| During the past two decades,metal-organic frameworks?MOFs?,also known as porous coordination polymers?PCPs?,have received more and more attention.MOFs exhibit a wide variety of potential applications in catalysis,gas storage and separation,luminescence,and magnetic properties,owing to their specific features,such as structural diversity,flexibility and tailorability,high porosity,large surface area.In this context,we are interested in small molecule and ion sensing based on flurorescence and magnetic properties of MOFs.This thesis mainly includes following three parts:1.A 2D zinc?II?metal-organic framework?Zn-MOF-1?formulated as[Zn?L??H2O?]·H2O?1?,?H2L=5-?2-methylpyridin-4-yl?isophthalic acid?with blue fluorescence has been successfully obtained under hydrothermal conditions.Zn-MOF-1 contains microporous parallelogram channels with accessible Lewis-base sites,coordianted water molecules and uncoordinated carboxylate,which are easy to anchor and recognise varios analytes.The fluoresence investigations are demostrated that the blue-light-emitting behaviour of Zn-MOF-1 possesses excellent water and p H stability.More importantly,it is the first reported recyclable multi-responsive Zn-MOF fluorescence sensor towards for Cr?III?,Cr?VI?(CrO42-/Cr2O72-)ions and 4-NP?4-nitrophenol?simultaneously with high selectivity,sensitivity and low detection limits in aqueous solution through fluorescence quenching.2.A 2D zinc?II?metal-organic framework?Zn-MOF-2?formulated as[Zn2?L?2?TPA?]·2H2O,?L=4-?tetrazol-5-yl?phenyl-4,2':6',4''-terpyridine,TPA=terephthalic acid?has been successfully obtained under solvothermal conditions.Zn-MOF-2 shows a new 2D double-layered honeycomb structure constructed by Zn2+ions,an unexplored ligand L and TPA,with uncoordinated nitrogen atoms?from pyridine rings and tetrazol rings?of L and the uncoordinated carboxylate oxygen atoms of TPA,which are easy to form hydrogen bonding with analytes.The fluorescence investigations exhibits that Zn-MOF-2 emits a stromg blue luminescence,which can be assigned to ligand-centred emission.More importantly,it is the first reported Zn-MOF fluorescence sensor focusing on the organochlorine pesticides sensing,which shows highly selectively sensing only towards for2,6-dichloro-4-nitroaniline,with high sensitivity,recyclability and low detection limits in methanol solution through fluorescence quenching.Furthermore,the mechanism of Zn-MOF-2 selectively sensing 2,6-dichloro-4-nitroaniline can mainly be attributed to the absorption of the analytes for the excitation and/or emission light of Zn-MOF-2.3.Five coordination polymers based on pyridine-tricarboxylate ligands formulated as[Co?H3L1??H2O?2]?1?,[Co3?H3L1??H2O?8]·4?H2O??2?,[Mn3?H3L2?2?44'-bpy?2?H2O?2]?3?,[Zn?H3L1?]?4?and[Cd2?H3L1??phen?2?OH?]·2H2O?5??H3L1=4-?2,4-dicarboxylphenyl?picolinic acid,H3L2=5-?3',5'-dicarboxylphenyl?nicotinic acid,phen=1,10-phenanthroline,4,4'-bpy=4,4'-bipyridine?were synthesized under hydrothermal conditions.Compound 1 exhibits a 2D network based on[Co?COO?]n chains in which Co?II?ions are bridged by a single syn-anti carboxylate bridge??-COO?.Compound 2 features a 3D framework based on 2D layers which are further interlinked by Co?II?ions,containing[Co?COO?]n chains which Co?II?ions are also bridged by a single syn-anti carboxylate bridge similar with that in 1.Compound 3 shows a 2D network based on trinuclear[Mn3?COO?6?H2O?2]units in which Mn?II?ions are bridged by the mixed bridges of??-Ocarboxylate??COO?2.Compound 4 exhibits a 2D distorted square-grid network based on[Zn??-Ocarboxylate??COO?]n chains.Compound 5 displays a 2D square-grid network based on tetranuclear[Cd4??3-OH?2?Ocarboxylate?2?COO?2]units in which Cd?II?ions are bridged by the mixed bridges of??3-OH?2??-Ocarboxylate?2.These compounds have been characterized by IR spectra,TGA and powder XRD pattern.Mgnetic studies for compounds 1-3 demostrated that the single carboxylate bridge in 1 and 2 transmits weak antiferromagnetic interactions between Co?II?ions while the mixed bridges of??-Ocarboxylate??COO?2 transmit moderate antiferromagnetic interactions between Mn?II?ions in 3.Compounds 4 and 5 show intense luminescence properties in the solid state at room temperature. |
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