Crystal Dynamics in Multi-stimuli-Responsive Entangled Metal-Organic Frameworks.
An understanding of solid-state crystal dynamics or flexibility in metal-organic frameworks (MOFs) showing multiple structural changes is highly demanding for the design of materials with potential applications in sensing and recognition. However, entangled MOFs showing such flexible behavior pose a great challenge in terms of extracting information on their dynamics because of their poor single-crystallinity. In this article, detailed experimental studies on a twofold entangled MOF (f-MOF-1) are reported, which unveil its structural response toward external stimuli such as temperature, pressure, and guest molecules. The crystallographic study shows multiple structural changes in f-MOF-1, by which the 3 D net deforms and slides upon guest removal. Two distinct desolvated phases, that is, f-MOF-1 a and f-MOF-1 b, could be isolated; the former is a metastable one and transformable to the latter phase upon heating. The two phases show different gated CO2adsorption profiles. DFT-based calculations provide an insight into the selective and gated adsorption behavior with CO2of f-MOF-1 b. The gate-opening threshold pressure of CO2adsorption can be tuned strategically by changing the chemical functionality of the linker from ethanylene (-CH2-CH2-) in f-MOF-1 to an azo (-N=N-) functionality in an analogous MOF, f-MOF-2. The modulation of functionality has an indirect influence on the gate-opening pressure owing to the difference in inter-net interaction. The framework of f-MOF-1 is highly responsive toward CO2gas molecules, and these results are supported by DFT calculations.
Chemistry and Physics of Materials Unit (CPMU), Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore-, 560064, Karnataka, India.|Department of Chemistry, School of Chemical Sciences, Central University of Haryana, Jant-Pali, Mahendergarh, 123031, Haryana, India.
Prakash
P
Kanoo
New Chemistry Unit (NCU), Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore-, 560064, Karnataka, India.
Ritesh
R
Haldar
Chemistry and Physics of Materials Unit (CPMU), Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore-, 560064, Karnataka, India.
Sandeep K
SK
Reddy
Chemistry and Physics of Materials Unit (CPMU), Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore-, 560064, Karnataka, India.
Arpan
http://orcid.org/0000-0001-7383-7416
A
Hazra
Chemistry and Physics of Materials Unit (CPMU), Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore-, 560064, Karnataka, India.
Satyanarayana
S
Bonakala
Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan.|Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan.
Ryotaro
R
Matsuda
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan.|Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan.
Susumu
S
Kitagawa
Chemistry and Physics of Materials Unit (CPMU), Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore-, 560064, Karnataka, India. bala@jncasr.ac.in.
Sundaram
S
Balasubramanian
Chemistry and Physics of Materials Unit (CPMU), Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore-, 560064, Karnataka, India. tmaji@jncasr.ac.in.|New Chemistry Unit (NCU), Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore-, 560064, Karnataka, India. tmaji@jncasr.ac.in.
Tapas Kumar
http://orcid.org/0000-0002-7700-1146
TK
Maji
breathing; carbon dioxide; metal-organic frameworks; polymorphism; selective gas adsorption