The host−guest inclusion complexes of cucurbiturils with alkyl viologen have interesting architectures, chemicalproperties, and potential applications in sensors and nanotechnology. A highly hydrated triclinic crystal of cucurbit[8]uril (CB[8]) complexed by methyl hexadecyl viologen (MVC16) is characterized by the unprecedented coexistence in the crystal of three host−guest complexes with 3:2, 2:2, and 1:1 stoichiometries. In all these complexes, the hook-shaped alkyl chain of the MVC16 is hosted in the CB[8] macrocycles, while the methyl viologen moieties have various environments. In the Z-shaped 3:2 complex, a central CB[8] unit hosts two viologen heads in the cavity, while the 2:2 complex is held together by π-stacking interactions between two viologen units. In the square 2D tiling crystal packing of CB[8] macrocycles, the same site which favors the dimerization observed in the 2:2 complex is also statistically occupied by a single methyl viologen moiety of the 1:1 complex. The rational interpretation of the crystal structure represented an intriguing challenge, due to the complicated statistical disorder in the alkyl chains hosted in CB[8] units and in the methyl viologen moieties of 2:2 and 1:1 complexes. In contrast with the solution behavior dominated by the 2:1 complex, the coexistence of three host−guest complexes with 3:2, 2:2, and 1:1 ratios highlights the fundamental importance of packing effects in the crystallized supramolecular complexes. Therefore, the crystallization process has permitted us to capture different host−guest systems in a single crystal, revealing a supramolecular landscape in a single photo.

Methyl Hexadecyl Viologen Inclusion in Cucurbit[8]uril: Coexistence of Three Host–Guest Complexes with Different Stoichiometry in a Highly Hydrated Crystal / Hickey, Neal; Medagli, Barbara; Pedrini, Alessandro; Pinalli, Roberta; Dalcanale, Enrico; Geremia, Silvano. - In: CRYSTAL GROWTH & DESIGN. - ISSN 1528-7483. - 21:7(2021), pp. 3650-3655. [10.1021/acs.cgd.1c00463]

Methyl Hexadecyl Viologen Inclusion in Cucurbit[8]uril: Coexistence of Three Host–Guest Complexes with Different Stoichiometry in a Highly Hydrated Crystal

Pedrini, Alessandro;Pinalli, Roberta;Dalcanale, Enrico;
2021-01-01

Abstract

The host−guest inclusion complexes of cucurbiturils with alkyl viologen have interesting architectures, chemicalproperties, and potential applications in sensors and nanotechnology. A highly hydrated triclinic crystal of cucurbit[8]uril (CB[8]) complexed by methyl hexadecyl viologen (MVC16) is characterized by the unprecedented coexistence in the crystal of three host−guest complexes with 3:2, 2:2, and 1:1 stoichiometries. In all these complexes, the hook-shaped alkyl chain of the MVC16 is hosted in the CB[8] macrocycles, while the methyl viologen moieties have various environments. In the Z-shaped 3:2 complex, a central CB[8] unit hosts two viologen heads in the cavity, while the 2:2 complex is held together by π-stacking interactions between two viologen units. In the square 2D tiling crystal packing of CB[8] macrocycles, the same site which favors the dimerization observed in the 2:2 complex is also statistically occupied by a single methyl viologen moiety of the 1:1 complex. The rational interpretation of the crystal structure represented an intriguing challenge, due to the complicated statistical disorder in the alkyl chains hosted in CB[8] units and in the methyl viologen moieties of 2:2 and 1:1 complexes. In contrast with the solution behavior dominated by the 2:1 complex, the coexistence of three host−guest complexes with 3:2, 2:2, and 1:1 ratios highlights the fundamental importance of packing effects in the crystallized supramolecular complexes. Therefore, the crystallization process has permitted us to capture different host−guest systems in a single crystal, revealing a supramolecular landscape in a single photo.
2021
Methyl Hexadecyl Viologen Inclusion in Cucurbit[8]uril: Coexistence of Three Host–Guest Complexes with Different Stoichiometry in a Highly Hydrated Crystal / Hickey, Neal; Medagli, Barbara; Pedrini, Alessandro; Pinalli, Roberta; Dalcanale, Enrico; Geremia, Silvano. - In: CRYSTAL GROWTH & DESIGN. - ISSN 1528-7483. - 21:7(2021), pp. 3650-3655. [10.1021/acs.cgd.1c00463]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2893458
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