title: Host-Guest Chemistry in Integrated Porous Space Formed by Molecular Self-Assembly at Liquid-Solid Interfaces.
abstract: Host-guest chemistry in two-dimensional (2D) space, that is, physisorbed monolayers of a single atom or a single molecular thickness on surfaces, has become a subject of intense current interest because of perspectives for various applications in molecular-scale electronics, selective sensors, and tailored catalysis. Scanning tunneling microscopy has been used as a powerful tool for the visualization of molecules in real space on a conducting substrate surface. For more than a decade, we have been investigating the self-assembly of a series of triangle-shaped phenylene-ethynylene macrocycles called dehydrobenzo[12]annulenes (DBAs). These molecules are substituted with six alkyl chains and are capable of forming hexagonal porous 2D molecular networks via van der Waals interactions between interdigitated alkyl chains at the interface of organic solvents and graphite. The dimension of the nanoporous space or nanowell formed by the self-assembly of DBAs can be controlled from 1.6 to 4.7 nm by simply changing the alkyl chain length from C6to C20. Single molecules as well as homoclusters and heteroclusters are capable of coadsorbing within the host matrix using shape- and size-complementarity principles. Moreover, on the basis of the versatility of the DBA molecules that allows chemical modification of the alkyl chain terminals, we were able to decorate the interior space of the nanoporous networks with functional groups such as azobenzenedicarboxylic acid for photoresponsive guest adsorption/desorption or fluoroalkanes and tetraethylene glycol groups for selective guest binding by electrostatic interactions and zinc-porphyrin units for complexation with a guest by charge-transfer interactions. In this Feature Article, we describe the general aspects of molecular self-assembly at liquid/solid interfaces, followed by the formation of programmed porous molecular networks using rationally designed molecular building blocks. We focus on our own work involving host-guest chemistry in integrated nanoporous space that is modified for specific purposes.
authors.affiliation: Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka 560-8531, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Iritani
authors.affiliation: Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka 560-8531, Japan.|Department of Applied Chemistry, School of Science and Technology, Meiji University , Kawasaki, Kanagawa 214-8571, Japan.
authors.forename: Kazukuni
authors.initials: K
authors.lastname: Tahara
authors.affiliation: Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven - University of Leuven , Celestijnenlaan 200F, 3001 Leuven, Belgium.
authors.forename: Steven
authors.initials: S
authors.lastname: De Feyter
authors.affiliation: Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka 560-8531, Japan.
authors.forename: Yoshito
authors.identifier: 0000-0002-1795-5829
authors.initials: Y
authors.lastname: Tobe