Synthesis And Properties Of Chiral MOFs Thin Films

Chiral Metal-Organic Frameworks?MOFs?have been paid more attention to the great development in the design of structure and synthesis,as well as their potential applications in asymmetric catalysis and chiral separation in recent years.However,a series of problems need to be solved in the practical application.As a form of thin film,Surface Mounted Metal-Organic Frameworks?SURMOFs?can be applied more directly and effectively.In this thesis,Liquid Phase Epitaxy?LPE?method was used to prepare highly oriented and homogeneous chiral SURMOFs thin films Cu₂?Dcam?2_P?P = dabco or bipy?.Homochiral porous Metal-Organic Frameworks ?Dcam?2_P were grown on hydroxyl-MUD self-assembled monolayers?SAMs?and carboxyl-functionalized MHDA SAMs substrates,resulting in homochiral porous thin films along[001]and[110]orientations.The enantioselectivity and adsorption rates in two different oriented homochiral porous thin films were studied by using gas-phase Quartz Crystal Microbalance?QCM?experiment of chiral probe molecules D-/L-methyl lactate.The different mass uptake and time constant showed that the chiral behavior can be obviously influenced by the crystalline orientations.Chiral SURMOFs Cu₂?Dcam?2_P were grown in functionalized?-OH and Poly?L-DOPA??capillary column by Liquid Phase Epitaxy layer-by-layer approach.Gas chromatographic?GC?experiments showed that Cu₂?Dcam?2_P@Poly?L-DOPA?in capillary column had excellent separation efficiency for methyl lactate?P = dabco?and 1-phenylethanol?P = bipy?,respectively,which was effected by the chiral Poly?L-DOPA?functionalized substrate.The experimental result not only indicates that the LPE process might be a promising approach for introducing chiral layers or films as stationary phases for a highly effective separation,but also demonstrates that the chiral Poly?L-DOPA?substrate has the ability for improved enantiomer separation for homochiral SURMOFs thin films.Considering the water instability of chiral SURMOFs thin films,we load the L-DOPA into pores of achiral SURMOFs HKUST-1.Homochiral porous Poly?L-DOPA?thin film were prepared by using HKUST-1 as template.In addition,such a Poly?L-DOPA?thin film exhibited enantioselective adsorption of R-/S-naproxen.And the enantioselectivity of R-/S-naproxen in this Poly?L-DOPA?thin film was calculated to be 32%.In addition,we prepared the azobenzene@HKUST-1 and HKUST-1/SiO₂/Si based composite films.We have applied a modified Liquid Phase Epitaxial pump method for preparation of azobenzene@HKUST-1 with highly oriented and homogeneous composite thin film.When azobenzene was encapsulated into HKUST-1 pores,the obtained thin film not only had a photoisomerization behavior,but also had a temperature-dependent photoluminescent emission.This study can provide a facile strategy for preparing the photochromic thin film materials and open a new dynamic of optical properties for the development of multifunctional optical devices and sensors.We first use MOFs thin film prepared by a Liquid Phase Epitaxial approach to modify the SiO₂ dielectric layer in OFETs.By controlling the LPE cycles?two,three,and four cycles?of SURMOFs HKUST-1 preparation,the charge mobility,threshold voltage,and current on/off ratio can be well-tuned and optimized.The results showed that the performance of the HKUST-1/SiO₂-based OFET was much better than that of the bare SiO₂ based OFET.The performance enhancement of the device is mainly attributed to the highly crystalline,homogeneous,and low-? thin film grown on the SiO₂/Si substrate and the smaller interface trap density in the OFET,which indicates that the SURMOFs HKUST-1 modified dielectric layer is beneficial to the design of a novel architecture of OFETs with tunable and improved performance.