Controlling Multivalent Interactions in Triply-Threaded Two-Component Superbundles
We have investigated the 1H NMR spectra, the absorption spectra, the fluorescence spectra and decays, and the electrochemical properties of i) a tritopic receptor in which three benzo[24]crown‐8 macrorings are fused onto a triphenylene core, ii) a trifurcated trication wherein three dibenzylammonium...
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| creator | Balzani, Vincenzo Clemente-León, Miguel Credi, Alberto Lowe, James N. Badjić, Jovica D. Stoddart, J. Fraser Williams, David J. |
| description | We have investigated the 1H NMR spectra, the absorption spectra, the fluorescence spectra and decays, and the electrochemical properties of i) a tritopic receptor in which three benzo[24]crown‐8 macrorings are fused onto a triphenylene core, ii) a trifurcated trication wherein three dibenzylammonium ions are linked 1,3,5 to a central benzenoid core, and iii) their 1:1 adduct which constitutes a triply‐threaded, two‐component supramolecular bundle. X‐Ray crystallography has established the precise geometry of this paucivalent recognition motif in the solid state. In addition to [N+‐H⋅⋅⋅O] hydrogen bonding and [C‐H⋅⋅⋅O] interactions between the NH2+ centers on the three dibenzylammonium ion containing arms of the trication and the three crown ether rings in the tritopic receptor, there is a stabilizing [π⋅⋅⋅π] stacking interaction between the two aromatic cores. Mass spectrometry and 1H NMR spectroscopy have confirmed the integrity of the 1:1 adduct beyond the solid state, provided the solvents are relatively apolar (e.g., chloroform and acetonitrile). The intense fluorescence emissions of the two recognition components are quenched upon association with the concomitant appearance of a lower energy, broad fluorescence band originating from the π–π stacking in the 1:1 adduct of the aromatic cores in the two matching components. Titration experiments, including Job plots, establish the 1:1 stoichiometry of the adduct, an observation which is also confirmed by electrochemical experiments. The electrochemical results show that, both in the tritopic receptor and in the superbundle itself, the first oxidation process is associated with the hexaalkoxytriphenylene core. The successive oxidation processes of the peripheral dioxybenzene units are affected by charge‐transfer interactions in the tritopic receptor, whereas, in the superbundle, such units are not interacting. In acetonitrile solution, dethreading/rethreading of the 1:1 adduct can be controlled quantitatively by addition of base and acid. Dethreading and rethreading is also observed by 1H NMR spectroscopy when dimethylsulfoxide is added to a solution of the 1:1 adduct in equal volumes of acetonitrile and chloroform. A trifurcated trication where methyl groups are located on the para positions of the three dibenzylammonium ions, which are linked 1,3,5 to the neutral benzenoid core, has been employed to demonstrate that dethreading of the 1:1 adduct involves doubly‐threaded and singly‐threaded species, that |
| doi_str_mv | 10.1002/chem.200304979 |
| format | Article |
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Sono stati studiati gli spettri 1H NMR, gli spettri di assorbimento elettronico, gli spettri ed i decadimenti di fluorescenza e le proprietà elettrochimiche di i) un recettore tritopico formato da tre macrocicli benzo[24]corona‐8 costruiti su un gruppo trifenilene centrale, ii) un tricatione ramificato in cui tre ioni dibenzilammonio sono legati ad un'unità benzenica centrale in posizione 1,3,5 e iii) il loro addotto 1:1. Quest'ultimo costituisce una sorta di “fascio” supramolecolare, in cui ciascun ramo del componente tricationico è infilato in un macrociclo del recettore tritopico. L'analisi cristallografica ai raggi X ha permesso di stabilire la geometria dell'addotto allo stato solido e di evidenziare le interazioni fra i suoi componenti. Oltre a legami a idrogeno [N+‐H⋅⋅⋅O] e [C‐H⋅⋅⋅O] tra gli ioni dibenzilammonio di un componente e gli eteri corona dell'altro, si osservano interazioni di stacking [π⋅⋅⋅π] tra le due unità aromatiche centrali. L'addotto 1:1 è stabile anche in