Solid State Synthesis And Transformation Between Metal Salts And Coordination Complexes Based On 2-(cyclohexylaminomethyl)pyridine

Molecular recognition and self-assembly are two important methods for the study of supramolecular chemistry.Molecular recognition has been widely used as ion separation,inclusion of guest molecules,adsorption of gas molecules,catalytic reactions,etc.Functional supramolecular aggregates by self-assembled also show potential applications in light and electromagnetic fields.The formation of complexes through coordination bonds or noncovalent interactions to form supramolecular aggregates formed by metal or metal ions and organic ligands has been a very active research in the chemistry.The studies on novel,controllable and efficient synthesis methods for supramolecular complexes or coordination complexes combined with new structures and special functions are the research topics that many chemists are currently working on.In this paper,solid state chemistry was used to synthesize metal organic salts and their coordination complexes,to achieve the green preparation.The details are as follows:In this paper,the organic ligand 2-?cyclohexylaminomethyl?pyridine?L?containing N bidentate is synthesized.Combining protonated ligand to metal chloride by hydrochloric acid,a series of metal organic salts[H₂L]²⁺[MCl₄]^2-and their coordination complexes L:MCl₂,L:MCl₂·Solvent,?Solvent=CH₃CN,DMF?were prepared by solution volatilization method and micro-liquid assisted grinding method,respectively.The above structures were characterized and analyzed by IR,NMR,X-powder diffraction and single crystal diffraction.The experiment results show that the metal organic salts can produce corresponding coordination complexes by direclty grinding with alkali in the solid state,thus realizing the green synthesis.At the same time,coordination complexes can also change back to metal organic salts upon absorbing HCl gas.Therefore,the process is a reversible transformation between metal organic salts and coordination complexes.In addition,the thermal stability and solid state fluorescence of the prepared metalorganicsaltsandtheircoordinationcomplexeswerestudied.Thermogravimetric analysis shows that the the metal organic salts would slowly dehydrochlorinate during the heating process,while their corresponding coordination complexes are more stable than the salts.Further heating,the framework of salts or coordination complexes would be broken,combined with the oxidative decomposition.The solid fluorescence study shows that the fluorescence intensity of crystals varies greatly,mainly due to the impact of different metal ions and the spatial packing arrangement of crystals.