scholarly journals Triplet Dynamic Nuclear Polarization of Guest Molecules through Induced Fit in a Flexible Metal-Organic Framework

2021 ◽  
Author(s):  
Saiya Fujiwara ◽  
Naoto Matsumoto ◽  
Koki Nishimura ◽  
Nobuo Kimizuka ◽  
Kenichiro Tateishi ◽  
...  
Keyword(s):  
Dynamic Nuclear Polarization ◽  
Room Temperature ◽  
Nuclear Polarization ◽  
Metal Organic Framework ◽  
Induced Fit ◽  
Guest Molecules ◽  
Metal Organic ◽  
Target Molecules ◽  
Flexible Metal ◽  
Organic Framework

Dynamic nuclear polarization utilizing photoexcited triplet electrons (triplet-DNP) has great potential for room-temperature hyperpolarization of nuclear spins. However, the polarization transfer to molecules of interest remains a challenge due to the fast spin relaxation and weak interaction with target molecules at room temperature in conventional host materials. Here, we demonstrate the first example of DNP of guest molecules in a porous material at around room temperature by utilizing the induced-fit-type structural transformation of a crystalline yet flexible metal-organic framework (MOF). In contrast to the usual hosts, 1H spin-lattice relaxation time becomes longer by accommodating a pharmaceutical model target 5-fluorouracil as the flexible MOF changes its structure upon guest accommodation to maximize the host-guest interactions. Combined with triplet-DNP and cross-polarization, this system realizes an enhanced 19F-NMR signal of guest target molecules at around room temperature.

Probing Time Dependent Phase Transformation in a Flexible Metal-Organic Framework with Nanoindentation

2021 ◽  
Author(s):  
Prakash Kanoo ◽  
Manish Kumar Mishra ◽  
Arpan Hazra
Keyword(s):  
Phase Transformation ◽  
Phase Transitions ◽  
Room Temperature ◽  
Metal Organic Framework ◽  
Time Dependent ◽  
Guest Molecules ◽  
Nanoindentation Technique ◽  
Metal Organic ◽  
Flexible Metal ◽  
Organic Framework

Phase transformation in a flexible metal-organic framework, {[Zn4(1,4-NDC)4(1,2-BPE)2]•xSolvent}n, which loses guest molecules rapidly at room temperature, leading to several phase transitions, is examined using nanoindentation technique. Nanoindentation results reveal time...

Solvent exchange in a metal–organic framework single crystal monitored by dynamicin situX-ray diffraction

2017 ◽  
Vol 73 (4) ◽  
pp. 669-674 ◽  
Author(s):  
Jordan M. Cox ◽  
Ian M. Walton ◽  
Gage Bateman ◽  
Cassidy A. Benson ◽  
Travis Mitchell ◽  
...  
Keyword(s):  
Rational Design ◽  
Metal Organic Framework ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
Time Resolved ◽  
Ethanol Solvate ◽  
Significant Step ◽  
Metal Organic ◽  
Flexible Metal ◽  
Organic Framework

Understanding the processes by which porous solid-state materials adsorb and release guest molecules would represent a significant step towards developing rational design principles for functional porous materials. To elucidate the process of liquid exchange in these materials, dynamicin situX-ray diffraction techniques have been developed which utilize liquid-phase chemical stimuli. Using these time-resolved diffraction techniques, the ethanol solvation process in a flexible metal–organic framework [Co(AIP)(bpy)0.5(H2O)]·2H2O was examined. The measurements provide important insight into the nature of the chemical transformation in this system including the presence of a previously unreported neat ethanol solvate structure.

