Probing the Chemical Bonding and Electron Structure of the Benzoate model for Fe-MoF-5

2013 ◽  
Vol 1548 ◽  
Author(s):  
Jun Zhang ◽  
Xiaohong Zheng ◽  
Chunsheng Liu ◽  
Zhi Zeng

ABSTRACTUsing first-principles density functional theory, we investigated the chemical bonding and electronic structure of the metal-organic-framework with individual structural element OFe4(CO2Ph)6. The calculations showed that there is no obvious structural difference between OFe4(CO2Ph)6 and OZn4(CO2Ph)6. The analysis of electronic structure and chemical bonding reveals that the Fe-O has mainly ionic interaction and partial covalent interaction while O-C, H-C and C-C exhibit mainly covalent interactions. The finding in this paper may shed light on the synthesis of MOF-5 materials with other metal centers.

2016 ◽  
Vol 18 (11) ◽  
pp. 8075-8080 ◽  
Author(s):  
Sebastian Schwalbe ◽  
Kai Trepte ◽  
Gotthard Seifert ◽  
Jens Kortus

We present a first principles study of low-spin (LS)/high-spin (HS) screening for 3d metal centers in the metal organic framework (MOF) DUT-8(Ni).


2018 ◽  
Vol 6 (18) ◽  
pp. 8507-8513 ◽  
Author(s):  
Katrine L. Svane ◽  
Jessica K. Bristow ◽  
Julian D. Gale ◽  
Aron Walsh

The energetics and electronic structure of defects in the metal–organic framework UiO-66 is investigated using density functional theory.


2021 ◽  
Vol 7 (18) ◽  
pp. eabg2580
Author(s):  
Weiren Cheng ◽  
Huabin Zhang ◽  
Deyan Luan ◽  
Xiong Wen (David) Lou

Conductive metal-organic framework (MOF) materials have been recently considered as effective electrocatalysts. However, they usually suffer from two major drawbacks, poor electrochemical stability and low electrocatalytic activity in bulk form. Here, we have developed a rational strategy to fabricate a promising electrocatalyst composed of a nanoscale conductive copper-based MOF (Cu-MOF) layer fully supported over synergetic iron hydr(oxy)oxide [Fe(OH)x] nanoboxes. Owing to the highly exposed active centers, enhanced charge transfer, and robust hollow nanostructure, the obtained Fe(OH)x@Cu-MOF nanoboxes exhibit superior activity and stability for the electrocatalytic hydrogen evolution reaction (HER). Specifically, it needs an overpotential of 112 mV to reach a current density of 10 mA cm−2 with a small Tafel slope of 76 mV dec−1. X-ray absorption fine structure spectroscopy combined with density functional theory calculations unravels that the highly exposed coordinatively unsaturated Cu1-O2 centers could effectively accelerate the formation of key *H intermediates toward fast HER kinetics.


2003 ◽  
Vol 793 ◽  
Author(s):  
Daniel I Bilc ◽  
S.D. Mahanti ◽  
M.G. Kanatzidis

ABSTRACTComplex quaternary chalcogenides (AgSb)xPbn-2xTen (0<x<n/2) are thought to be narrow band-gap semiconductors which are very good candidates for room and high temperature thermoelectric applications. These systems form in the rock-salt structure similar to the well known two component system PbTe (x=0). In these systems Ag and Sb occupy Pb sites randomly although there is some evidence of short-range order. To gain insights into the electronic structure of these compounds, we have performed electronic structure calculations in AgSbTe2 (x=n/2). These calculations were carried out within ab initio density functional theory (DFT) using full potential linearized augmented plane wave (LAPW) method. The generalized gradient approximation (GGA) was used to treat the exchange and correlation potential. Spinorbit interaction (SOI) was incorporated using a second variational procedure. Since it is difficult to treat disorder in ab initio calculations, we have used several ordered structures for AgSbTe2. All these structures show semimetallic behavior with a pseudogap near the Fermi energy. Te and Sb p orbitals, which are close in energy, hybridize rather strongly indicating a covalent interaction between Te and Sb atoms.


2019 ◽  
Author(s):  
Isaiah R. Speight ◽  
Igor Huskić ◽  
Mihails Arhangelskis ◽  
Hatem M. Titi ◽  
Robin Stein ◽  
...  

Solid-state mechanochemistry revealed a novel polymorph of the mercury(II) imidazolate framework, based on square-grid (sql) topology layers. Reaction monitoring and periodic density functional theory calculations show that the sql-structure is of higher stability than the previously reported three-dimensional structure, with the unexpected stabilization of a lower dimensionality structure explained by contributions of weak interactions, which include short C-H···Hg contacts.


