Syntheses,Host-Guest Properties Of Metal-Organic Cages Based On Half-sandwich Rhodium Moieties

Cage is a hot field in scientific research because of unique construction.Cages based on half-sandwich moieties are easy to obtain,stable and has good solubility with other cages.In this text,the syntheses,structures,and host-guest properties of novel metal-organic cages and triply interlocked[2]catenanes are systematically well-studied.These complexes were assembled by three components,including half-sandwich Cp*Rh（Cp*=η⁵-C₅Me₅）fragments as metal nodes,aromatic compounds with multiple pyridyl groups as capping building blocks and oxalate/quinone as bridging building blocks,respectively.The complexes were fully characterized by Nuclear Magnetic Resonance,Mass Spectrometry and Single-Crystal X-Ray Diffraction.The guest molecules withπ-electron conjugation were chosen preferentially,such as anthracene,pyrene and perylene,due to the feature of these metal-organic cages.And we used Nuclear Magnetic Resonance,Ultraviolet-Visible and Photoluminescence（Steady-state fluorescence spectrum）to estimate their host–guest properties.For further study hoet-guest chemistry with different sizes of guests or different widths of bridging building blocks,we chose guests with different size or host with different ridging building blocks to study host–guest properties by Nuclear Magnetic Resonance titration,and calculated binding constants based on Nuclear Magnetic Resonance titration.There are three highlights as following.1.Tetrakis（4-pyridylphenyl）ethylene and oxalate were reacted with Cp*Rh to obtain a new metallacage.Scanning Electron Microscope was performed on the solid samples in methanol.Rod-like blocks are observed clearly when we add some anthracene as guest in solution.We guess four metallacages encapsulating anthracene to form the rod-like block.The process was characterized by Nuclear Magnetic Resonance,Mass Spectrometry and Powder X-Ray Diffraction which could further support this view.The[4+4]cycloaddition reaction could be found when anthracene was encapsulated in the external cavity under ultraviolet light.2.1,3,5-tris（pyridine-4-ylethynyl）benzene and rhodium（III）dinuclear building blocks based on quinonyl derivatives with different widths were chose to construct metallacages or triply interlocked[2]catenanes,which were confirmed by Nuclear Magnetic Resonance,Mass Spectrometry and Single-Crystal X-Ray Diffraction.It was found that with less steric hindrance（narrower organometallic clips）was more likely to obtain catenane.In addition,we found metallacage and catenane can be converted to one another in solution.Catenane is tend to be producted at a high concentration,but it can be converted to metallacage under external stimuli like ultraviolet light in solution.Finally,guests can also be an external stimuli,we chose different host and guest to study host–guest properties by Nuclear Magnetic Resonance titration,calculated binding constants based on Nuclear Magnetic Resonance titration respectively.3、Finding a new way to synthesize one cyanometallate metallacage and two cyanometallate metallacycles base on Cp*Rh and CH₃NO₂.We first proposed a way to obtain cyanometallate compound in room temperature which do not have nitrile in the ingredients.Cyanometallate was characterized by Infrared spectroscopy and Single-Crystal X-Ray Diffraction.We derived the mechanism of the reaction by the crystal products obtained in the different reaction conditions.