soluzione, come dimostrato da esperimenti di spettrometria di massa e di spettroscopia 1H NMR, purché in solventi relativamente poco polari come il cloroformio o l'acetonitrile. L'intensa fluorescenza dei due componenti molecolari viene spenta in seguito alla loro associazione, con la concomitante comparsa di una banda di fluorescenza larga e a bassa energia dovuta alle interazioni [π⋅⋅⋅π] tra le due unità aromatiche centrali nell′addotto. La stechiometria 1:1 dell'addotto è confermata da titolazioni, Job plot ed esperimenti elettrochimici. I risultati di questi ultimi esperimenti mostrano che il primo processo di ossidazione osservato sia nel recettore tritopico che nell'addotto è attribuibile all'unità centrale esaossitrifenilene. I successivi processi di ossidazione delle unità diossibenzene periferiche nel recettore tritopico sono influenzati da interazioni di trasferimento di carica, mentre tali unità non interagiscono tra loro quando si trovano nell'addotto. In acetonitrile l'addotto 1:1 può essere sfilato e reinfilato in maniera quantitativa e controllata mediante l'aggiunta di acido e di base. I processi di sfilamento e reinfilamento si osservano anche aggiungendo dimetilsolfossido ad una soluzione dell'addotto in acetonitrile/cloroformio 50:50 (v/v), attraverso la spettroscopia 1H NMR. Utilizzando un tricatione ramificato in cui si sono introdotti gruppi metilici in posizione para nelle tre unità dibenzilammonio, è stato possibile dimostrare che lo sfilamento dell'addotto 1:1 coinvolge specie doppiamente e singolarmente infilate. In altre parole, l'addotto si disassembla secondo una sequenza logica che passa attraverso specie intermedie stabili. Questo sistema di riconoscimento molecolare costituisce un raffinato esempio di architettura supramolecolare basata su interazioni che cooperano tra loro e che possono essere attivate e disattivate mediante stimoli chimici.
Two perfectly matching molecular pieces, each with trigonal symmetry, fit together like a three‐pin plug into a powersocket (see scheme). The triply‐interpenetrating relative geometry associated with this three‐point, hydrogen‐bond driven recognition is aided and abetted by π–π stacking interactions involving the two aromatic platforms. The cooperativity that is part and parcel of this recognition site is expressed multivalently in a chelate‐like manner, leading to an extremely strong 1:1 complex in apolar solvents that do not compete for the hydrogen‐bond donors and acceptors situated in the plug‐and‐socket, respectively. The resulting superbundle falls apart in strong base and can be reassembled by the addition of acid, that is, the recognition motif can be subjected to direct chemomechanical control, affording an actuator of nanoscale dimensions.</description><identifier>ISSN: 0947-6539</identifier><identifier>EISSN: 1521-3765</identifier><identifier>DOI: 10.1002/chem.200304979</identifier><identifier>PMID: 14613145</identifier><language>eng</language><publisher>Weinheim: WILEY-VCH Verlag</publisher><subject>hydrogen bonds ; luminescence ; molecular machines ; molecular recognition ; self-assembly</subject><ispartof>Chemistry : a European journal, 2003-11, Vol.9 (21), p.5348-5360</ispartof><rights>Copyright © 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim</rights><lds50>peer_reviewed</lds50><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c3489-b48e6a9cee750d1fe031387c1312a29bdd0e756f9a21de8bcbcfffbb0d968e543</citedby><cites>FETCH-LOGICAL-c3489-b48e6a9cee750d1fe031387c1312a29bdd0e756f9a21de8bcbcfffbb0d968e543</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktohtml>$$Uhttps://onlinelibrary.wiley.com/doi/full/10.1002%2Fchem.200304979$$EHTML$$P50$$Gwiley$$H</linktohtml><link.rule.ids>315,781,785,1418,27929,27930,45580</link.rule.ids><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/14613145$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Balzani, Vincenzo</creatorcontrib><creatorcontrib>Clemente-León, Miguel</creatorcontrib><creatorcontrib>Credi, Alberto</creatorcontrib><creatorcontrib>Lowe, James N.</creatorcontrib><creatorcontrib>Badjić, Jovica D.</creatorcontrib><creatorcontrib>Stoddart, J. Fraser</creatorcontrib><creatorcontrib>Williams, David J.