Preparation And Application Of Organic Functional Materials Based On Pillarenes

Pillararenes(pillarenes for short) as a relatively new class of synthetic macrocycles have seen a tremendous boost in molecular recognition, self-assembly, sensing and detection, biological applications, optical materials, etc. With the high-speed development of economy and the continuous improvement of living standards, attention has been focused on solving problems of energy storage, ecological environment, and treatment of diseases, which largely depends on the development of new materials and technology. Therefore, this paper closely focuses on pillarenes, using organic porous energy storage materials and supramolecular nanovalves as the function orientation, combining the unique cavity properties and versatile functionality, developing and establishing new method for constructing pillarene-based organic functional materials, builting new platform for controllable preparing macrocycle-based functional organic materials, solving the problem of energy storage, gas adsorption and separation, targeted drug delivery and controlled release, etc., providing new ideas and strategies for solving important scientific problems which are closely related to human social life.Firstly, we employed a new strategy for the preparation of the DMP5 in high yield by adjusting reaction time, reaction temperature, molar ratio and solvent volume. For the first time, we obtained the complexes crystals of DMP5 with highly volatile solvents, acetonitrile, dichloromethane, ethyl acetate, acetone, which indicated DMP5 included guest molecules with 1:1 stoichiometry. NMR titrations indicate that the association constants of these complexes increase in the order of hexane < acetone < ethyl acetate < dichloromethane < acetonitrile. Isothermal titration calorimetry(ITC) data indicate that the complexation is spontaneous and primarily driven by enthalpy changes, hydrogen bonding, size-fit and shape-fit effects also play important roles in the high selectivity recognition. Our current study is envisioned to bring more insights into the host-guest chemistry of pillarenes upon binding with small organic molecules, such as solvent molecules, and help understand further on how solvent molecules will influence the host-guest binding behaviour of pillarenes towards many other interesting guest compounds, provide the opportunity for pillarene-based selective adsorption and separation.Secondly, we have successfully obtained low-density pillarene-based SOFs, exceptionally high C2H2 uptake(up to 0.12 g cm-3, STP), and excellent selectivity of C2H2 and CO2 over other gases(up to 3733). For the first time, we observed P6 networks with 3D uninodal 6-connected pcu alpha-Po primitive cubic(41263) topology, in which the backbone of each P6 molecule adopts unprecedented C2 symmetric chair confirmation with neighboring phenylene groups arranged in an orthogonal fashion. This is in great contrast to nanotube-like P6-SOF-1, which is composed of highly symmetric(D6h) pillar-shaped P6 rings. P5-SOF with uninodal 7-connected SP 2-periodic net(3641352) was also obtained. Overall, the collaborative effects of pore size, shape and connectivity together with chemical environment in host frameworks make these pillarene-SOFs promising candidates as highly selective porous materials for gas storage, separation and purification. Such development will pave a new avenue to explore the great potential of synthetic macrocycle-based SOFs in gas-storage and gas-separation applications.At last, spurred by recent advances in materials chemistry and drug delivery, a new stimuli-responsive theranostic hybrid platform, based on mechanized monodisperse nano metal-organic frameworks(NMOFs) gated by carboxylatopillar[5]arene(CP5) switches with bio-friendly p H-triggered cargo release capability, has been first constructed. Given the need to develop scaffolds for advanced therapies that can improve features of conventional systems, herein, we first provide a new combination therapy principle. Mechanized Zr-MOFs with multi-stimuli responsive supramolecular gatekeepers that combine thermotherapy with chemical(low p H in osteoclasts and tumour cells) and biochemical triggers(high Ca2+ concentration caused by osteolysis and bone resorption, high Zn2+ caused central nervous system diseases) were designed. Our motivation is to find better central nervous system diseases and bone cancer therapies and ameliorate the adverse side effects in traditional therapy. The new strategy offers important prospects for the potential central nervous system diseases and bone cancer therapies:(1) Because of the high concentration of Zn2+/Ca2+ or lower p H around lesions, drugs can be released on the targeted sites which minimize side effects.(2) The concentration that induces cargo release should be fine-tuned according to the varied Zn2+/Ca2+ concentration and p H in patients. Our mechanized MOFs with supramolecular gates can achieve a better therapeutic effect by accounting for the different characteristics of patients.(3) These nanocontainers can not only transport the desired drugs but also decrease adverse side effects and tune the p H and Zn2+/Ca2+ concentration in patient body.(4) Hyperthermia has been widely used for cancer treatment and palliation of the painful bone metastases. Meanwhile, with elevated temperature, supramolecular host-guest interactions within the gating entities are weakened followed by the disassociation of rings from MOF surfaces to unblock the pores and the release of the stored cargo molecules.(5) The Nano MOFs can be tunned according to the requirements.This on-command drug delivery system exhibits large pore sizes for drug encapsulation, excellent biodegradability and biocompatibility, extremely low cytotoxicity and premature drug release, and superior multiple-stimuli responsiveness, opening a new avenue in targeted drug delivery and controlled release of therapeutic agents.