Michito Yoshizawa

The application of self-assembled hosts as "molecular flasks" has precipitated a surge of interest in the reactivity and properties of molecules within well-defined confined spaces. The facile and modular synthesis of self-assembled hosts has enabled a variety of hosts of differing sizes, shapes, and properties to be prepared. This Review briefly highlights the various molecular flasks synthesized before focusing on their use as functional molecular containers--specifically for the encapsulation

Self-assembled, hollow molecular structures are appealing as synthetic hosts for mediating chemical reactions. However, product binding has inhibited catalytic turnover in such systems, and selectivity has rarely approached the levels observed in more structurally elaborate natural enzymes. We found that an aqueous organopalladium cage induces highly unusual regioselectivity in the Diels-Alder coupling of anthracene and phthalimide guests, promoting reaction at a terminal rather than central ant

Abstract Auf kleinstem Raum : Selbstorganisierte Wirtmoleküle können als „molekulare Reaktionskolben“ die Reaktivitäten und Eigenschaften von Gastmolekülen verändern, die den räumlichen Einschränkungen ihrer wohldefinierten Hohlräume ausgesetzt sind. Vielfältige funktionale Wirte mit unterschiedlichen Größen, Formen und Anwendungsmöglichkeiten wurden mithilfe der einfachen, modularen Konzepte der supramolekularen Chemie hergestellt. magnified image Der Einsatz von selbstorganisierten Wirtmolekül

Molecular flasks of self-assembled M6L4 nanocages promote the [2+2] photodimerization of olefins in a surprisingly efficient fashion. Thus, the dimerization of acenaphthylenes and naphthoquinones quantitatively proceeded in the cavity with remarkable rate acceleration and perfect regio- and stereocontrol (>98 %, see scheme). Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2002/z18306_s.pdf or from the author. Please note: The publish

Anthracene, with its molecular panel-like shape and robust photophysical behaviour, is a versatile building block that is widely used to construct attractive and functional molecules and molecular assemblies through covalent and non-covalent linkages. The intrinsic photophysical, photochemical and chemical properties of the embedded anthracenes often interact to engender desirable chemical behaviours and properties in multi-anthracene assemblies. This review article focuses on molecular architec

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTShip-in-a-Bottle Synthesis of Otherwise Labile Cyclic Trimers of Siloxanes in a Self-Assembled Coordination CageMichito Yoshizawa, Takahiro Kusukawa, Makoto Fujita, and Kentaro YamaguchiView Author Information Department of Applied Chemistry Graduate School of Engineering, Nagoya University CREST, Japan Science and Technology Corporation (JST) Chikusaku, Nagoya 464-8603, Japan Chemical Analysis Center, Chiba University Inageku, Chiba 263-8522, Ja

An adamantanoid (H2O)10 cluster is formed within the hydrophobic cavity of a self-assembled coordination cage. This cluster is termed "molecular ice" because it is the smallest unit of naturally occurring Ic-type ice. X-ray structural analysis, coupled with neutron diffraction study, reveals that the molecular ice is formed not by a simple space-filling effect but by efficient molecular recognition within the cage via H2O:...pi interaction.

Metal-hinged, organic-pillared cages accommodate a limited number (n) of π-stacked molecules in the cavity (see scheme): Discrete n+2 aromatic stacking occurs by the accommodation of n large aromatic guests (n=1–3). Owing to efficient donor–acceptor (D–A) interactions, A–D–A (n=1), A–D–D–A (n=2), and A–D–A–D–A (n=3) stacks are observed, which bring about even–odd-number effects in the UV/Vis absorption spectra. Supporting information for this article is available on the WWW under http://www.wile

This Account provides a comprehensive summary of our 1-decade-long investigations into bent anthracene dimers as versatile building blocks for supramolecular capsules. The investigations initiated in 2008 with the design of an anthracene dimer with a <i>meta</i>-phenylene spacer bearing two substituents on the convex side. Using the bent polyaromatic building block, we began to develop novel supramolecular capsules from two different synthetic approaches. One is a coordination approach, which wa

The photoexcitation of a self-assembled M6L4-type coordination cage accommodating photochemically inert alkane guests (e.g., adamantane and cyclooctane) led to the regioselective oxidation of the guest within the cage. Under anaerobic conditions, the guest oxidation was accompanied by the stable radical formation as indicated by ESR spectrometry (g = 2.002) and change in solution color (from colorless to blue). These phenomena were shown to be characteristic of the self-assembled molecular syste

Herein reported is the highly selective [2 + 2] cross-photodimerization of olefins within a self-assembled coordination cage that acts as a molecular flask in an aqueous medium. An M(6)L(4) coordination nanocage that self-assembles from six Pd(II) complexes and four tridentate ligands accommodates two different kinds of large olefin molecules such as acenaphthylene and 5-ethoxynaphthoquinone in a pairwise selective fashion. This prerequisite recognition mode makes possible the selective [2 + 2]

A mixed-valence state of the cation radical tetrathiafulvalene dimer, [(TTF)2]+*, is generated by the electrochemical oxidation of a stacked TTF dimer accommodated within an organic-pillared coordination cage. This mixed-valence species is remarkably stable (t1/2 = approximately 1 day at room temperature in aqueous solution under air) and clearly characterized by cyclic voltammogram and electronic absorption spectroscopy.

This paper introduces a concept that is referred to as cavity-directed synthesis by showing the selective oligomerization of trialkoxysilanes, RSi(OMe)3 (7), in self-assembled hollow compounds. Pd(II)-linked coordination hosts (cage, bowl, or tube) are found to strictly control the oligomerization of 7 (R = 2-naphthyl) in such a way that their optimal guests are produced in their cavities. Thus, within coordination tube 1, one molecule of 7 is accommodated and subsequently hydrolyzed to give sil

An M2L4 coordination capsule or an M2L2 coordination tube was selectively formed by the combination of Hg(II) hinges and bent bispyridine ligands. The two structures reversibly interconvert at room temperature in response to modulation of the metal-to-ligand ratio and exhibit different host-guest interaction behavior. The capsule alone encapsulates large spherical molecules, fullerenes C60 and C70, and the bound guests are released upon capsule-to-tube transformation by the simple addition of me

cis-Decalin (2) and perylene (3) are co-enclathrated by a self-assembled M6L4-coordination cage (1) to give 1 superset(2.3) although each of them is not enclathrated. This phenomenon is termed as AND bimolecular recognition because enclathration occurs only if 2 and 3 coexist. Cage 1 also coenclathrates azulene (8) and 1,4-naphthoquinone (9) to give 1 superset(8.9). In this case, 1 superset(8)2 and 1 superset(9)2 are formed by treating 1 with 8 and 9 individually. This case is termed as OR bimol