A Highly Flexible Metal-Organic Framework Constructed from Asymmetric Flexible Linkers and Heptanuclear Zinc Carboxylate Secondary Building Units and its Anisotropic Dynamic Responses Exhibited During Guest Removal and Single Crystal Coordinated Solvent Exchange

2019 ◽  
Author(s):  
Elliot J Carrington ◽  
Rémi Pétuya ◽  
Rebecca K Hylton ◽  
Yong Yan ◽  
Dmytro Antypov ◽  
...  
Keyword(s):  
Metal Organic Framework ◽  
Structural Response ◽  
Dynamic Responses ◽  
Solvent Exchange ◽  
Void Space ◽  
Guest Molecules ◽  
Secondary Building Units ◽  
Metal Organic ◽  
Flexible Metal ◽  
Organic Framework

<p>A new porous and flexible metal-organic framework (MOF) has been synthesised from the flexible asymmetric linker N-(4-Carboxyphenyl)succinamate (CSA) and heptanuclear zinc oxo-clusters of formula [Zn<sub>7</sub>O<sub>2</sub>(Carboxylate)<sub>10</sub>DMF<sub>2</sub>] involving two coordinated terminal DMF ligands. The structural response of this MOF to the removal or exchange of its guest molecules has been probed using a combination of experimental and computational approaches. The topology of the material, involving double linker connections in the <i>a</i> and <i>b</i> directions and single linker connections along the <i>c</i> axis, is shown to be key in the materials anisotropic response. The <i>a</i> and <i>b</i> directions remain locked during guest removal, while the <i>c</i> axis linker undergoes large changes significantly reducing the material’s void space. The changes to the <i>c</i> axis linker involve a combination of a hinge motion on the linker’s rigid side and conformational rearrangements on its flexible end, which were probed in detail during this process despite the presence of crystallographic disorder along this axis which prevented accurate characterisation by experimental methods alone. While inactive during guest removal, the flexible ends of the <i>a</i> and <i>b</i> axis linkers are observed to play a prominent role during DMF to DMSO solvent exchange, facilitating the exchange reaction arising in the cluster.</p>

A Highly Flexible Metal-Organic Framework Constructed from Asymmetric Flexible Linkers and Heptanuclear Zinc Carboxylate Secondary Building Units and its Anisotropic Dynamic Responses Exhibited During Guest Removal and Single Crystal Coordinated Solvent Exchange

2019 ◽  
Author(s):  
Elliot J Carrington ◽  
Rémi Pétuya ◽  
Rebecca K Hylton ◽  
Yong Yan ◽  
Dmytro Antypov ◽  
...  
Keyword(s):  
Metal Organic Framework ◽  
Structural Response ◽  
Dynamic Responses ◽  
Solvent Exchange ◽  
Void Space ◽  
Guest Molecules ◽  
Secondary Building Units ◽  
Metal Organic ◽  
Flexible Metal ◽  
Organic Framework

<p>A new porous and flexible metal-organic framework (MOF) has been synthesised from the flexible asymmetric linker N-(4-Carboxyphenyl)succinamate (CSA) and heptanuclear zinc oxo-clusters of formula [Zn<sub>7</sub>O<sub>2</sub>(Carboxylate)<sub>10</sub>DMF<sub>2</sub>] involving two coordinated terminal DMF ligands. The structural response of this MOF to the removal or exchange of its guest molecules has been probed using a combination of experimental and computational approaches. The topology of the material, involving double linker connections in the <i>a</i> and <i>b</i> directions and single linker connections along the <i>c</i> axis, is shown to be key in the materials anisotropic response. The <i>a</i> and <i>b</i> directions remain locked during guest removal, while the <i>c</i> axis linker undergoes large changes significantly reducing the material’s void space. The changes to the <i>c</i> axis linker involve a combination of a hinge motion on the linker’s rigid side and conformational rearrangements on its flexible end, which were probed in detail during this process despite the presence of crystallographic disorder along this axis which prevented accurate characterisation by experimental methods alone. While inactive during guest removal, the flexible ends of the <i>a</i> and <i>b</i> axis linkers are observed to play a prominent role during DMF to DMSO solvent exchange, facilitating the exchange reaction arising in the cluster.</p>

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