Stimuli-responsive structural changes in metal–organic frameworks

Stimuli-responsive metal-organic frameworks (MOFs) exhibit dynamic, and typically reversible, structural changes upon exposure to external stimuli. This process often induces drastic changes in their adsorption properties. Herein, we present a...

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Integration of Fluorescent Functionality into Pressure Amplifying Metal-Organic Frameworks

10.26434/chemrxiv.14680335.v1 ◽

2021 ◽

Author(s):

Francesco Walenszus ◽

Jack D. Evans ◽

Volodymyr Bon ◽

Friedrich Schwotzer ◽

Irena Senkovska ◽

...

Keyword(s):

Structural Changes ◽

Gas Adsorption ◽

Metal Organic Frameworks ◽

Metal Exchange ◽

Limited Information ◽

X Ray Diffraction ◽

Metal Organic ◽

Synthetic Metal ◽

External Stimuli ◽

Highly Porous

The flexibility of soft porous crystals, i.e., their ability to respond to external stimuli with structural changes, is one of the most fascinating features of metal-organic frameworks. In addition to breathing and swelling phenomena of flexible MOFs, negative gas adsorption and pressure amplification is one of the more recent discoveries in this field, initially observed in the cubic DUT-49 framework. In recent years the structural contraction was monitored by physisorption, X‑ray diffraction, NMR and EPR techniques, providing only limited information about the electronic structure of the ligand. In this work we designed a new ligand with a fluorescent core in the linker backbone and synthesized three new MOFs, isoreticular to DUT-49, denoted as DUT‑140(M) (M - Cu, Co, Zn) crystalizing in space group. DUT‑140(Cu) can be desolvated and is highly porous with an accessible apparent surface area of 4870 m2g-1 and a pore volume of 2.59 cm3g-1. Furthermore, it shows flexibility and NGA upon adsorption of subcritical gases. DUT-140(Zn), synthesized using post-synthetic metal exchange, could only be studied with guests in the pores. In addition to the investigation of the adsorption behavior of DUT-140(Cu) spectroscopic and computational methods were used to study the light absorption properties.

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Structure and properties of dynamic metal–organic frameworks: a brief accounts of crystalline-to-crystalline and crystalline-to-amorphous transformations

CrystEngComm ◽

10.1039/c7ce02066j ◽

2018 ◽

Vol 20 (10) ◽

pp. 1322-1345 ◽

Cited By ~ 31

Author(s):

Arijit Halder ◽

Debajyoti Ghoshal

Keyword(s):

Structural Changes ◽

Metal Organic Frameworks ◽

Structure And Properties ◽

Metal Organic ◽

External Stimuli

External stimuli-driven structural changes and the associated properties of dynamic MOFs are discussed with examples.

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Integration of Fluorescent Functionality into Pressure Amplifying Metal-Organic Frameworks

10.26434/chemrxiv.14680335 ◽

2021 ◽

Author(s):

Francesco Walenszus ◽

Jack D. Evans ◽

Volodymyr Bon ◽

Friedrich Schwotzer ◽

Irena Senkovska ◽

...

Keyword(s):

Structural Changes ◽

Gas Adsorption ◽

Metal Organic Frameworks ◽

Metal Exchange ◽

Limited Information ◽

X Ray Diffraction ◽

Metal Organic ◽

Synthetic Metal ◽

External Stimuli ◽

Highly Porous

The flexibility of soft porous crystals, i.e., their ability to respond to external stimuli with structural changes, is one of the most fascinating features of metal-organic frameworks. In addition to breathing and swelling phenomena of flexible MOFs, negative gas adsorption and pressure amplification is one of the more recent discoveries in this field, initially observed in the cubic DUT-49 framework. In recent years the structural contraction was monitored by physisorption, X‑ray diffraction, NMR and EPR techniques, providing only limited information about the electronic structure of the ligand. In this work we designed a new ligand with a fluorescent core in the linker backbone and synthesized three new MOFs, isoreticular to DUT-49, denoted as DUT‑140(M) (M - Cu, Co, Zn) crystalizing in space group. DUT‑140(Cu) can be desolvated and is highly porous with an accessible apparent surface area of 4870 m2g-1 and a pore volume of 2.59 cm3g-1. Furthermore, it shows flexibility and NGA upon adsorption of subcritical gases. DUT-140(Zn), synthesized using post-synthetic metal exchange, could only be studied with guests in the pores. In addition to the investigation of the adsorption behavior of DUT-140(Cu) spectroscopic and computational methods were used to study the light absorption properties.

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Metal-Organic Framework-Based Stimuli-Responsive Polymers

Journal of Composites Science ◽

10.3390/jcs5040101 ◽

2021 ◽

Vol 5 (4) ◽

pp. 101

Author(s):

Menglian Wei ◽

Yu Wan ◽

Xueji Zhang

Keyword(s):

Metal Organic Framework ◽

Chemical Properties ◽

Stimuli Responsive ◽

Guest Molecules ◽

Stimuli Responsive Polymers ◽

Responsive Polymers ◽

Reversible Phase Transition ◽

Metal Organic ◽

External Stimuli ◽

Organic Framework

Metal-organic framework (MOF) based stimuli-responsive polymers (coordination polymers) exhibit reversible phase-transition behavior and demonstrate attractive properties that are capable of altering physical and/or chemical properties upon exposure to external stimuli, including pH, temperature, ions, etc., in a dynamic fashion. Thus, their conformational change can be imitated by the adsorption/desorption of target analytes (guest molecules), temperature or pressure changes, and electromagnetic field manipulation. MOF-based stimuli responsive polymers have received great attention due to their advanced optical properties and variety of applications. Herein, we summarized some recent progress on MOF-based stimuli-responsive polymers (SRPs) classified by physical and chemical responsiveness, including temperature, pressure, electricity, pH, metal ions, gases, alcohol and multi-targets.

