The fabrication of porous architectures for the confinement of gases and polymer chains to pores is a challenging research area. The matrices range from fully-organic and metal-organic frameworks to porous molecular crystals of synthetic and biological origin, such as dipeptides.[1] We were mostly intrigued in comparing the matrices depending on the nature of the interactions, pore shape, surface area and pore capacity. Like gases, flexible polymer chains can diffuse inside the galleries undergoing severe steric requirements which tune their conformations, dynamics and properties. Fast-1H, 19F and 2D hetero-correlated MAS NMR spectroscopies played a key role in determining the host-guest interactions at the interfaces and the relationships between the components. A few case studies will be highlighted. A peculiar kind of porous crystalline solid derives from the use of hard and soft interactions in a hierarchical construction. Primary supramolecular toroidal structures are formed by robust metal-organic bonds: they can self-assemble four-by-four into the shape of Platonic solids, held together by van der Waals and coulombic interactions.[2] Anions play a major role in modulating the architectures. The 3D crystalline structures are permanently porous and able to entrap reversibly vapors and gases. In a further example, 1,3-butadiene vapors could be separated from other C4 hydrocarbon by a MOF matrix [3], which provides structural flexibility and unique guest-responsive accommodation. Regarding the relevant issue of manipulating and transforming polymer chains in a confined environment, we varied the conducting properties of polyacrylonitrile chains by thermal transformation into graphitized nanofibers.[4] Moreover, isolation of single polysilane chains increased the rate of carrier mobility in comparison with that in the bulk state due to the elimination of the slow interchain hole-hopping.[5] The main chain conformation of polysilane could be controlled by changing the nanochannel cross-section, as evidenced by Raman spectroscopy and solid-state NMR.
Sozzani, P., Perego, J., Piga, D., Asnaghi, D., Bassanetti, I., Bracco, S. (2017). Absorptive Organic and Hybrid Materials for Gases and Polymers. In Abstract Book (pp.69-69).
Absorptive Organic and Hybrid Materials for Gases and Polymers
Sozzani, P
Membro del Collaboration Group
;Perego, JMembro del Collaboration Group
;Piga, D;Asnaghi, DMembro del Collaboration Group
;Bassanetti, IMembro del Collaboration Group
;Bracco, SMembro del Collaboration Group
2017
Abstract
The fabrication of porous architectures for the confinement of gases and polymer chains to pores is a challenging research area. The matrices range from fully-organic and metal-organic frameworks to porous molecular crystals of synthetic and biological origin, such as dipeptides.[1] We were mostly intrigued in comparing the matrices depending on the nature of the interactions, pore shape, surface area and pore capacity. Like gases, flexible polymer chains can diffuse inside the galleries undergoing severe steric requirements which tune their conformations, dynamics and properties. Fast-1H, 19F and 2D hetero-correlated MAS NMR spectroscopies played a key role in determining the host-guest interactions at the interfaces and the relationships between the components. A few case studies will be highlighted. A peculiar kind of porous crystalline solid derives from the use of hard and soft interactions in a hierarchical construction. Primary supramolecular toroidal structures are formed by robust metal-organic bonds: they can self-assemble four-by-four into the shape of Platonic solids, held together by van der Waals and coulombic interactions.[2] Anions play a major role in modulating the architectures. The 3D crystalline structures are permanently porous and able to entrap reversibly vapors and gases. In a further example, 1,3-butadiene vapors could be separated from other C4 hydrocarbon by a MOF matrix [3], which provides structural flexibility and unique guest-responsive accommodation. Regarding the relevant issue of manipulating and transforming polymer chains in a confined environment, we varied the conducting properties of polyacrylonitrile chains by thermal transformation into graphitized nanofibers.[4] Moreover, isolation of single polysilane chains increased the rate of carrier mobility in comparison with that in the bulk state due to the elimination of the slow interchain hole-hopping.[5] The main chain conformation of polysilane could be controlled by changing the nanochannel cross-section, as evidenced by Raman spectroscopy and solid-state NMR.
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