</creatorcontrib><title>Controlling Multivalent Interactions in Triply-Threaded Two-Component Superbundles</title><title>Chemistry : a European journal</title><addtitle>Chemistry - A European Journal</addtitle><description>We have investigated the 1H NMR spectra, the absorption spectra, the fluorescence spectra and decays, and the electrochemical properties of i) a tritopic receptor in which three benzo[24]crown‐8 macrorings are fused onto a triphenylene core, ii) a trifurcated trication wherein three dibenzylammonium ions are linked 1,3,5 to a central benzenoid core, and iii) their 1:1 adduct which constitutes a triply‐threaded, two‐component supramolecular bundle. X‐Ray crystallography has established the precise geometry of this paucivalent recognition motif in the solid state. In addition to [N+‐H⋅⋅⋅O] hydrogen bonding and [C‐H⋅⋅⋅O] interactions between the NH2+ centers on the three dibenzylammonium ion containing arms of the trication and the three crown ether rings in the tritopic receptor, there is a stabilizing [π⋅⋅⋅π] stacking interaction between the two aromatic cores. Mass spectrometry and 1H NMR spectroscopy have confirmed the integrity of the 1:1 adduct beyond the solid state, provided the solvents are relatively apolar (e.g., chloroform and acetonitrile). The intense fluorescence emissions of the two recognition components are quenched upon association with the concomitant appearance of a lower energy, broad fluorescence band originating from the π–π stacking in the 1:1 adduct of the aromatic cores in the two matching components. Titration experiments, including Job plots, establish the 1:1 stoichiometry of the adduct, an observation which is also confirmed by electrochemical experiments. The electrochemical results show that, both in the tritopic receptor and in the superbundle itself, the first oxidation process is associated with the hexaalkoxytriphenylene core. The successive oxidation processes of the peripheral dioxybenzene units are affected by charge‐transfer interactions in the tritopic receptor, whereas, in the superbundle, such units are not interacting. In acetonitrile solution, dethreading/rethreading of the 1:1 adduct can be controlled quantitatively by addition of base and acid. Dethreading and rethreading is also observed by 1H NMR spectroscopy when dimethylsulfoxide is added to a solution of the 1:1 adduct in equal volumes of acetonitrile and chloroform. A trifurcated trication where methyl groups are located on the para positions of the three dibenzylammonium ions, which are linked 1,3,5 to the neutral benzenoid core, has been employed to demonstrate that dethreading of the 1:1 adduct involves doubly‐threaded and singly‐threaded species, that is, the paucivalent site is dismembered in a sequence of logical steps involving stable intermediates. This molecular recognition system is a rare example of a supramolecular entity based on a cooperative binding motif that can be switched on and off by chemical means.
Sono stati studiati gli spettri 1H NMR, gli spettri di assorbimento elettronico, gli spettri ed i decadimenti di fluorescenza e le proprietà elettrochimiche di i) un recettore tritopico formato da tre macrocicli benzo[24]corona‐8 costruiti su un gruppo trifenilene centrale, ii) un tricatione ramificato in cui tre ioni dibenzilammonio sono legati ad un'unità benzenica centrale in posizione 1,3,5 e iii) il loro addotto 1:1. Quest'ultimo costituisce una sorta di “fascio” supramolecolare, in cui ciascun ramo del componente tricationico è infilato in un macrociclo del recettore tritopico. L'analisi cristallografica ai raggi X ha permesso di stabilire la geometria dell'addotto allo stato solido e di evidenziare le interazioni fra i suoi componenti. Oltre a legami a idrogeno [N+‐H⋅⋅⋅O] e [C‐H⋅⋅⋅O] tra gli ioni dibenzilammonio di un componente e gli eteri corona dell'altro, si osservano interazioni di stacking [π⋅⋅⋅π] tra le due unità aromatiche centrali. L'addotto 1:1 è stabile anche in soluzione, come dimostrato da esperimenti di spettrometria di massa e di spettroscopia 1H NMR, purché in solventi relativamente poco polari come il cloroformio o l'acetonitrile. L'intensa fluorescenza