Electronic and magnetic properties of DUT-8(Ni)

Abstract

First principles calculations using density functional theory (DFT) have been performed to investigate the electronic and magnetic properties of DUT-8(Ni) (DUT - Dresden University of Technology). This flexible metal-organic framework (MOF) exists in two crystalline forms: DUT-8(Ni)open and DUT-8(Ni)closed. To identify the energetically favoured magnetic ordering, the density of states (DOS) and the energy difference between a low-spin (LS) and a high-spin (HS) coupling ΔELS-HS for those crystalline structures have been computed. Calculations on supercells have been carried out to include a variety of different magnetic couplings beyond a single unit cell. Several molecular model systems have been employed to further investigate the magnetic behaviour by introducing a diversity of chemical environments to the magnetic centers. The magnetic ground state of both crystalline structures has been found to be the low-spin state (S = 0). This low-spin ordering can be seen in the DOS as well as from ΔELS-HS calculations. Additionally, the calculations on the supercells confirm that the local character of the ordering (i.e. within the Ni dimers) is the most favoured one. However, the model systems indicate a change from the low-spin (S = 0) to a high-spin (S ≠ 0) ordering by introducing certain alterations into the chemical environment. Such alterations could be incorporated into the crystalline systems which should lead to similar results.

Screening for high-spin metal organic frameworks (MOFs): density functional theory study on DUT-8(M1,M2) (with Mi = V,…,Cu)

“…Recently we described the electronic and magnetic properties of the flexible metal organic framework DUT-8(Ni) (see Trepte et al 5 ). Flexible means that this MOF has an open and a closed phase.…”

Interpretation and Automatic Generation of Fermi‐Orbital Descriptors

“…Density functional theory (DFT) is one of the most commonly used electronic structure methods. Its popularity comes from its efficiency to calculate properties with reasonable accuracy for a range of systems including atoms, molecules, clusters, and condensed matter . While DFT is in principle exact, the exchange‐correlation functional E xc needs to be approximated to solve the Kohn–Sham (KS) equations in practical calculations.…”

“…Its popularity comes from its efficiency to calculate properties with reasonable accuracy for a range of systems including atoms, molecules, [3][4][5][6] clusters, [7] and condensed matter. [8][9][10][11][12][13][14][15] While DFT is in principle exact, the exchange-correlation functional E xc needs to be approximated to solve the Kohn-Sham (KS) equations in practical calculations. These density functional approximations (DFAs) often work well, but are known to produce incorrect results for rather simple cases like the dissociation of the H 2 molecule [16] or band gaps in semiconductors that are far from experimental values.…”

A Ligand Field Molecular Mechanics Study of CO2‐Induced Breathing in the Metal–Organic Framework DUT‐8(Ni)

“…Motivated by its outstanding properties, DUT-8(Ni) is being investigated extensively recently. [12][13][14][15][16][17][18][19][20][21][22][23] Some examples of the properties of interest are the enormous volume change upon opening (more than 140 %), [14] its isomorphism, [22] the property dependence on the metal center, [14] and crystallite size effects. [19] Alzahrani and Deeth [24] already employed LFMM to investigate clusters of Zn 2 (bdc) 2 (dabco) and showed the applicability to this structurally related flexible MOF.…”