2020 ◽  
Vol 22 (24) ◽  
pp. 13622-13628 ◽  
Author(s):  
Veerachart Paluka ◽  
Thana Maihom ◽  
Michael Probst ◽  
Jumras Limtrakul

Dehydrogenation of ethanol to acetaldehyde with nitrous oxide (N2O) on Fe-supported MOF NU-1000 investigated by means of density functional calculations.


2012 ◽  
Vol 624 ◽  
pp. 117-121 ◽  
Author(s):  
Fan Jun Zeng ◽  
Qing Lin Xia

The electronic structure, chemical bonding and elastic properties of Ti3AC2 (A=Al, Si, Sn) were investigated by generalized gradient approximation (GGA) based on density functional theory (DFT). The calculated lattice parameters and equilibrium volumes are in good agreement with the available experimental data. The density of state (DOS) and partial density of states (PDOS) show that the DOS at the Fermi level (EF) is located at the bottom of a valley and originate mainly from the Ti-3d electrons. Population analyses suggest that there are strong covalent bonding in Ti1-C and Ti2-C atoms in Ti3AC2 (A=Al, Si, Sn). Single-crystal elasticity constants were calculated and the polycrystalline elastic modules were estimated according to Voigt, Reuss and Hill’s approximations (VRH). The Young’s modulus Y, Poisson’s ratio ν and BH/GH are also predicted. Results conclude that the hexagonal phase Ti3AC2 (A=Al, Si, Sn) are mechanical stable and behaves in a brittle manner. Polycrystalline elastic anisotropy coefficients AB and AG are also derived from polycrystalline bulk modulus B and shear modulus G.


2020 ◽  
Vol 17 (7) ◽  
pp. 2890-2896
Author(s):  
Yanhong Dong ◽  
Ning-Ning Wei ◽  
Liguo Gao ◽  
Juanyuan Hao ◽  
Dan Vasilescu ◽  
...  

The sensing mechanism of luminescent metal-organic framework [Zn(3-tzba)(2,2′-bipy)(H2O)] -3H2O for formaldehyde detection was explored by using density functional theory and time-dependent density functional theory methods. Our investigation found that luminescent metal-organic framework [Zn(3-tzba)(2,2′-bipy)(H2O)] • 3H2O is able to interact with formaldehyde through hydrogen bonding to the framework. The luminescent mechanism of the hydrogen-bonded complex is photo-induced electron transfer; while the luminescent mechanism of luminescent metal-organic framework [Zn(3-tzba)(2,2′-bipy)(H2O)]-3H2O is ligand-to-ligand charge transfer. The intermolecu-lar hydrogen bond was found to be stronger in the excited state than that in the ground state by analyzing the geometry nuclear magnetic resonance, binding energy and infrared spectrum in different electronic states. Calculated fluorescence radiative rate coefficient and internal conversion rate coefficient qualitatively indicated a reduced radiative process and an enhanced internal conversion process of the hydrogen-bonded complex. The hydrogen-bonded complex exhibits luminescence weakening or even quenching due to the enhancement of the intermolecular hydrogen bond in the excited state compare with luminescent metal-organic framework [Zn(3-tzba)(2,2′-bipy)(H2O)]-3H2O. The variable luminescence demonstrated the potential of luminescent metal-organic framework [Zn(3-tzba)(2,2′-bipy)(H2O)]-3H2O as luminescent sensor for formaldehyde detection.


2017 ◽  
Vol 204 ◽  
pp. 83-95 ◽  
Author(s):  
Duy Le ◽  
Talat S. Rahman

Metal–organic coordination networks with active metal centers are a promising class of materials for next-generation catalysts. Motivated by experimental observations of the formation of a Pt–Dipyridyl Tetrazine (DT) metal–organic network on the Au(100) surface [D. Skomski et al., J. Am. Chem. Soc., 2014, 136, 9862], we carried out density functional theory based calculations on the same system. In this discussion, we demonstrate that the strong interaction between DT ligands and Pt metal centers makes the network stable and that the Pt centers become positively charged by donating their electrons to the DT ligands, resulting in +2 oxidation states for the Pt centers. We further show that the Au substrate withdraws electrons from and hybridizes with the dz2 orbital of the Pt centers, altering their electronic structure and related properties. Furthermore, we find that the Pt centers can absorb SO2via donor–acceptor interactions, leading to the formation of σ-bonds in which Pt dz2 orbitals act as electron donors, and that the strength of the resultant σ-bond depends on the registry of the Pt centers with the Au(100) surface. Finally, we identify factors, such as the specificity of the ligands and the substrate, and the fullness of the outer shell of the metal centers, that may affect the chemical properties of the metal centers. We suggest modifications (and replacement) of these factors as one of the ways to tune and design metal–organic coordination networks for next-generation catalysts.


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