Nanoarchitectonics with porphyrins and related molecules

An emerging concept, nanoarchitectonics, is supposed to work on the preparation of functional materials systems from nanoscale components. Because porphyrin derivatives show their importance in many research targets, discussions on nanoarchitectonics with porphyrins and related molecules would provide meaningful opportunities to consider effective usages of the nanoarchitectonics. This review article explains various examples of nanoarchitectonics approaches with porphyrin derivatives. The examples are especially focused on two topics: (i) materials nanoarchitectonics for nanofibers, metal-organic frameworks, covalent organic frameworks, and hydrogen-bonded organic frameworks; (ii) interfacial nanoarchitectonics for surface monolayers (self-assembled monolayers), Langmuir-Blodgett films, and layer-by-layer assemblies. Functions and properties can be enhanced upon their organization in specific dimensions and arrangements in nanostructured frameworks. In many cases, interface-specific organization would lead to advanced performances with high efficiency and specificity. Even though only limited examples are described here, various possibilities are actually suggested. Not limited to porphyrin families, nanoarchitectonics for functional materials has to be considered with a wide range of materials.

Predicting human touch sensitivity to single atom substitutions in surface monolayers for molecular control in tactile interfaces

We control the sense of touch through materials chemistry. To find tactile materials, we developed methods to screen materials and found that humans could distinguish surface monolayers which differed by a single atom substitution.

Precision at the nanoscale: on the structure and property evolution of gold nanoclusters

Chemists are often regarded as “architects”, who are capable of building up complex molecular structures in the ultrasmall-dimensional world. However, compared with organic chemistry, nanochemistry – which deals with nanoparticles in the size range from 1 to 100 nm – is less precise in terms of synthesis, composition, and structure. Such an imprecise nature of nanochemistry has impeded an in-depth understanding as well as rational control of structures and properties of nanomaterials. Motivated by this, thiolate-protected gold nanoclusters (denoted as Aun(SR)m) have recently emerged as a paradigm of atomically precise nanomaterials, in which all the nanoparticles are identical to each other with the same number of core atoms (n) and surface ligands (m) as well as the atomic arrangement. In this review, we provide a demonstration of how the precise nature of Aun(SR)m nanoclusters allows one to understand, decipher and discover some important, enigmatic and intriguing issues and phenomena in nanoscience, including (i) a precise nanoscale transformation reaction induced by surface ligand exchange, (ii) the total structures of crystalline metal phases and the self-assembled surface monolayers, (iii) the periodicities and quantum confinement in nanoclusters and (iv) the emergence of hierarchical complexity in the entire nanoparticle system. We expect that such an in-depth understanding will eventually lead to the rational design and precise engineering of complex architectures at the nanoscale.

Role of fingerprint-inspired relief structures in elastomeric slabs for detecting frictional differences arising from surface monolayers

Fingerprint-inspired relief structures increase differences in friction when sliding across hydrophobic and hydrophilic surfaces.