Hidden ordered structure in the archetypical Fe(pyrazine)[Pt(CN)<sub>4</sub>] spin-crossover porous coordination compound

Fernández-Blanco, Ángel; Lorenzo-Mariano, Antonio; Piñeiro‐López, Lucía; Real, José Antonio; Costa, José Sánchez; Poloni, Roberta; Rodríguez-Velamazán, J. A.

doi:10.1039/d2ce00895e

Cited by 7 publications

(5 citation statements)

References 53 publications

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“…To investigate its influence, a series of band structure and absorption spectral calculations were performed which are depicted in Figure . Supercells with a parallel and disordered arrangement of pz rings used for simulations are also provided from the Z axis view, similarly as in the previous work . In general, DOS spectra for the LS state exhibit a similar distribution of states corresponding to each atomic element with respect to the parallel supercell (compare with Figure ).…”

Section: Resultsmentioning

confidence: 96%

Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)₂Pt(CN)₄] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks

Olejnik

Kopeć

Maskowicz

et al. 2023

ACS Appl. Mater. Interfaces

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Paramount spin-crossover properties of the 3D-Hoffman metalorganic framework (MOF) [Fe(pz)2Pt(CN)4] are generally described on the basis of the ligand field theory, which provides adequate insight into theoretical and simulation analysis of spintronic complexes. However, the ligand field approximation does not take into account the 3D periodicity of the actual complex lattice and surface effects and therefore cannot predict a full-scale periodic structure without utilizing more advanced methods. Therefore, in this paper, the electronic properties of the exemplar MOF were analyzed from the band structure perspective in low-spin (LS) and high-spin (HS) states. The density-of-states spectra determined for both spin-up and spin-down electrons of Fe d6 orbitals indicate spin–orbital splitting and delocalization for HS due to spin polarization in the iron atom ligand field. Presence of the surface states in the real crystal causes a red shift of the metal–metal charge transfer (MMCT) and metal–ligand charge transfer (MLCT) peaks for both HS and LS states. The addition of residual water molecules and disorder among the pyrazine rings reveal additional influences on the positions of the pyrazine band and, therefore, on the absorption spectra of the crystal. The results show a magnification of the peak correlated with the MLCT in the HS state and a significant red shift of the LS characteristic absorption band. The presented approach involving band structure analysis delivers a more complete image of the electronic properties of the [Fe(pz)2Pt(CN)4] crystalline network and can be a landmark for insightful studies of other MOFs.

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Section: Resultsmentioning

confidence: 96%

Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)₂Pt(CN)₄] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks

Olejnik

Kopeć

Maskowicz

et al. 2023

ACS Appl. Mater. Interfaces

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“…As explained in section I, by assuming the entropic and vibrational contributions as those reported previously [24][25][26] , and by taking into account the error in the density-corrected method 21 , we estimate the target values of adiabatic energy differences between -0.1 and 0.6 eV for a spin crossover near room temperature. We stress here that while the calculation of T 1/2 is possible by evaluating all the terms that enter the free energy 22,23,63,64 , this is beyond the scope of this work. To provide a quantitative evaluation of the efficiency of the proposed mechanism with respect to a more standard temperature-induced gas release process, one would require, besides the evaluation of T 1/2 , the calculation of the gas uptake as a function of the gas pressure and temperature (thus, right below and above T 1/2 ) by employing e.g.…”

Section: Discussionmentioning

confidence: 99%

Perspective from a Hubbard U-density corrected scheme towards a spin crossover-mediated change in gas affinity

Mariano,

Fernández-Blanco,

Poloni

2023

The Journal of Chemical Physics

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By employing a recently proposed Hubbard U density-corrected scheme within density functional theory, we provide design principles towards the design of materials exhibiting a spin crossover-assisted gas release. Small molecular fragments are used as case study to identify two main mechanisms behind the change in binding energy upon spin transitions. The feasibility of the proposed mechanism in porous crystals is assessed by correlating the change in binding energy of CO2, CO, N2, and H2, upon spin crossover, with the adiabatic energy difference associated with the spin state change of the square-planar metal in Hofmann-type clathrates (M = Fe, Mn, Ni). A few promising cases are identified for the adsorption of intermediate ligand field strength molecules such as N2 and H2. The latter stands out as the most original result as the strong interaction in low spin, as expected from a Kubas mechanism, results in a large change in binding energy. This work provides a general perspective towards the engineering of open-metal site frameworks exhibiting local environments designed to have a spin crossover upon adsorption of specific gas molecules.

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“…This assumption is motivated by recent studies reporting these values of enthalpy change associated with near-room temperature spin crossover for several Fe(II)-based molecular 23 and crystalline compounds. 24 We stress here that while the calculation of T 1/2 is possible by evaluating all the terms that enter the free energy, [55][56][57][58] this is beyond the scope of this work.…”

Section: Discussionmentioning

confidence: 99%

Spin Crossover-Mediated Change in Gas Affinity in Metal-Organic Frameworks: Perspective from A Hubbard U-Density Corrected Scheme

Mariano

Blanco

Poloni

2023

Preprint

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The development of strategies to efficiently capture and release gas is one of the most urgent topics in modern applied chemistry. In this respect, the modulation of the affinity for the gas molecule upon application of an external stimulus appears as fascinating strategy to reduce the energy penalty of the release process. In this work we provide the proof- of-concept for a novel temperature-induced gas release strategy in porous materials with desorption occurring upon a spin crossover transition of metal center exhibiting an open coordination. By employing a recently proposed Hubbard-U density- corrected scheme within density-functional theory we demonstrate the feasibility of the proposed process from a thermodynamic point of view by correlating the change in binding energy of several gas molecules upon spin crossover with the adiabatic energy difference associated with the spin state change for a series of six porous coordination polymers. The case of H2 ad- sorption stands out as the most promising and yet novel result with implications for a non-cryogenic storage technology.

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Hidden ordered structure in the archetypical Fe(pyrazine)[Pt(CN)₄] spin-crossover porous coordination compound

Abstract: Despite the fact that Fe(pyrazine)[MII(CN)4] (where MII is a metal in open square-planar configuration, namely Pt, Pd, Ni) is one of the most thoroughly studied families of spin-crossover compounds, its...

Cited by 7 publications

References 53 publications

Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)₂Pt(CN)₄] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks

Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)₂Pt(CN)₄] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks

Perspective from a Hubbard U-density corrected scheme towards a spin crossover-mediated change in gas affinity

Spin Crossover-Mediated Change in Gas Affinity in Metal-Organic Frameworks: Perspective from A Hubbard U-Density Corrected Scheme

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Hidden ordered structure in the archetypical Fe(pyrazine)[Pt(CN)4] spin-crossover porous coordination compound

Abstract: Despite the fact that Fe(pyrazine)[MII(CN)4] (where MII is a metal in open square-planar configuration, namely Pt, Pd, Ni) is one of the most thoroughly studied families of spin-crossover compounds, its...

Cited by 7 publications

References 53 publications

Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)2Pt(CN)4] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks

Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)2Pt(CN)4] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks

Perspective from a Hubbard U-density corrected scheme towards a spin crossover-mediated change in gas affinity

Spin Crossover-Mediated Change in Gas Affinity in Metal-Organic Frameworks: Perspective from A Hubbard U-Density Corrected Scheme

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Hidden ordered structure in the archetypical Fe(pyrazine)[Pt(CN)₄] spin-crossover porous coordination compound

Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)₂Pt(CN)₄] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks

Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)₂Pt(CN)₄] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks