanorods via interconversion of pseudorotaxanes.

Nanorod-like supramolecular aggregates are fabricated by the self-assembly of the amphiphilic [2]pseudorotaxane, which can be dissociated and rebuilt by the alternating UV/vis irradiation.

Supramolecular nanoassemblies of an amphiphilic porphyrin-cyclodextrin conjugate and their morphological transition from vesicle to network.

An amphiphilic compound, 5-(4'-dodecyloxyphenyl)-10,15,20-tri(permethyl-β-CD)-modified Zn(II)-porphyrin (1; β-CD = β-cyclodextrin), was synthesized by means of the click reaction of an alkylated Zn-porphyrin derivative with 6-deoxy-6-azidopermethyl-β-CD. The complexation between 1 and tetrasodium tetraphenylporphyrintetrasulfonate (5) with different molar ratios led to the formation of two distinctly different nanoarchitectures, which were proven to be vesicle and network aggregates, respectively, by using dynamic light scattering, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. On the basis of the results of the time-dependent TEM studies, fluorescence, and NMR spectroscopic measurements, we have determined that the mechanism of the morphology transition from vesicles to networks is controlled by the stepwise complexation of 1 with 5.

Dual-stimulus luminescent lanthanide molecular switch based on an unsymmetrical diarylperfluorocyclopentene.

A [2]pseudorotaxane formed from an unsymmetrical diarylperfluorocyclopentene (1) and a Eu(3+) complex of terpyridinyldibenzo-24-crown-8 (2) revealed excellent reversible lanthanide luminescence switching behavior dual-modulated by host-guest and optical stimuli.

A double-leg donor-acceptor molecular elevator: new insight into controlling the distance of two platforms.

A double-leg elevator with an electron-rich anthracene moiety at the platformlike component and an electron-deficient naphthalenediimide unit in the middle of a double-leg riglike component was prepared through "click chemistry", in which the reversible elevator movement between different levels could be controlled upon the addition of base and acid.

Self-sorting of four organic molecules into a heterowheel polypseudorotaxane.

The social self-sorting supramolecular assembly is described by non-covalent interactions among four organic components. Toward this goal, a series of self-sorting systems have been investigated by mixing two or three different compounds; naphthyl-bridged bis(α-cyclodextrin), N,N'-dioctyl-4,4'-bipyridinium, 2,6-dihydroxynaphthalene, and cucurbit[8]uril. The influence of alkyl chains of viologen derivatives and the binding abilities of these systems have also been studied.

High affinity crown ether complexes in water: thermodynamic analysis, evidence of crystallography and binding of NAD+.

Improving traditional crown ether to the water-soluble and high binding ability host molecule is critical to our efforts to model or mimic biological supramolecular systems. In this paper, we converted two traditional crown ethers, 1,5-dinaphtho-32-crown-8 and 1,5-dinaphtho-38-crown-10, into the water-soluble tetrasulfonated 1,5-dinaphtho-32-crown-8 and tetrasulfonated 1,5-dinaphtho-38-crown-10, evaluated their complexation with three dicationic bipyridiniums in aqueous solution by microcalorimetric titration, UV-vis, and NMR experiments, and then determined the crystal structures of three tetrasulfonatocrown ether-bipyridinium complexes. The equilibrium association constants of tetrasulfonated 1,5-dinaphtho-32-crown-8 with these bipyridiniums reach up to 10(7) M(-1), while those of tetrasulfonated 1,5-dinaphtho-38-crown-10 are just in the range of 10(5) M(-1) order of magnitude.

Interconversion between [5]pseudorotaxane and [3]pseudorotaxane by pasting/detaching two axle molecules.

An acceptor-donor-acceptor-type linear molecule 1(2+) containing one electron-rich naphthoxy (NP) unit and two monocharged viologen (MCV) units was synthesized. Through the noncovalent interaction of cucurbit[8]uril (CB[8]) with one NP and one MCV in 1(2+), we first obtained a [2]pseudorotaxane ([1(2+)]⊂CB[8]), and the excess CB[8] included simultaneously the two bare MCV units of two [2]pseudorotaxanes to form a [5]pseudorotaxane ([1(2+)](2)⊂[CB[8]](3)). Its transformation to [3]pseudorotaxane was achieved through detaching the two axle molecules in the presence of acid, and then the addition of base may result in a reversible switch between two different pseudorotaxanes.

[The study on local field potentials in rat's primary motor cortex during pressing paddle behavior].

Objective: The local field potential (LFP) is a summation of dendritic potentials. The main objective of the present work is to view the features of LFP in M1 during the experimental rat pushed a paddle with the right forelimb.

Methods: Four rats were trained to press a paddle with the right forelimb for water.

A heterowheel [3]pseudorotaxane by integrating β-cyclodextrin and cucurbit[8]uril inclusion complexes.

A heterowheel [3]pseudorotaxane was prepared by integrating two binary inclusion complexes of β-cyclodextrin-hydroxynaphthalene (β-CD·3) with a cucurbit[8]uril-viologen derivative (CB[8]·2), in which simultaneous molecular recognition of the adamantine moiety in 2 by β-CD and the charge-transfer interaction of 3 with the viologen nucleus of 2 in the cavity of CB[8] are two crucial factors for the formation of the quaternary complex.

Coordination-induced switchable nanoparticle formation from naphthyl-bridged bis(β-cyclodextrin).

Naphthyl-bridge bis(β-cyclodextrin) (1) was synthesized via "click chemistry", and its self-assembly behavior was investigated by NMR, UV-vis, circular dichroism spectra, transmission electron microscopy, and atomic force microscopy. The results obtained indicate that the coordination of Hg(2+) with triazole rings in 1 induces the naphthyl moiety to move from being a self-included complex to the formation of nanoparticles through intermolecular self-aggregation. Furthermore, the formation and disassembly of nanoparticle was reversibly controlled by adding or removing Hg(2+).

Thermodynamic origin of selective binding of β-cyclodextrin derivatives with chiral chromophoric substituents toward steroids.

Two β-cyclodextrin derivatives with chiral chromophoric substituents, that is, L- (1) and D-tyrosine-modified β-cyclodextrin (2), were synthesized and fully characterized. Their inclusion modes, binding abilities, and molecular selectivities with four steroid guests, that is, cholic acid sodium salt (CA), deoxycholic acid sodium salt (DCA), glycochoic acid sodium salt (GCA), and taurocholic acid sodium salt (TCA), were investigated by the circular dichroism, 2D NMR, and isothermal titration microcalorimetry (ITC). The results obtained from the circular dichroism and 2D NMR showed that two hosts adopted the different binding geometry, and these differences subsequently resulted in the significant differences of molecular binding abilities and selectivities.