Probing the Chemical Bonding and Electron Structure of the Benzoate model for Fe-MoF-5
- PDF / 758,226 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 90 Downloads / 170 Views
Probing the Chemical Bonding and Electron Structure of the Benzoate model for Fe-MoF-5 Jun Zhang1,2, Xiaohong Zheng1,Chunsheng Liu1 and Zhi Zeng1,2,3,* 1 Key Laboratory of Materials Physics, Institute of Solid State Physics, CAS, Hefei 230031, P.R. China 2 Department of Physics, University of Science and Technology of China, Hefei, 230026, China 3 Kavli Institute for Theoretical Physics China, CAS, Beijing 100190, China ABSTRACT Using 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, HC 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. INTRODUCTION Metal-organic-frameworks have attracted a great deal of attention because of their promising applications in a variety of research fields such as gas storage, heterogeneous catalysis, nonlinear optics, host-guest induced separation, drug delivery, etc. [1-5]. Within the huge MOF family of structures, the most well known example is probably MOF-5 [6], which is the first member of a series of isoreticular MOFs with oxide-centered Zn4O tetrahedral as nodes linked by organic molecules. Many efforts have been devoted to exchange Zinc with other divalent metals to improve the gravimetric gas storage capacity or produce specific catalytic and magnetic properties [7-10]. However, hitherto rare reports claimed that similar MOF-5 structures with other metal center than Zn were synthesized. Theoretically, we could predict the binding property of the metal atom and its neighboring atoms when the Zn atom is replaced by other metal. Therefore in this paper, the electronic structure and binding nature of the central metal atom and the surrounding atoms in the case of Zn being replaced by Fe in MOF-5 structure are studied. The bonding interaction between the constituents is important to understand the chemical and physical properties of MOF-5, and may help to improve its applications in gas storage, magnetism, and optoelectronics. Additionally, it will guide the understanding of other MOFs. Moreover, MOF-5 has a highly symmetric periodic structure with 106 atoms per primitive cell. To probe the interaction between the metal atom of the vertex and its neighboring atoms, there is no need to concern the whole primitive cell. Instead, we choose a model that contains the atoms near the vertex which effectively reflects the local environment of the crystal. This method has been widely used [11-13] and proved to be feasible in the simulation of the local environment in the extensive crystalline structure. Among them, the tetranuclear benzoate
OM4(CO2Ph)6 (M: metal) is a good model system, and in fact OZn
Data Loading...
