Ultrafast Water H-Bond Rearrangement in a Metal–Organic Framework Probed by Femtosecond Time-Resolved Infrared Spectroscopy

Valentine, Mason L.; Yin, Guoxin; Dincă, Mircea; Xiong, Wei

doi:10.1021/jacs.3c01728

Cited by 18 publications

(11 citation statements)

References 49 publications

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“…Since the water hydrogen-bond network in CALF-20 becomes more connected and connected as the relative humidity increases (Figure A), the slower reorientation of the H 2 O molecules at high RH values can therefore be attributed to increasing water–water interactions. Similar conclusions were drawn in experimental and computational studies of water adsorbed in [Zn( l -L)(Cl)], Co 2 Cl 2 BTDD, and Ni 2 Cl 2 BTDD . Interestingly, Table indicates that the presence of CO 2 molecules within the framework leads to larger τ 2 values for the H 2 O molecules at each RH value.…”

Section: Resultssupporting

confidence: 82%

Elucidating the Competitive Adsorption of H₂O and CO₂ in CALF-20: New Insights for Enhanced Carbon Capture Metal–Organic Frameworks

Ho,

Paesani

2023

ACS Appl. Mater. Interfaces

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In light of the pressing need for efficient carbon capture solutions, our study investigates the simultaneous adsorption of water (H 2 O) and carbon dioxide (CO 2 ) as a function of relative humidity in CALF-20, a highly scalable and stable metal− organic framework (MOF). Advanced computer simulations reveal that due to their similar interactions with the framework, H 2 O and CO 2 molecules compete for the same binding sites, occupying similar void regions within the CALF-20 pores. This competition results in distinct thermodynamic and dynamical behaviors of H 2 O and CO 2 molecules, depending on whether one or both guest species are present. Notably, the presence of CO 2 molecules forces the H 2 O molecules to form more connected hydrogen-bond networks within smaller regions, slowing water reorientation dynamics and decreasing water entropy. Conversely, the presence of water speeds up the reorientation of CO 2 molecules, decreases the CO 2 entropy, and increases the propensity for CO 2 to be adsorbed within the framework due to stronger water-mediated interactions. Due to the competition for the same void spaces, both H 2 O and CO 2 molecules exhibit slower diffusion when molecules of the other guest species are present. These findings offer valuable strategies and insights into enhancing the differential affinity of H 2 O and CO 2 for MOFs specifically designed for carbon capture applications.

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Section: Resultssupporting

confidence: 82%

Elucidating the Competitive Adsorption of H₂O and CO₂ in CALF-20: New Insights for Enhanced Carbon Capture Metal–Organic Frameworks

Ho,

Paesani

2023

ACS Appl. Mater. Interfaces

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“…Notably, there is minimal adsorption–desorption hysteresis for all of the water isotherms, similar to adsorption in related azolate frameworks (Figure S6.1). Minimal hysteretic loops in chemically similar materials has been ascribed to fast pore water dynamics (i.e., facile reorientation of water within the pores), potentially driven by a large number of framework hydrogen-bond acceptors . The lack of a large hysteresis loop (and potentially the cause of fast water dynamics in related materials) concurrent with sharp water uptake may also be due to the capillary condensation occurring in a pore with a diameter slightly larger than the critical diameter for hysteresis at the measured temperature.…”

Section: Resultsmentioning

confidence: 97%

Tunable Low–Relative Humidity and High–Capacity Water Adsorption in a Bibenzotriazole Metal–Organic Framework

Alezi,

Oppenheim,

Sarver

et al. 2023

J. Am. Chem. Soc.

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Materials capable of selectively adsorbing or releasing water can enable valuable applications ranging from efficient humidity and temperature control to the direct atmospheric capture of potable water. Despite recent progress in employing metal−organic frameworks (MOFs) as privileged water sorbents, developing a readily accessible, water-stable MOF platform that can be systematically modified for high water uptake at low relative humidity remains a significant challenge. We herein report the development of a tunable MOF that efficiently captures atmospheric water (up to 0.78 g water/g MOF) across a range of uptake humidity (27−45%) employing a readily accessible Zn bibenzotriazolate MOF, CFA-1 ([Zn 5 (OAc) , as a base for subsequent diversification. Controlling the metal identity (zinc, nickel) and coordinating nonstructural anion (acetate, chloride) via postsynthetic exchange modulates the relative humidity of uptake, facilitating the use of a single MOF scaffold for a diverse range of potential water sorption applications. We further present a fundamental theory dictating how continuous variation of the pore environment affects the relative humidity of uptake. Exchange of substituents preserves capacity for water sorption, increases hydrolytic stability (with 5.7% loss in working capacity over 450 water adsorption−desorption cycles for the nickel-chloride-rich framework), and enables continuous modulation for the relative humidity of pore condensation. This combination of stability and tunability within a synthetically accessible framework renders Ni-incorporated M 5 X 4 bibta 3 promising materials for practical water sorption applications.

