| Metal organic salts(MOSs)are hybrid metal organic materials,which connected by organic cations and metal anions through a network constituted by weak hydrogen bonds in non-covalent interactions.They have potential value of research in fluorescent probes,magnetic materials,and solid-gas adsorption.Nitrogen heterocyclic carbene(NHC)is a kind of organic ligands with special topological structure.The nitrogen heterocyclic carbene metal organic salts formed with transition metals are used in catalysis,ionic liquid,optical materials and other aspects.However,the synthesis of these compounds is mostly based on the solvent method.In order to reduce the use of toxic reagents,it is particularly important to study the green synthetic route.Mechanochemistry,as a synthetic method in solid-state reactions,has attracted widespread attention due to its advantages such as less solvent usage,simple operation,time-saving and high-efficiency.In this thesis,mechanical synthesis was used as the main method to synthesize imidazole nitrogen heterocyclic carbene ligands L1·2Cl,L2·2Cl,L3·2Br,L4·2Br,L5·Cl with different chain lengths using a planetary ball mill(pbm)under solvent-free conditions,and their structures were characterized by nuclear magnetic1H NMR.Using the above ligands and metal halide MX2(M=Zn,Co,Cu;X=Cl,Br)as raw materials,a series NHC metal organic salts were prepared by the method of liquid assisted grinding:[H2L1]2+·[Cu Cl4]2-(1),[H2L1]2+·[Zn Cl4]2-(2),[H2L1]2+·[Co Cl4]2-(3),[H2L2]2+·[Zn Cl4]2-(4),[H2L3]2+·[Co Br4]2-(7),[H2L5]2+·[Cu Cl4]2-(10),[H2L2]2+·[Co Cl4]2-(5),[H2L4]2+·[Zn Br4]2-(8),[H2L5]2+·[Zn Cl4]2-(11),[H2L3]2+·[Zn Br4]2-(6),[H2L4]2+·[Co Br4]2-(9),[H2L5]2+·[Co Cl4]2-(12)and pyridine nitrogen coordinated complexes:[Zn(L5)Cl3](13)and[Co(L5)Cl3](14).The structure of above products were characterized and analyzed by infrared spectroscopy,single crystal diffraction and powder diffraction.Taking the above-mentioned metal organic salts and complexes as objects,through their solid-gas reaction research in acid gas,the following conclusions are obtained:2-5 containing chloride ions change the equilibrium anion in the structure by adsorbing HBr respectively,thereby It is converted into 6-9 containing bromide ions,which realizes the solid-state conversion between metal organic salts;13 and14 connected by covalent bonds break their own nitrogen-metal bonds through adsorption of HCl respectively,forming organic cations and metal anions.Relying on the recombination of hydrogen bonds in non-covalent interactions into 11 and 12,the conversion of complexes to salts under solid state conditions is further realized. |
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