dei due componenti molecolari viene spenta in seguito alla loro associazione, con la concomitante comparsa di una banda di fluorescenza larga e a bassa energia dovuta alle interazioni [π⋅⋅⋅π] tra le due unità aromatiche centrali nell′addotto. La stechiometria 1:1 dell'addotto è confermata da titolazioni, Job plot ed esperimenti elettrochimici. I risultati di questi ultimi esperimenti mostrano che il primo processo di ossidazione osservato sia nel recettore tritopico che nell'addotto è attribuibile all'unità centrale esaossitrifenilene. I successivi processi di ossidazione delle unità diossibenzene periferiche nel recettore tritopico sono influenzati da interazioni di trasferimento di carica, mentre tali unità non interagiscono tra loro quando si trovano nell'addotto. In acetonitrile l'addotto 1:1 può essere sfilato e reinfilato in maniera quantitativa e controllata mediante l'aggiunta di acido e di base. I processi di sfilamento e reinfilamento si osservano anche aggiungendo dimetilsolfossido ad una soluzione dell'addotto in acetonitrile/cloroformio 50:50 (v/v), attraverso la spettroscopia 1H NMR. Utilizzando un tricatione ramificato in cui si sono introdotti gruppi metilici in posizione para nelle tre unità dibenzilammonio, è stato possibile dimostrare che lo sfilamento dell'addotto 1:1 coinvolge specie doppiamente e singolarmente infilate. In altre parole, l'addotto si disassembla secondo una sequenza logica che passa attraverso specie intermedie stabili. Questo sistema di riconoscimento molecolare costituisce un raffinato esempio di architettura supramolecolare basata su interazioni che cooperano tra loro e che possono essere attivate e disattivate mediante stimoli chimici.
Two perfectly matching molecular pieces, each with trigonal symmetry, fit together like a three‐pin plug into a powersocket (see scheme). The triply‐interpenetrating relative geometry associated with this three‐point, hydrogen‐bond driven recognition is aided and abetted by π–π stacking interactions involving the two aromatic platforms. The cooperativity that is part and parcel of this recognition site is expressed multivalently in a chelate‐like manner, leading to an extremely strong 1:1 complex in apolar solvents that do not compete for the hydrogen‐bond donors and acceptors situated in the plug‐and‐socket, respectively. The resulting superbundle falls apart in strong base and can be reassembled by the addition of acid, that is, the recognition motif can be subjected to direct chemomechanical control, affording an actuator of nanoscale dimensions.</description><subject>hydrogen bonds</subject><subject>luminescence</subject><subject>molecular machines</subject><subject>molecular recognition</subject><subject>self-assembly</subject><issn>0947-6539</issn><issn>1521-3765</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2003</creationdate><recordtype>article</recordtype><recordid>eNqFkE9PwjAYhxujEUSvHs2-QLFd969HnQhEUKNTEi9Nu76T6diWbhP59o6MoDdPPbzP80vzIHROyZASYl_GS1gNbUIYcbjPD1CfujbFzPfcQ9Qn3PGx5zLeQydV9UEI4R5jx6hHHY8y6rh99BQWeW2KLEvzd2veZHX6JTPIa2ua12BkXKdFXllpbkUmLbMNjpYGpAZtResCh8WqLPIt_dyUYFST6wyqU3SUyKyCs907QC-3oyic4NnDeBpezXDMnIBj5QTgSR4D-C7RNAHCKAv8uP2YLW2utCbtxUu4tKmGQMUqTpJEKaK5F4DrsAEadruxKarKQCJKk66k2QhKxDaO2MYR-zitcNEJZaNWoH_xXY0W4B2wTjPY_DMnwslo_nccd25a1fC9d6X5FJ7PfFcs7sfi-nUyXtw8vok79gO-PYLe</recordid><startdate>20031107</startdate><enddate>20031107</enddate><creator>Balzani, Vincenzo</creator><creator>Clemente-León, Miguel</creator><creator>Credi, Alberto</creator><creator>Lowe, James N.</creator><creator>Badjić, Jovica D.</creator><creator>Stoddart, J. Fraser</creator><creator>Williams, David J.</creator><general>WILEY-VCH Verlag</general><general>WILEY‐VCH Verlag</general><scope>BSCLL</scope><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope></search><sort><creationdate>20031107</creationdate><title>Controlling Multivalent Interactions in Triply-Threaded Two-Component Superbundles</title><author>Balzani, Vincenzo ; Clemente-León, Miguel ; Credi, Alberto ; Lowe, James N. ; Badjić, Jovica D. ; Stoddart, J. Fraser ; Williams, David J.