Study On The Construction And Properties Of Polydentate Cationic Ligand Complexes With Hexamethylenetetramine And Its Derivatives

In this article two 2-3D metal-organic frameworks were synthesized by self-assembly of copper（I）halide and hexamethylenetetramine（L0）ligand.[L0][Cu₄I₅][H₂O]₅[NH₄]}_n（1）and{L0][Cu₃Br₃][H₂O]}_n（2）.Compound 1 is a two-dimensional metal-organic framework composed of a pyramidal Cu₄I₅ cluster and hexamethylenetetramine.In which L0 bridge Cu-clusters form a two-dimensional（4,4）-connected net with point symbol of（4⁴·6²）（4⁴·6²）.Compound 2 is a chiral three-dimensional metal-organic framework material produced by spontaneous crystallization of an achiral precursor.The two compounds were characterized by a series of analysis such as infrared,elemental analysis,CD spectra and powder X-ray diffraction.Both of them exhibit unexpected stability under a wide range of conditions of acid and base.In addition,the fluorescence intensity changes regularly under acid-base conditions.Compounds 1 and 2 also display the selective adsorption and a significant degradation effect on organic dye methylene blue（MB）.In addition,the fluorescence study indicated that compound 2 could be used as a sensor to detectComplexes synthesized with benzyl substituted hexamethylenetetramine as polydentate ligands,and the properties of compounds were studied.Four different cations were synthesized with hexamethylenetetramine and benzyl bromide（L1）,o-dibromobenzyl（L2）,m-dibromobenzyl（L3）and 1,4-dibromobutane（L4）.10compounds were synthesized from four different cations.Where{[L1][Cu₂（SCN）₃]}_n（3）,{[L1][Cu₂I₃]}_n（4）（L1=N-benzylhexamethyltetraamine bromide）.Owing to their unique structural and the desirable composition,the as-prepared organic-inorganic hybrid materials exhibit high efficiency and excellent cycling stability for degradation of tetracycline（TC）under visible light irradiation.In addition,the effect factors for photocatalysis such as catalyst dosage,temperature,and p H were also investigated.The possible mechanism studied shows that degradation process of TC.This work may shed light on preparing new organic-inorganic hybrid materials with promising photocatalysis performance for water purification.{[L1]₂[Cd I₄]}（5）,{[L1]₂[Pb₂I₆]}_n（6）,{[L1]₂[β-Mo₈O₂₆][H₃O]₂[H₂O]₃}（7）,{[L2][Cd I₄][CH₃CN]}（8）,{[L2][Pb I₄]}_n（9）,{[L3][Cd I₄][CH₃CN][H₂O]}（10）,{[L3₁][Al Mo₆（OH）₇O₁₇][H₂O]₄}（11）,{[L4][Cu₂S₄C₄N₄]}_n（12）.They were systematically characterized.Both compound15 and compound 16 have a mononuclear structure,the anion of compound 14 has a binuclear structure,and compound 13 has a one-dimensional anionic structure.Adsorption dye methylene blue（MB）experiments were performed on compounds5-16.Compound 7 can also capture methylene blue dyes at very low concentrations.The effects of the amount of adsorbent,temperature,and acid and alkali on the adsorption of organic dyes were systematically studied.The adsorption behavior of compound 7 is in good agreement with the pseudo-second-order kinetic model.The maximum adsorption capacity of methylene blue（MB）(951 mg·g^-1)is higher than the most reported adsorbent.More importantly,compound 7 still had a higher adsorption effect after 3 cycles.These results indicate that the compound treatment wastewater has potential application prospects.