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Titolo:
AGGREGATION OF SELF-ASSEMBLING BRANCHED [N]ROTAXANES
Autore:
AMABILINO DB; ASAKAWA M; ASHTON PR; BALLARDINI R; BALZANI V; BELOHRADSKY M; CREDI A; HIGUCHI M; RAYMO FM; SHIMIZU T; STODDART JF; VENTURI M; YASE K;
Indirizzi:
UNIV BIRMINGHAM,SCH CHEM,POB 363 BIRMINGHAM B15 2TT W MIDLANDS ENGLAND UNIV BIRMINGHAM,SCH CHEM BIRMINGHAM B15 2TT W MIDLANDS ENGLAND NATL INST MAT & CHEM RES IBARAKI OSAKA 305 JAPAN CNR,IST FRAE I-40129 BOLOGNA ITALY UNIV BOLOGNA,DIPARTIMENTO CHIM G CIAMICIAN I-40126 BOLOGNA ITALY
Titolo Testata:
New journal of chemistry
fascicolo: 9, volume: 22, anno: 1998,
pagine: 959 - 972
SICI:
1144-0546(1998)22:9<959:AOSB[>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
STARBURST CASCADE DENDRIMERS; FUNDAMENTAL BUILDING-BLOCKS; NANOSCOPIC CHEMISTRY SET; HYDROGEN-BOND PATTERNS; SUPRAMOLECULAR CHEMISTRY; MOLECULAR RECOGNITION; CHARGE-TRANSFER; STACKING INTERACTIONS; ELECTRON-TRANSFER; TRANSITION-METAL;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
110
Recensione:
Indirizzi per estratti:
Citazione:
D.B. Amabilino et al., "AGGREGATION OF SELF-ASSEMBLING BRANCHED [N]ROTAXANES", New journal of chemistry, 22(9), 1998, pp. 959-972

Abstract

The so-called slippage methodology has been employed to self-assemblenovel [2]-, [3]-, and [4]-rotaxanes incorporating, respectively, one,two, and three bis-p-phenylene-34-crown-10 macrocyclic components anda branched 'dumbbell' component, consisting of three arms containing bipyridinium units attached covalently to a 1,3,5-trisubstituted benzene central core and each bearing at its other end a substituted tetraarylmethane stopper. The absorption spectra, luminescence properties, and electrochemical behaviour of the branched component and its [2]- [3]-, and [4]-rotaxanes have been investigated and discussed on the basis of the properties of their chromophoric and electroactive units. Charge- and energy-transfer processes between specific chromophoric unitsand the correlations between the unusual redox patterns of the various compounds have been evidenced and interpreted. The H-1-NMR spectroscopic investigation of the 'free' triply-branched hexacationic core, containing three bipyridinium units, one in each arm and terminated by bulky hydrophobic tetraarylmethane-based stoppers revealed, in chloroform solution, the formation of aggregates-a phenomenon which has been modeled using force field calculations. In addition, the formation of agel was observed after the slow liquid-liquid diffusion of hexane into a chloroform solution of the triply-branched compound. Field-emission scanning electron microscopic investigation of this gel revealed thepresence of domains of regular size. Surface-pressure-area measurements demonstrated the formation of stable monolayers by the 'free' backbone and the rotaxanes at an air-water interface: two distinct aggregates are formed by each compound. Interestingly, for the rotaxanes, the measured limiting area per molecule of both aggregates increases with the number of macrocyclic components which are incorporated within therotaxane molecule. Atomic force microscopic analyses of the monolayers transferred onto mica revealed significant differences in their shapes when the two distinct aggregates formed by the same compound at different pressures were compared. In particular, the section analyses ofthe monolayers showed nanosized domains possessing diameters ranging from approximately 10 to 56 nm.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/01/20 alle ore 14:43:32