A mechanical switch in a [2]catenane, made up of cyclobis(paraquat-p-phenylene) tetracation interlocked with macrocyclic polyether containing redox-active tetrathiafulvalene (TTF) unit and 1,5-dioxynaphthalene ring system, can be thrown either chemically or electrochemically. The neutral TTF resides "inside" the tetracationic cyclophane reduced state "alongside" it oxidized species (TTF+/ TTF2+). Switching between (I4+) (I5+(I6+)) is accompanied by dramatic color change.

ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTImproved Template-Directed Synthesis of Cyclobis(paraquat-p-phenylene)Masumi Asakawa, Wim Dehaen, Gerrit L'abbé, Stephan Menzer, Jan Nouwen, Françisco M. Raymo, J. Fraser Stoddart, and David WilliamsView Author Information School Chemistry, University Birmingham, Edgbaston, Birmingham B15 2TT, U.K., Department Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium, Imperial College, South Kensington, London SW7 2AY, U.K. Cite this: Org. Chem. 1996,...

Abstract The electrochemical and spectroscopic properties of a pseudorotaxane formed in acetonitrile solution by self‐assembly wire‐type electron donor based on the tetrathiafulvalene unit cyclobis(paraquat‐ p ‐phenylene) tetracationic acceptor have been investigated. We show that a) reversible dethreading/rethreading cycles can be performed either oxidation successive reduction electron‐donor wire or electron‐accepting cyclophane, b) because this special behavior, input...

A synthetic approachnamely slippageto self-assembling [n]rotaxanes incorporating π-electron deficient bipyridinium-based dumbbell-shaped components and π-electron-rich hydroquinone- and/or dioxynaphthalene-based macrocyclic polyether has been developed. The kinetics of rotaxane formation by the slipping procedure were investigated absorption UV−visible 1H-NMR spectroscopies in a range temperatures solvents, varying systematically size both stoppers components. As expected, rate constants for...

Abstract A number of nanometer‐scale molecular assemblies, based on rotaxane‐type structures, have been synthesized by means a template‐directed strategy from simple building blocks that, account the recognition arising noncovalent interactions between them, are able to self‐assemble into potential abacuses. In all cases investigated, π‐electron‐deficient tetracationic cyclophane cyclobis(paraquat‐ p ‐phenylene) is constrained mechanically around dumbbell‐shaped component consisting linear...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular recognition. 16. Molecular recognition of quinones: two-point hydrogen-bonding strategy for the construction face-to-face porphyrin-quinone architecturesYasuhiro Aoyama, Masumi Asakawa, Yuichi Matsui, and Hisanobu OgoshiCite this: J. Am. Chem. Soc. 1991, 113, 16, 6233–6240Publication Date (Print):July 1, 1991Publication History Published online1 May 2002Published inissue 1 July...

Redox-controllable molecular switches composed of two interlocking rings are incorporated here into Langmuir films starting from different redox states. The morphologies the resulting monolayers and their current–voltage characteristics then investigated. These considered to be ideal candidates for fabrication molecule-based electronic devices.

The hydrogen-bond-directed synthesis, X-ray crystal structures, and optical properties of the first chiral peptide rotaxanes are reported. Collectively these systems provide examples single molecular species where expression chirality in form a circular dichroism (CD) response can selectively be switched "on" or "off", its magnitude altered, through controlling interactions between mechanically interlocked submolecular components. switching is achievable both thermally changes nature...

This communication describes a new protocol for the construction of [2]rotaxanes: "threading-followed-by-shrinking". approach involves threading rodlike unit through crown ether-like macrocycle and then shrinking size macrocycle's cavity coordination transition-metal ion by salophen moiety in macrocycle. The self-assembly thread, followed addition palladium acetate, afforded [2]rotaxane, which contains palladium(II)-salophen moiety, after counterion exchange. [2]rotaxane was characterized...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSimultaneous hydrogen bonding and metal coordination interactions in the two-point fixation of amino acids with a bifunctional metalloporphyrin receptorYasuhiro Aoyama, Masumi Asakawa, Atsushi Yamagishi, Hiroo Toi, Hisanobu OgoshiCite this: J. Am. Chem. Soc. 1990, 112, 8, 3145–3151Publication Date (Print):April 1, 1990Publication History Published online1 May 2002Published inissue 1 April...

A range of pi-electron-rich macrocyclic polyethers incorporating dioxybenzene (hydroquinone) and/or dioxynaphthalene units have been synthesized in good yields by simple two-step procedures. These macrocycles are able to bind bipyridinium-based guests as a result series cooperative noncovalent bonding interactions. molecular recognition events can be extended the self-assembly [2]catenanes cyclophane, cyclobis(paraquat-p-phenylene), and -naphthalene units. The efficiencies these processes...

The reversible decomplexation/complexation of azobenzene-containing guests by cyclobis(paraquat-p-phenylene) has been realized the photoisomerization azobenzene unit embedded within guests. units incorporated π-electron-rich components a [2]catenane and [2]rotaxane also achieved (see figure). By contrast, in two [2]catenanes, trans→cis is quenched because electronic effects and/or prevented geometrical constraints.

