Spin crossover metal–organic frameworks with inserted photoactive guests: on the quest to control the spin state by photoisomerization

Brachňaková, Barbora; Moncóľ, Ján; Pavlík, Jan; Šalitroš, Ivan; Bonhommeau, Sébastien; Valverde‐Muñoz, Francisco Javier; Salmon, Lionel; Molnár, Gábor; Routaboul, Lucie; Bousseksou, Azzedine

doi:10.1039/d1dt01057c

Cited by 15 publications

(9 citation statements)

References 81 publications

(21 reference statements)

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“…The table also shows a vibrational analysis for the radical anion peaks with a 532 nm pump and with a 594 nm pump (785 nm probe for both). The anion radical peak assignments were made in reference to time-resolved resonance Raman (TR3) and electrochemical SERS measurements for all molecules. ,,,− ,,− Similar to our previous BPE studies, anion radical peaks of identical mode character appear shifted toward lower wavenumbers such as the ethylene bond stretching mode coupled to ring distortion (1630 cm –1 in neutral BPE to 1550 cm –1 in anion radical BPE) and the kekule ring mode (1300 cm –1 in neutral BPE to 1240 cm –1 in anion radical BPE). This trend is observed in all five adsorbate molecules in this study when comparing the neutral to anion radical single nanoparticle SERS spectra (see Table ).…”

Section: Resultsmentioning

confidence: 69%

Modulating the Electron Affinity of Small Bipyridyl Molecules on Single Gold Nanoparticles for Plasmon-Driven Electron Transfer

et al. 2021

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Developing controlled platforms for plasmon-driven chemistry is of great importance in catalytic reactions at the nanoscale. We report anion radical formation for five bipyridyl complexes of varying degrees of electron affinity utilizing optically focused intraband (594 nm) and interband (532 nm) pump excitation of single gold nanoparticles. The surface-enhanced Raman scattering (SERS) of anion radicals for the five nonresonant adsorbed molecules, 2,2′-bipyridine (22BPY), 4,4′-bipyridine (44BPY), trans-1,2-bis(4-pyridyl)ethylene (BPE), 1,2-bis(4-pyridyl)acetylene (BPA), and 1,2-bis(4-pyridyl)ethane (BPEt), were detected using localized surface-plasmon resonance (LSPR) excitation with 785 nm. The electron affinity of the five bipyridyl complexes were determined using electrochemistry. Molecules with low electron affinity experienced higher instances of radical anion formation under a plasmon-coupled intraband electron transfer excitation (594 nm), whereas molecules with high electron affinity showed a preference for anion radical formation under direct interband electron transfer excitation (532 nm). The lowest unoccupied molecular orbital (LUMO) energy levels for low electron affinity surface-bound molecules (22BPY, BPEt) are on average ∼0.43 eV higher than high electron affinity surface-bound molecules (BPA, BPE, 44BPY), as calculated using time-dependent density functional theory, elucidating the importance of plasmon coupling to energy levels that facilitate charge transfer pathways. We also show the ability to “activate” high versus low electron affinity single nanoparticles with the choice of pump excitation wavelength. The findings show the complex interplay between molecular electron affinity, orbital overlap with the density of states of the plasmonic metal, and excitation energetics of the pump laser wavelength. Potential applications of this work include enhanced control over molecular scale catalysis, biosensor design, and solar energy capture.

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Section: Resultsmentioning

confidence: 69%

Modulating the Electron Affinity of Small Bipyridyl Molecules on Single Gold Nanoparticles for Plasmon-Driven Electron Transfer

et al. 2021

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“…Moreover, MOFs allow for tailoring a framework environment through skeleton modification or wall grafting (Scheme ). ,− ,,,− ,,− Furthermore, photoswitch behavior can be tuned by incorporation of different guest molecules within framework cavities, including the presence or absence of solvent molecules of different polarity. ,,− Thus, in this section, we discuss the advantages of coordination of photoresponsive molecules to metals in well-defined crystalline scaffolds and the corresponding effects on physicochemical properties of the material, as well as outline the potential scientific gaps in this area.…”

