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Structural, energetic, and dynamic insights into the abnormal xylene separation behavior of hierarchical porous crystal.

Lin JM, He CT, Liao PQ, Lin RB, Zhang JP - Sci Rep (2015)

Bottom Line: Separation of highly similar molecules and understanding the underlying mechanism are of paramount theoretical and practical importance, but visualization of the host-guest structure, energy, or dynamism is very difficult and many details have been overlooked.Here, we report a new porous coordination polymer featuring hierarchical porosity and delicate flexibility, in which the three structural isomers of xylene (also similar disubstituted benzene derivatives) can be efficiently separated with an elution sequence inversed with those for conventional mechanisms.More importantly, the separation mechanism is comprehensively and quantitatively visualized by single-crystal X-ray crystallography coupled with multiple computational simulation methods, in which the small apertures not only fit best the smallest para-isomer like molecular sieves, but also show seemingly trivial yet crucial structural alterations to distinguish the meta- and ortho-isomers via a gating mechanism, while the large channels allow fast guest diffusion and enable the structural/energetic effects to be accumulated in the macroscopic level.

View Article: PubMed Central - PubMed

Affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, P.R. China.

ABSTRACT
Separation of highly similar molecules and understanding the underlying mechanism are of paramount theoretical and practical importance, but visualization of the host-guest structure, energy, or dynamism is very difficult and many details have been overlooked. Here, we report a new porous coordination polymer featuring hierarchical porosity and delicate flexibility, in which the three structural isomers of xylene (also similar disubstituted benzene derivatives) can be efficiently separated with an elution sequence inversed with those for conventional mechanisms. More importantly, the separation mechanism is comprehensively and quantitatively visualized by single-crystal X-ray crystallography coupled with multiple computational simulation methods, in which the small apertures not only fit best the smallest para-isomer like molecular sieves, but also show seemingly trivial yet crucial structural alterations to distinguish the meta- and ortho-isomers via a gating mechanism, while the large channels allow fast guest diffusion and enable the structural/energetic effects to be accumulated in the macroscopic level.

No MeSH data available.


Related in: MedlinePlus

The 3D coordination network and local coordination/pore structures.The quadrilateral aperture (defined by the yellow sticks) is shown in the space-filling mode to highlight its effective aperture size/shape.
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f1: The 3D coordination network and local coordination/pore structures.The quadrilateral aperture (defined by the yellow sticks) is shown in the space-filling mode to highlight its effective aperture size/shape.

Mentions: Solvothermal reaction of 4,4’-(2-(pyridin-2-yl)-1H-imidazole-4,5-diyl)dibenzoic acid (H3pidba) and ZnCl2 in N,N-dimethylformamide (DMF) gave light yellow block crystals of a new metal carboxylate framework [Zn(Hpidba)]∙2.6DMF∙H2O (MCF-50, 1∙g) in high yield. SCXRD revealed that 1∙g processes a high-symmetry (space group R-3) three-dimensional (3D) non-interpenetrated coordination network (Table S1 and Figures S1-S2) and a hierarchical pore system, in which large 1D hexagonal channels (effective diameter 8.2–8.7 Å, van der Waals radii of atoms considered) running along the c-axis are interconnected through small quadrilateral apertures (effective height and width of 5.6 and 6.8 Å along the imidazole· · ·imidazole and Zn· · ·Zn diagonals, respectively) running along the a- and b-axes (Fig. 1).


Structural, energetic, and dynamic insights into the abnormal xylene separation behavior of hierarchical porous crystal.

Lin JM, He CT, Liao PQ, Lin RB, Zhang JP - Sci Rep (2015)

The 3D coordination network and local coordination/pore structures.The quadrilateral aperture (defined by the yellow sticks) is shown in the space-filling mode to highlight its effective aperture size/shape.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481377&req=5

f1: The 3D coordination network and local coordination/pore structures.The quadrilateral aperture (defined by the yellow sticks) is shown in the space-filling mode to highlight its effective aperture size/shape.
Mentions: Solvothermal reaction of 4,4’-(2-(pyridin-2-yl)-1H-imidazole-4,5-diyl)dibenzoic acid (H3pidba) and ZnCl2 in N,N-dimethylformamide (DMF) gave light yellow block crystals of a new metal carboxylate framework [Zn(Hpidba)]∙2.6DMF∙H2O (MCF-50, 1∙g) in high yield. SCXRD revealed that 1∙g processes a high-symmetry (space group R-3) three-dimensional (3D) non-interpenetrated coordination network (Table S1 and Figures S1-S2) and a hierarchical pore system, in which large 1D hexagonal channels (effective diameter 8.2–8.7 Å, van der Waals radii of atoms considered) running along the c-axis are interconnected through small quadrilateral apertures (effective height and width of 5.6 and 6.8 Å along the imidazole· · ·imidazole and Zn· · ·Zn diagonals, respectively) running along the a- and b-axes (Fig. 1).

Bottom Line: Separation of highly similar molecules and understanding the underlying mechanism are of paramount theoretical and practical importance, but visualization of the host-guest structure, energy, or dynamism is very difficult and many details have been overlooked.Here, we report a new porous coordination polymer featuring hierarchical porosity and delicate flexibility, in which the three structural isomers of xylene (also similar disubstituted benzene derivatives) can be efficiently separated with an elution sequence inversed with those for conventional mechanisms.More importantly, the separation mechanism is comprehensively and quantitatively visualized by single-crystal X-ray crystallography coupled with multiple computational simulation methods, in which the small apertures not only fit best the smallest para-isomer like molecular sieves, but also show seemingly trivial yet crucial structural alterations to distinguish the meta- and ortho-isomers via a gating mechanism, while the large channels allow fast guest diffusion and enable the structural/energetic effects to be accumulated in the macroscopic level.

View Article: PubMed Central - PubMed

Affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, P.R. China.

ABSTRACT
Separation of highly similar molecules and understanding the underlying mechanism are of paramount theoretical and practical importance, but visualization of the host-guest structure, energy, or dynamism is very difficult and many details have been overlooked. Here, we report a new porous coordination polymer featuring hierarchical porosity and delicate flexibility, in which the three structural isomers of xylene (also similar disubstituted benzene derivatives) can be efficiently separated with an elution sequence inversed with those for conventional mechanisms. More importantly, the separation mechanism is comprehensively and quantitatively visualized by single-crystal X-ray crystallography coupled with multiple computational simulation methods, in which the small apertures not only fit best the smallest para-isomer like molecular sieves, but also show seemingly trivial yet crucial structural alterations to distinguish the meta- and ortho-isomers via a gating mechanism, while the large channels allow fast guest diffusion and enable the structural/energetic effects to be accumulated in the macroscopic level.

No MeSH data available.


Related in: MedlinePlus