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“…Fast, reversible dislocation of the H atom along the O–O axis, however, should not completely scramble the OH stretch dipole orientation. Small fluctuations of the H/D atoms around the equilibrium position should likewise result in partial anisotropy decay. , While rapid fluctuations of the H/D atom positions certainly contribute to the early time orientational dynamics, they should not contribute to the longer time scales nor result in complete decay of the anisotropy.…”

Section: Resultsmentioning

confidence: 99%

Investigating Intramolecular H Atom Transfer Dynamics in β-Diketones with Ultrafast Infrared Spectroscopies and Theoretical Modeling

Dean,

Winkler,

Boyer

et al. 2023

J. Phys. Chem. A

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The vibrational signatures and ultrafast dynamics of the intramolecular H-bond in a series of β-diketones are investigated with 2D IR spectroscopy and computational modeling. The chosen β-diketones exhibit a range of H atom donor–acceptor distances and asymmetry along the H atom transfer coordinate that tunes the intramolecular H-bond strength. The species with the strongest H-bonds are calculated to have very soft H atom potentials, resulting in highly red-shifted OH stretch fundamental frequencies and dislocation of the H atom upon vibrational excitation. These soft potentials lead to significant coupling to the other normal mode coordinates and give rise to the very broad vibrational signatures observed experimentally. The 2D IR spectra in both the OH and OD stretch regions of the light and deuterated isotopologues reveal broadened and long-lived ground-state bleach signatures of the vibrationally hot molecules. Polarization-sensitive transient absorption measurements in the OH and OD stretch regions reveal notable isotopic differences in orientational dynamics. Orientational relaxation was measured to occur on ∼600 fs and ∼2 ps time scales for the light and deuterated isotopologues, respectively. The orientational dynamics are interpreted in terms of activated H/D atom transfer events driven by collective intramolecular structural rearrangements.

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Ultrafast Water H-Bond Rearrangement in a Metal–Organic Framework Probed by Femtosecond Time-Resolved Infrared Spectroscopy

Cited by 18 publications

References 49 publications

Elucidating the Competitive Adsorption of H₂O and CO₂ in CALF-20: New Insights for Enhanced Carbon Capture Metal–Organic Frameworks

Elucidating the Competitive Adsorption of H₂O and CO₂ in CALF-20: New Insights for Enhanced Carbon Capture Metal–Organic Frameworks

Tunable Low–Relative Humidity and High–Capacity Water Adsorption in a Bibenzotriazole Metal–Organic Framework

Investigating Intramolecular H Atom Transfer Dynamics in β-Diketones with Ultrafast Infrared Spectroscopies and Theoretical Modeling

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Ultrafast Water H-Bond Rearrangement in a Metal–Organic Framework Probed by Femtosecond Time-Resolved Infrared Spectroscopy

Cited by 18 publications

References 49 publications

Elucidating the Competitive Adsorption of H2O and CO2 in CALF-20: New Insights for Enhanced Carbon Capture Metal–Organic Frameworks

Elucidating the Competitive Adsorption of H2O and CO2 in CALF-20: New Insights for Enhanced Carbon Capture Metal–Organic Frameworks

Tunable Low–Relative Humidity and High–Capacity Water Adsorption in a Bibenzotriazole Metal–Organic Framework

Investigating Intramolecular H Atom Transfer Dynamics in β-Diketones with Ultrafast Infrared Spectroscopies and Theoretical Modeling

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Elucidating the Competitive Adsorption of H₂O and CO₂ in CALF-20: New Insights for Enhanced Carbon Capture Metal–Organic Frameworks

Elucidating the Competitive Adsorption of H₂O and CO₂ in CALF-20: New Insights for Enhanced Carbon Capture Metal–Organic Frameworks