</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c3489-b48e6a9cee750d1fe031387c1312a29bdd0e756f9a21de8bcbcfffbb0d968e543</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2003</creationdate><topic>hydrogen bonds</topic><topic>luminescence</topic><topic>molecular machines</topic><topic>molecular recognition</topic><topic>self-assembly</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Balzani, Vincenzo</creatorcontrib><creatorcontrib>Clemente-León, Miguel</creatorcontrib><creatorcontrib>Credi, Alberto</creatorcontrib><creatorcontrib>Lowe, James N.</creatorcontrib><creatorcontrib>Badjić, Jovica D.</creatorcontrib><creatorcontrib>Stoddart, J. Fraser</creatorcontrib><creatorcontrib>Williams, David J.</creatorcontrib><collection>Istex</collection><collection>PubMed</collection><collection>CrossRef</collection><jtitle>Chemistry : a European journal</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Balzani, Vincenzo</au><au>Clemente-León, Miguel</au><au>Credi, Alberto</au><au>Lowe, James N.</au><au>Badjić, Jovica D.</au><au>Stoddart, J. Fraser</au><au>Williams, David J.</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Controlling Multivalent Interactions in Triply-Threaded Two-Component Superbundles</atitle><jtitle>Chemistry : a European journal</jtitle><addtitle>Chemistry - A European Journal</addtitle><date>2003-11-07</date><risdate>2003</risdate><volume>9</volume><issue>21</issue><spage>5348</spage><epage>5360</epage><pages>5348-5360</pages><issn>0947-6539</issn><eissn>1521-3765</eissn><abstract>We have investigated the 1H NMR spectra, the absorption spectra, the fluorescence spectra and decays, and the electrochemical properties of i) a tritopic receptor in which three benzo[24]crown‐8 macrorings are fused onto a triphenylene core, ii) a trifurcated trication wherein three dibenzylammonium ions are linked 1,3,5 to a central benzenoid core, and iii) their 1:1 adduct which constitutes a triply‐threaded, two‐component supramolecular bundle. X‐Ray crystallography has established the precise geometry of this paucivalent recognition motif in the solid state. In addition to [N+‐H⋅⋅⋅O] hydrogen bonding and [C‐H⋅⋅⋅O] interactions between the NH2+ centers on the three dibenzylammonium ion containing arms of the trication and the three crown ether rings in the tritopic receptor, there is a stabilizing [π⋅⋅⋅π] stacking interaction between the two aromatic cores. Mass spectrometry and 1H NMR spectroscopy have confirmed the integrity of the 1:1 adduct beyond the solid state, provided the solvents are relatively apolar (e.g., chloroform and acetonitrile). The intense fluorescence emissions of the two recognition components are quenched upon association with the concomitant appearance of a lower energy, broad fluorescence band originating from the π–π stacking in the 1:1 adduct of the aromatic cores in the two matching components. Titration experiments, including Job plots, establish the 1:1 stoichiometry of the adduct, an observation which is also confirmed by electrochemical experiments. The electrochemical results show that, both in the tritopic receptor and in the superbundle itself, the first oxidation process is associated with the hexaalkoxytriphenylene core. The successive oxidation processes of the peripheral dioxybenzene units are affected by charge‐transfer interactions in the tritopic receptor, whereas, in the superbundle, such units are not interacting. In acetonitrile solution, dethreading/rethreading of the 1:1 adduct can be controlled quantitatively by addition of base and acid. Dethreading and rethreading is also observed by 1H NMR spectroscopy when dimethylsulfoxide is added to a solution of the 1:1 adduct in equal volumes of acetonitrile and chloroform. A trifurcated trication where methyl groups are located on the para positions of the three dibenzylammonium ions, which are linked 1,3,5 to the neutral benzenoid core, has been employed to demonstrate that dethreading of the 1:1 adduct involves doubly‐threaded and singly‐threaded species, that is, the paucivalent site is dismembered in a sequence of logical steps involving stable intermediates. This molecular recognition system is a rare example of a supramolecular entity based on a cooperative binding motif that can be switched on and off by chemical means.
