An Efficient Near-Infrared Emissive Artificial Supramolecular Light-Harvesting System for Imaging in the Golgi Apparatus.

Light-harvesting systems are an important way for capturing, transferring and utilizing light energy. It remains a key challenge to develop highly efficient artificial light-harvesting systems. Herein, we report a supramolecular co-assembly based on lower-rim dodecyl-modified sulfonatocalix[4]arene (SC4AD) and naphthyl-1,8-diphenyl pyridinium derivative (NPS) as a light-harvesting platform. NPS as a donor shows significant aggregation induced emission enhancement (AIEE) after assembling with SC4AD. Upon introduction of Nile blue (NiB) as an acceptor into the NPS-SC4AD co-assembly, the light-harvesting system becomes near-infrared (NIR) emissive (675 nm). Importantly, the NIR emitting NPS-SC4AD-NiB system exhibits an ultrahigh antenna effect (33.1) at a high donor/acceptor ratio (250:1). By co-staining PC-3 cells with a Golgi staining reagent, NBD C6 -ceramide, NIR imaging in the Golgi apparatus has been demonstrated using these NIR emissive nanoparticles.

Metal-free synthesis of imino-disaccharides and calix-iminosugars by photoinduced radical thiol-ene coupling (TEC).

Radical thiol-ene coupling was exploited for the first time to prepare imino-disaccharides and multivalent iminosugars starting from sugar thiols and iminosugar alkenes or iminosugar thiols and tetra-allylated calixarene, respectively.

Exploring the magnetic behavior of nickel-coordinated pyrogallol[4]arene nanocapsules.

The magnetic behavior of nickel-seamed C-propylpyrogallol[4]arene dimeric and hexameric nanocapsular assemblies has been investigated in the solid state using a SQUID magnetometer. These dimeric and hexameric capsular entities show magnetic differentiation both in terms of moment per nanocapsule and potential antiferromagnetic interactions within individual nanocapsules. The weak antiferromagnetic behavior observed at low temperatures indicates dipolar interactions between neighboring nickel atoms; however, this effect is higher in the hexameric nickel-seamed assembly. The differences in magnetic behavior of dimer versus hexamer can be attributed to different coordination environments and metal arrangements in the two nanocapsular assemblies.

Two related lithium calixarene complexes, [p-tert-butylcalix[4]arene(OMe)(OH)2(OLi)](2).4MeCN and {p-tert-butylcalix[4]arene(OH)2(OLi)[OLi(NCMe)2]}(2).8MeCN, determined using synchrotron radiation.

The crystal structures of acetonitrile solvates of two related lithium calixarene complexes have been determined by low-temperature single-crystal X-ray diffraction using synchrotron radiation. Bis(mu-5,11,17,23-tetra-tert-butyl-26,28-dihydroxy-25-methoxy-27-oxidocalix[4]arene)dilithium(I) acetonitrile tetrasolvate, [Li2(C45H57O4)2].4C2H3N or [p-tert-butylcalix[4]arene(OMe)(OH)2(OLi)](2).4MeCN, (I), crystallizes with the complex across a centre of symmetry and with four molecules of unbound acetonitrile of crystallization per complex. Tetraacetonitrilebis(mu-5,11,17,23-tetra-tert-butyl-26,28-dihydroxy-25,27-dioxidocalix[4]arene)tetralithium(I) acetonitrile octasolvate, [Li4(C44H54O4)2(C2H3N)4].8C2H3N or {p-tert-butylcalix[4]arene(OH)2(OLi)[OLi(NCMe)2]}(2).8MeCN, (II), also crystallizes with the complex lying across a centre of symmetry and contains eight molecules of unbound acetonitrile per complex plus four more directly bound to two of the lithium ions, two on each ion. The cores of both complexes are partially supported by O-H...O hydrogen bonds. The methoxy methyl groups in (I) prevent the binding of any more than two Li+ ions, while the corresponding two O-atom sites in (II) bind an extra Li(+) ion each, making four in total. The calixarene cone adopts an undistorted cone conformation in (I), but an elliptical one in (II).

Nano-supramolecular assemblies constructed from water-soluble bis(calix[5]arenes) with porphyrins and their photoinduced electron transfer properties.

Possessing 2D netlike and 1D linear morphologies, two nano-supramolecular architectures A1 and A2 are constructed by tetracationic porphyrin (G1) and dicationic porphyrin (G2), respectively, upon complexation with the novel water-soluble bis(p-sulfonatocalix[5]arenes) bridged at the lower rim (H2). Corresponding to the molecular design, the aggregation morphologies are well manipulated by the inherent binding sites of the building blocks through host-guest interactions as well as charge interactions. In comparison to the simple p-sulfonatocalix[5]arene H1 which can only form particle-type complexes C1 and C2 with porphyrin guests, H2 provides excellent pre-organized structure to construct highly complex nano-supramolecular assemblies. The exhibited electron-transfer process of the supramolecular systems is further investigated by steady-state and time-resolved fluorescence spectroscopy, electrochemical measurements, and transient absorption spectroscopy. The results obtained show that calixarenes are also effective electron donors in PET besides acting as significant building blocks, which gives them many advantages in constructing well-ordered nanomaterials with the capability of electron and energy transport.

Reverse engineering of an affinity-switchable molecular interaction characterized by atomic force microscopy single-molecule force spectroscopy.

Tunable and switchable interaction between molecules is a key for regulation and control of cellular processes. The translation of the underlying physicochemical principles to synthetic and switchable functional entities and molecules that can mimic the corresponding molecular functions is called reverse molecular engineering. We quantitatively investigated autoinducer-regulated DNA-protein interaction in bacterial gene regulation processes with single atomic force microscopy (AFM) molecule force spectroscopy in vitro, and developed an artificial bistable molecular host-guest system that can be controlled and regulated by external signals (UV light exposure and thermal energy). The intermolecular binding functionality (affinity) and its reproducible and reversible switching has been proven by AFM force spectroscopy at the single-molecule level. This affinity-tunable optomechanical switch will allow novel applications with respect to molecular manipulation, nanoscale rewritable molecular memories, and/or artificial ion channels, which will serve for the controlled transport and release of ions and neutral compounds in the future.