Amide-Driven Secondary Building Unit Structural Transformations between Zn(II) Coordination Polymers

The behavior of coordination polymers (CPs) against external stimuli has witnessed remarkable attention, especially when the resulting CPs present reversible molecular arrays. Accordingly, CPs with these characteristics can lead to differences in their properties owing to these structural difference...

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Detalhes bibliográficos
Autores: Ejarque, Daniel, Calvet Pallàs, Maria Teresa, Font Bardia, Ma. Mercedes, Pons, Josefina
Formato: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2022
País:España
Recursos:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/208842
Acesso em linha:https://hdl.handle.net/2445/208842
Access Level:acceso abierto
Palavra-chave:Cristal·lografia
Estructura cristal·lina (Sòlids)
Química supramolecular
Crystallography
Layer structure (Solids)
Supramolecular chemistry
Descrição
Resumo:The behavior of coordination polymers (CPs) against external stimuli has witnessed remarkable attention, especially when the resulting CPs present reversible molecular arrays. Accordingly, CPs with these characteristics can lead to differences in their properties owing to these structural differences, being promising for their use as potential molecular switches with diverse applications. Herein, we have synthesized four Zn(II) CPs bearing α-acetamidocinnamic acid (HACA) and 4,4′-bipyridine (4,4′-bipy). The reaction between Zn(OAc)2·2H2O, HACA, and 4,4′-bipy yields {[Zn(ACA)2(4,4′-bipy)]·EtOH}n (1), which was used for the formation of three CPs through dissolution–recrystallization structural transformations (DRSTs): {[Zn(ACA)2(4,4′-bipy)]·2MeOH}n (2), {[Zn2(μ-ACA)2(ACA)2(4,4′-bipy)]·2H2O}n (3), and {[Zn3(μ-ACA)6(4,4′-bipy)]·0.75CHCl3}n (4). The study of the four crystal structures revealed that their secondary building units (SBUs) comprise monomeric, dimeric, and trimeric arrangements linked by 4,4′-bipy ligands. The fundamental role of the utilized solvent and/or temperature, as well as their effect on the orientation of the amide moieties driving the formation of the different SBUs is discussed. Furthermore, the reversibility and interconversion between the four CPs have been assayed. Finally, their solid-state photoluminescence has evinced that the effect of the amide moieties not only predetermine a different SBU but also lead to a different emission in 4 compared with 1–3.