Sono stati studiati gli spettri 1H NMR, gli spettri di assorbimento elettronico, gli spettri ed i decadimenti di fluorescenza e le proprietà elettrochimiche di i) un recettore tritopico formato da tre macrocicli benzo[24]corona‐8 costruiti su un gruppo trifenilene centrale, ii) un tricatione ramificato in cui tre ioni dibenzilammonio sono legati ad un'unità benzenica centrale in posizione 1,3,5 e iii) il loro addotto 1:1. Quest'ultimo costituisce una sorta di “fascio” supramolecolare, in cui ciascun ramo del componente tricationico è infilato in un macrociclo del recettore tritopico. L'analisi cristallografica ai raggi X ha permesso di stabilire la geometria dell'addotto allo stato solido e di evidenziare le interazioni fra i suoi componenti. Oltre a legami a idrogeno [N+‐H⋅⋅⋅O] e [C‐H⋅⋅⋅O] tra gli ioni dibenzilammonio di un componente e gli eteri corona dell'altro, si osservano interazioni di stacking [π⋅⋅⋅π] tra le due unità aromatiche centrali. L'addotto 1:1 è stabile anche in soluzione, come dimostrato da esperimenti di spettrometria di massa e di spettroscopia 1H NMR, purché in solventi relativamente poco polari come il cloroformio o l'acetonitrile. L'intensa fluorescenza dei due componenti molecolari viene spenta in seguito alla loro associazione, con la concomitante comparsa di una banda di fluorescenza larga e a bassa energia dovuta alle interazioni [π⋅⋅⋅π] tra le due unità aromatiche centrali nell′addotto. La stechiometria 1:1 dell'addotto è confermata da titolazioni, Job plot ed esperimenti elettrochimici. I risultati di questi ultimi esperimenti mostrano che il primo processo di ossidazione osservato sia nel recettore tritopico che nell'addotto è attribuibile all'unità centrale esaossitrifenilene. I successivi processi di ossidazione delle unità diossibenzene periferiche nel recettore tritopico sono influenzati da interazioni di trasferimento di carica, mentre tali unità non interagiscono tra loro quando si trovano nell'addotto. In acetonitrile l'addotto 1:1 può essere sfilato e reinfilato in maniera quantitativa e controllata mediante l'aggiunta di acido e di base. I processi di sfilamento e reinfilamento si osservano anche aggiungendo dimetilsolfossido ad una soluzione dell'addotto in acetonitrile/cloroformio 50:50 (v/v), attraverso la spettroscopia 1H NMR. Utilizzando un tricatione ramificato in cui si sono introdotti gruppi metilici in posizione para nelle tre unità dibenzilammonio, è stato possibile dimostrare che lo sfilamento dell'addotto 1:1 coinvolge specie doppiamente e singolarmente infilate. In altre parole, l'addotto si disassembla secondo una sequenza logica che passa attraverso specie intermedie stabili. Questo sistema di riconoscimento molecolare costituisce un raffinato esempio di architettura supramolecolare basata su interazioni che cooperano tra loro e che possono essere attivate e disattivate mediante stimoli chimici.
Two perfectly matching molecular pieces, each with trigonal symmetry, fit together like a three‐pin plug into a powersocket (see scheme). The triply‐interpenetrating relative geometry associated with this three‐point, hydrogen‐bond driven recognition is aided and abetted by π–π stacking interactions involving the two aromatic platforms. The cooperativity that is part and parcel of this recognition site is expressed multivalently in a chelate‐like manner, leading to an extremely strong 1:1 complex in apolar solvents that do not compete for the hydrogen‐bond donors and acceptors situated in the plug‐and‐socket, respectively. The resulting superbundle falls apart in strong base and can be reassembled by the addition of acid, that is, the recognition motif can be subjected to direct chemomechanical control, affording an actuator of nanoscale dimensions.</abstract><cop>Weinheim</cop><pub>WILEY-VCH Verlag</pub><pmid>14613145</pmid><doi>10.1002/chem.200304979</doi><tpages>13</tpages></addata></record> |
| fulltext | fulltext |
| identifier | ISSN: 0947-6539 |
| ispartof | Chemistry : a European journal, 2003-11, Vol.9 (21), p.5348-5360 |
| issn | 0947-6539 1521-3765 |
| language | eng |
| recordid | cdi_crossref_primary_10_1002_chem_200304979 |
| source | Access via Wiley Online Library |
| subjects | hydrogen bonds luminescence molecular machines molecular recognition self-assembly |
| title | Controlling Multivalent Interactions in Triply-Threaded Two-Component Superbundles |
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