Abstract Template‐directed syntheses of cyclobis(paraquat‐4,4′‐biphenylene) ( 1 )– a Molecular square –have been achieved by use π‐electron‐rich macrocyclic hydroquinone‐based and acyclic ferrocene‐based templates. In particular, the polyether‐disubstituted ferrocene derivative as template permits synthesis (which is accessible only in very low yields without templates) on preparative scale. Furthermore, polyether corporating an ester function one chain–an (oriented) macrocycle–affords :...

Monolayer arrays of a series meso-tetra-substituted porphyrins containing octadecyloxy and carboxyl (or pyridyl) groups were prepared on the highly oriented pyrolytic graphite surface at liquid/solid interface. It was found by means scanning tunneling microscopy that some from this family assemble into various patterns. Specifically, slightly undulated rows are obtained 5,10,15-tris(4-octadecyloxyphenyl)-20-(4-pyridyl)porphyrin. Meanwhile, with more pronounced kinks result...

Three double-decker complexes of cerium(IV) were synthesized, which commonly have a 5,10,15,20-tetrakis(4-docosyloxyphenyl)porphyrin (C22OPP) moiety as one the two tetrapyrrole rings. The three complexesCe(Pc)(C22OPP), Ce(C22OPP)2, and Ce(BPEPP)(C22OPP)are distinguished by other rings, are Pc (=phthalocyanine), C22OPP, BPEPP (=5,15-bis[4-(phenylethynyl)phenyl]porphyrin), respectively. rate inter-ring rotation Ce(BPEPP)(C22OPP) was estimated to be ∼3 s-1 in solution at room temperature. These...

Amphiphilic monomers, which were quantitatively synthesized from a dehydration reaction between glycolipid and naphthalene-boronic acids, self-assembled in organic solvents to selectively form tape-like structures (nanotape) tubular (nanotube) depending on the bond position of boron atom naphthalene ring. The nanotube has strong narrow fluorescence band attributable monomer species group, whereas nanotape weak broad at relative longer wavelength region based excimer group. Light energy...

Scanning tunneling microscopy has revealed the reorientation of one macrocyclic rings double-decker porphyrin complex [Ce(TPP-Fc)(C(22)OPP)] [TPP-Fc = 5-(4-(4-ferrocenylphenylethynyl)phenyl)-10,15,20-triphenylporphyrin; C(22)OPP 5,10,15,20-tetrakis(4-docosyloxyphenyl)porphyrin] by 90 degrees between scans when other ring is fixed on a surface. This libration was evidenced monitoring location appended ferrocene unit, which functioned as molecular beacon signaling its position.

Ein [2]Catenan als mechanischer Schalter: In dieser Verbindung umschließt ein Cyclobis(paraquat-p-phenylen)-Tetrakation einen makrocyclischen Polyether, der eine redoxaktive Tetrathiafulvalen(TTF)-Einheit und 1,5-Dioxynaphthalinring enthält. Dieser molekulare Schalter läßt sich chemisch oder elektrochemisch betätigen. Im reduzierten Zustand liegt die neutrale TTF-Einheit „innerhalb”︁, im oxidierten (TTF+/TTF2+) dagegen „längsseits”︁ des tetrakationischen Cyclophans; Wechsel zwischen...

Alkyl-chain-assisted self-assembled monolayers of pyridine-coordinated porphyrin rhodium chlorides were observed at the solid−liquid interface by scanning tunneling microscopy (STM). The resolved images a molecular level obtainable in pure solution chloride with four triacontyl groups [Rh(C30OPP)(Cl)(Py)]. In case octadecyl [Rh(C18OPP)(Cl)(Py)], STM not Rh(C18OPP)(Cl)(Py) but mixture containing and free C18OPP. On basis mixed monolayer analysis, apparent difference adsorption energy between...

The so-called slippage methodology has been employed to self-assemble novel [2]-, [3]-, and [4]-rotaxanes incorporating, respectively, one, two, three bis-p-phenylene-34-crown-10 macrocyclic components a branched 'dumbbell' component, consisting of arms containing bipyridinium units attached covalently 1,3,5-trisubstituted benzene central core each bearing at its other end substituted tetraarylmethane stopper. absorption spectra, luminescence properties, electrochemical behaviour the...

The alkyl chain length on alkyl-substituted phthalocyanines (CnOPc) dependence of their self-organized structures was examined in this study. STM results indicated that the symmetry ordered decreased as became longer, with exception C6OPc, which preferentially formed a quasi-3-fold symmetrical structure. This could be explained by fact CnOPc molecules are most likely to form densely packed structures. With CnOPc, when n = 4 10, were dependent competition between how arranged and loose...

Functional drug-delivery vehicles consisting of Ag-embedded bilayer membranes a peptidic lipid nanotube (LNT) are synthesized. The Ag–LNTs possess antimicrobial ability against E coli, contributing to the release Ag+ into aqueous culture. may be applicable delivery DNA or biotechnological drugs that usually sensitive changes in their surroundings. Detailed facts importance specialist readers published as "Supporting Information". Such documents peer-reviewed, but not copy-edited typeset....

The molecular motion of surface-immobilized double-decker phthalocyanine complexes was examined using STM. (C(8)OPc)(2)Ce (1), (C(12)OPc)(2)Ce (2), and (C(8)OPc)Ce(Pc) (3) complexes, which two ligands contained Pc nuclei, formed well-ordered self-organized structures on their own. Square-shaped top were clearly observed for 1, 2, 3 even though free space presented around the caused by mixing with template molecules. However, details shapes changed surrounding environment. environment...