title: Molecular Basis for the Recognition of Higher Fullerenes into Ureidopyrimidinone-Cyclotriveratrylene Self-Assembled Capsules.
abstract: Fullerenes C60 , C70 , and C84 may be readily encaged within a hydrogen-bonded dimeric capsule, based on two concave cyclotriveratrylene (CTV) scaffolds, each containing three self-complementary 2-ureido-4-[1H]-pyrimidinone (UPy) subunits. NMR spectroscopy and circular dichroism studies, complemented by dispersion-corrected DFT calculations, are reported with the aim of characterizing such capsule-fullerene complexes both structurally and energetically. Six fullerenes are considered: in agreement with experiments, calculations find that encapsulation is most favorable for C84 (on a par with C90 ), and follows the trend C60 <C70 <C76 <C78 <C84 ≈C90 . As also found by NMR spectroscopy, the most stable capsules are formed by monomers of identical stereochemistry with UPy and the OMe groups of CTV in a mutual anti orientation and UPy-CTV ethylene linkers within the capsular surface plane. Up to C78 , encapsulation is favored by increasing host-guest contacts, but the trend is thereafter increasingly inhibited by growing capsule strain.
authors.affiliation: Catalan Institute of Chemical Research (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain.
authors.forename: Elisa
authors.initials: E
authors.lastname: Huerta
authors.affiliation: Catalan Institute of Chemical Research (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain.
authors.forename: Stefano Artin
authors.identifier: http://orcid.org/0000-0003-0122-8499
authors.initials: SA
authors.lastname: Serapian
authors.affiliation: Catalan Institute of Chemical Research (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Santos
authors.affiliation: Catalan Institute of Chemical Research (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Cequier
authors.affiliation: Catalan Institute of Chemical Research (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain. cbo@iciq.es.
authors.forename: Carles
authors.identifier: http://orcid.org/0000-0001-9581-2922
authors.initials: C
authors.lastname: Bo
authors.affiliation: Catalan Institute of Chemical Research (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain. jmendoza@iciq.es.
authors.forename: Javier
authors.initials: J
authors.lastname: de Mendoza
keywords: NMR spectroscopy; circular dichroism; density functional calculations; fullerenes; host-guest systems