Dft Study On The Modified New Organic Frameworks

Metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs), as the novel porous materials, offer various applications in the fields of gas adsorption and separation, catalysis, optics, electronics. Therefore, it is very necessary to carry out their fundamental theory research.Utilizing first-principles density functional theory calculations, we identified the weak adhesion of metal clusters (for example Cu and Au) on pristine MOF-5, IRMOF-3, IRMOF-3-OH and IRMOF-3-SH, revealing that metal clusters may be unable to stably exist in the pores of MOFs. Furthermore, upon removing the hydrogen of-NH2,-SH and-OH functional groups, the adsorption energy between metal cluster and functionalized MOFs increased, which can be mainly ascribed to enhanced chemical interactions. Meanwhile, these metal clusters became cationic as a result of the formation of metal-O, S or N adhesion bonds. Hence, our study may provide a candidate approach to deposit metal clusters into the pore of MOFs.Meanwhile, we systematically investigate the effect of different directional electric field on the band gap of MPc-COFs (M=Ni、Zn、Pt、 Cu、Pd) based on DFT calculations. Specifically, it is obtained that electric field along [100] can effectively affect the electronic structure of MPc-COFs. When the electric field is strong enough, the band gap of the MPc-COFs shifts down to the conductor range. Moreover, both electronic structure and frontier orbits, coupled with Miilliken charge population, suggest that the polarization of charge density along [100] direction induces some degenerate orbits to split, leading to the decrease of band gap.