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Synthesis and therapeutic potential of stimuli-responsive metal-organic frameworks

Chemical Engineering Journal ◽

10.1016/j.cej.2020.127233 ◽

2020 ◽

pp. 127233

Author(s):

Shahla Karimzadeh ◽

Siamak Javanbakht ◽

Behzad Baradaran ◽

Mohammad-Ali Shahbazi ◽

Mahmoud Hashemzaei ◽

...

Keyword(s):

Therapeutic Potential ◽

Metal Organic Frameworks ◽

Stimuli Responsive ◽

Metal Organic

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Temperature dependence of adsorption hysteresis in flexible metal organic frameworks

Communications Chemistry ◽

10.1038/s42004-020-00429-3 ◽

2020 ◽

Vol 3 (1) ◽

Cited By ~ 1

Author(s):

Shamsur Rahman ◽

Arash Arami-Niya ◽

Xiaoxian Yang ◽

Gongkui Xiao ◽

Gang (Kevin) Li ◽

...

Keyword(s):

Temperature Dependence ◽

Capillary Condensation ◽

Metal Organic Frameworks ◽

Sorption Isotherms ◽

Separation Performance ◽

Process Simulations ◽

Metal Organic ◽

Flexible Metal ◽

Pressure Swing ◽

External Stimuli

Abstract“Breathing” and “gating” are striking phenomena exhibited by flexible metal-organic frameworks (MOFs) in which their pore structures transform upon external stimuli. These effects are often associated with eminent steps and hysteresis in sorption isotherms. Despite significant mechanistic studies, the accurate description of stepped isotherms and hysteresis remains a barrier to the promised applications of flexible MOFs in molecular sieving, storage and sensing. Here, we investigate the temperature dependence of structural transformations in three flexible MOFs and present a new isotherm model to consistently analyse the transition pressures and step widths. The transition pressure reduces exponentially with decreasing temperature as does the degree of hysteresis (c.f. capillary condensation). The MOF structural transition enthalpies range from +6 to +31 kJ·mol−1 revealing that the adsorption-triggered transition is entropically driven. Pressure swing adsorption process simulations based on flexible MOFs that utilise the model reveal how isotherm hysteresis can affect separation performance.

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Cyclodextrins Modified/Coated Metal–Organic Frameworks

Materials ◽

10.3390/ma13061273 ◽

2020 ◽

Vol 13 (6) ◽

pp. 1273 ◽

Cited By ~ 3

Author(s):

Huacheng Zhang ◽

Zhaona Liu ◽

Jian Shen

Keyword(s):

Hybrid Materials ◽

Metal Organic Frameworks ◽

Supramolecular Interactions ◽

Future Research ◽

Covalent Bonds ◽

Characterization Methods ◽

Coated Metal ◽

Metal Organic ◽

Future Research Directions ◽

External Stimuli

Recent progress about a novel organic–inorganic hybrid materials, namely cyclodextrins (CDs) modified/coated metal–organic frameworks (MOFs) is summarized by using a special categorization method focusing on the interactions between CDs and MOFs moieties, such as ligand–metal cations interactions, supramolecular interactions including host–guest interactions and hydrogen bonding, as well as covalent bonds. This review mainly focuses on the interactions between CDs and MOFs and the strategy of combining them together, diverse external stimuli responsiveness of CDs-modified/coated MOFs, as well as applications of these hybrid materials to drug delivery and release system, catalysis and detection materials. Additionally, due to the importance of investigating advanced chemical architectures and physiochemical properties of CDs-modified/coated MOFs, a separate section is involved in diverse characterization methods and instruments. Furthermore, this minireview also foresees future research directions in this rapidly developing field.

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Stimuli-responsive metal–organic frameworks gated by pillar[5]arene supramolecular switches

Chemical Science ◽

10.1039/c4sc03749a ◽

2015 ◽

Vol 6 (3) ◽

pp. 1640-1644 ◽

Cited By ~ 154

Author(s):

Li-Li Tan ◽

Haiwei Li ◽

Yu-Chen Qiu ◽

Dai-Xiong Chen ◽

Xin Wang ◽

...

Keyword(s):

Metal Organic Frameworks ◽

Stimuli Responsive ◽

Triggered Release ◽

Metal Organic ◽

Hybrid Platform ◽

First Time

Mechanized monodisperse nano metal–organic frameworks (NMOFs) gated by carboxylatopillar[5]arene (CP5) switches with bio-friendly pH-triggered release capabilities were constructed for the first time as a new stimuli-responsive theranostic hybrid platform.

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