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Titolo:
Photochemical- and pH-switching properties of a new photoelastic ligand based upon azobenzene. Basicity and anion binding
Autore:
Bencini, A; Bianchi, A; Giorgi, C; Romagnoli, E; Lodeiro, C; Saint-Maurice, A; Pina, F; Valtancoli, B;
Indirizzi:
Univ Florence, Dept Chem, I-50144 Florence, Italy Univ Florence FlorenceItaly I-50144 Dept Chem, I-50144 Florence, Italy Univ Nova Lisboa, Fac Ciencias & Tecnol, Ctr Quim Fina & Biotecnol, Dept Quim, P-2825 Monte De Caparica, Portugal Univ Nova Lisboa Monte De Caparica Portugal P-2825 De Caparica, Portugal
Titolo Testata:
SUPRAMOLECULAR CHEMISTRY
fascicolo: 2, volume: 13, anno: 2001,
pagine: 277 - 285
SICI:
1061-0278(2001)13:2<277:PAPPOA>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTORESPONSIVE CROWN ETHERS; ION-TRANSPORT; BIS(CROWN ETHER); PHOTOCONTROL; EXTRACTION;
Keywords:
photoelastic ligands; chemical switches; macrocycles; anion coordination;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
24
Recensione:
Indirizzi per estratti:
Indirizzo: Bianchi, A Univ Florence, Dept Chem, Via Maragliano 75-77, I-50144 Florence, Italy Univ Florence Via Maragliano 75-77 Florence Italy I-50144 taly
Citazione:
A. Bencini et al., "Photochemical- and pH-switching properties of a new photoelastic ligand based upon azobenzene. Basicity and anion binding", SUPRAMOL CH, 13(2), 2001, pp. 277-285

Abstract

The synthesis of a new cylindrical macrotricyclic ligand (L) based upon two 1,4,7,13-tetramethyl-1,4,7, 10,13,16-hexaazacyclooctadecane rings connected via two azobenzene pillars is described. The ligands displays photoelastic properties: light absorption at 366 nm produces trans --> cis isomerization of the azobenzene moieties with formation of trans-cis (LE-Z) and cis-cis (LZ-Z) isomers. Recovery of the thermodynamically more stable trans-trans (LE-E) isomer can be obtained by thermal back-isomerization or visible light (430 nm) absorption. The isomeric composition of L solution depends upon pH: for pH < 5.5 the LE-E form is the unique species in solution, while increasing amounts of Z species are formed at increasing pH. The protonationconstants of LE-E have been determined in 0.1 mol dm(-3) Me4NNO3 solution at 298.1 +/- 0.1 K. The protonated species of L form stable inclusion complexes with anionic species such as [Co(CN)(6)](3-).

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/10/20 alle ore 15:57:04