2D hexagonal assembly of a dipolar rotor with a close interval of 0.8 nm using a triptycene-based supramolecular scaffold.

Controlling the rotation of carbon-carbon bonds, which is ubiquitous in organic molecules, to create functionality has been a subject of interest for a long time. In this context, it would be interesting to explore whether cooperative and collective rotation could occur if dipolar molecular rotors were aligned close together while leaving adequate space for rotation. However, it is difficult to realize such structures as bulk molecular assemblies, since molecules generally tend to assemble into the closest packing structure to maximize intermolecular forces.

Rewriting the phase diagram of a diamagnetic liquid crystal by a magnetic field.

Magnetic fields have been considered to only interact with organic materials non-destructively, leaving their fundamental structures unaffected, even when a strong magnetic field generated from a superconducting magnet is applied. Here we report an unprecedented observation that a liquid-crystalline mesophase of a diamagnetic molecular assembly with an orthorhombic or a cubic structure is formed selectively in the absence or presence of a strong magnetic field. The constituent molecule is a triphenylene derivative carrying six imidazolium bromide-terminated alkyl side chains and exhibits a cubic, orthorhombic, or hexagonal columnar mesophase when complexed with an appropriate amount of lanthanum(III) bromide.

Boron-mediated sequential alkyne insertion and C-C coupling reactions affording extended π-conjugated molecules.

C-C bond coupling reactions illustrate the wealth of organic transformations, which are usually mediated by organotransition metal complexes. Here, we show that a borafluorene with a B-Cl moiety can mediate sequential alkyne insertion (1,2-carboboration) and deborylation/Csp(2)-Csp(2) coupling reactions, leading to aromatic molecules. The first step, which affords a borepin derivative, proceeds very efficiently between the borafluorene and various alkynes by simply mixing these two components.

Bioinspired design of a polymer gel sensor for the realization of extracellular Ca(2+) imaging.

Although the role of extracellular Ca(2+) draws increasing attention as a messenger in intercellular communications, there is currently no tool available for imaging Ca(2+) dynamics in extracellular regions. Here we report the first solid-state fluorescent Ca(2+) sensor that fulfills the essential requirements for realizing extracellular Ca(2+) imaging. Inspired by natural extracellular Ca(2+)-sensing receptors, we designed a particular type of chemically-crosslinked polyacrylic acid gel, which can undergo single-chain aggregation in the presence of Ca(2+).

Ferromagnetic spin coupling between endohedral metallofullerene La@C82 and a cyclodimeric copper porphyrin upon inclusion.

The cyclic host cyclo-[P(Cu)](2) carrying two covalently connected Cu(II) porphyrin units can accommodate La@C(82), a paramagnetic endohedral metallofullerene, in its cavity to form the inclusion complex cyclo-[P(Cu)](2)⊃La@C(82), which can be transformed into the caged complex cage-[P(Cu)](2)⊃La@C(82) by ring-closing olefin metathesis of its side-chain olefinic termini. On the basis of electron spin resonance (ESR) and electron spin transient nutation (ESTN) studies, cyclo-[P(Cu)](2)⊃La@C(82) is the first ferromagnetically coupled inclusion complex featuring La@C(82), whereas cage-[P(Cu)](2)⊃La@C(82) is ferrimagnetic.

Single molecular observation of penta- and hexagonic assembly of bisporphyrin on a gold surface.

Artificial light-harvesting antennae of coordination-organized macrocyclic porphyrin pentamer and hexamer are visualized by high resolution scanning tunneling microscopy (HRSTM) on a gold surface.

Assemblies of supramolecular porphyrin dimers in pentagonal and hexagonal arrays exhibiting light-harvesting antenna function.

Porphyrin-based supramolecular macrocyclic arrays were synthesized as mimics of photosynthetic light-harvesting (LH) antennae. Pentameric and hexameric macrocyclic porphyrin arrays EP5 and EP6 were constructed by complementary coordination of m-bis(ethynylene)phenylene-linked zinc-imidazolylporphyrin Zn-EP-Zn. The proton NMR spectra of noncovalently linked N-EP5 and N-EP6 indicate fast rotation of the porphyrin moieties along the ethyne axis.