Section: Metal–organic Frameworkmentioning

confidence: 99%

Metal–Photoswitch Friendship: From Photochromic Complexes to Functional Materials

et al. 2022

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Cooperative metal–photoswitch interfaces comprise an application-driven field which is based on strategic coupling of metal cations and organic photochromic molecules to advance the behavior of both components, resulting in dynamic molecular and material properties controlled through external stimuli. In this Perspective, we highlight the ways in which metal–photoswitch interplay can be utilized as a tool to modulate a system’s physicochemical properties and performance in a variety of structural motifs, including discrete molecular complexes or cages, as well as periodic structures such as metal–organic frameworks. This Perspective starts with photochromic molecular complexes as the smallest subunit in which metal–photoswitch interactions can occur, and progresses toward functional materials. In particular, we explore the role of the metal–photoswitch relationship for gaining fundamental knowledge of switchable electronic and magnetic properties, as well as in the design of stimuli-responsive sensors, optically gated memory devices, catalysts, and photodynamic therapeutic agents. The abundance of stimuli-responsive systems in the natural world only foreshadows the creative directions that will uncover the full potential of metal–photoswitch interactions in the coming years.

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“…∼ 2.9 Å) and volume ( c.a. ∼ 3.7 Å 3 ) associated with the isomerization ( i. e ., trans ‐to‐ cis ) stands a potential barrier for the photoconversion of these large guest molecules within the host framework [83] . This new strategy termed as guest‐driven light‐induced spin change (GD‐LISC), not only establishes a new mechanism for spin‐state switching but also directs toward the development of a new generation of photo‐responsive magnetic materials.…”

Section: Spin‐state Switching In Molecular Hofmann‐ Type Frameworkmentioning

confidence: 99%

Spin‐State Modulation in Fe^II‐Based Hofmann‐Type Coordination Polymers: From Molecules to Materials

Kumar

Paul

Mondal

et al. 2022

The Chemical Record

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Spin crossover complexes that reversibly interconvert between two stable states imitate a binary state of 0 and 1, delivering a promising possibility to address the data processing concept in smart materials. Thus, a comprehensive understanding of the modulation of magnetic transition between high spin and low spin and the factors responsible for stabilizing the spin states is an essential theme in modern materials design. In this context, the present review attempts to provide a concise outline of the design strategy employed at the molecular level for fine-tuning the spin-state switching in Fe II -based Hofmann-type coordination polymers and their effects on the optical and magnetic response. In addition, development towards the nanoscale architectures of HCPs, i. e., in terms of nanoparticles and thin films, are emphasized to bridge the gap between the laboratory and reality.

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Spin crossover metal–organic frameworks with inserted photoactive guests: on the quest to control the spin state by photoisomerization

Cited by 15 publications

References 81 publications

Modulating the Electron Affinity of Small Bipyridyl Molecules on Single Gold Nanoparticles for Plasmon-Driven Electron Transfer

Modulating the Electron Affinity of Small Bipyridyl Molecules on Single Gold Nanoparticles for Plasmon-Driven Electron Transfer

Metal–Photoswitch Friendship: From Photochromic Complexes to Functional Materials

Spin‐State Modulation in Fe^II‐Based Hofmann‐Type Coordination Polymers: From Molecules to Materials

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Spin crossover metal–organic frameworks with inserted photoactive guests: on the quest to control the spin state by photoisomerization

Cited by 15 publications

References 81 publications

Modulating the Electron Affinity of Small Bipyridyl Molecules on Single Gold Nanoparticles for Plasmon-Driven Electron Transfer

Modulating the Electron Affinity of Small Bipyridyl Molecules on Single Gold Nanoparticles for Plasmon-Driven Electron Transfer

Metal–Photoswitch Friendship: From Photochromic Complexes to Functional Materials

Spin‐State Modulation in FeII‐Based Hofmann‐Type Coordination Polymers: From Molecules to Materials

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Spin‐State Modulation in Fe^II‐Based Hofmann‐Type Coordination Polymers: From Molecules to Materials