Synthesis And Applicants Of Nucleotides/Lanthanides Metal-organic Coordination Polymers

Metal organic coordination polymers（MOCPs）,consisting of metal ions as nodes and organic ligands as linkers.Coordination polymer have attracted much attention because of their potential application in catalysis,sensing,drug delivery,and gas adsorption.Here,we report the synthesis of a type of nucleotide/lanthanide metal organic coordination polymer by the self-assembly of a nucleotide,a lanthanide ion.Then,we explored and studied their properties and applications,the main research work is as follow:（1）Adenosine monophosphate（AMP）and lanthanides form two types of coordination materials:the lighter lanthanides from La³⁺to Tb³⁺form nanoparticles,while the rest heavier ones initially form nanoparticles but later spontaneously transform to hydrogels.This slow sol-to-gel transition is accompanied with heat release as indicated by isothermal titration calorimetry（ITC）.The transition is also accompanied with a morphology change from nanoparticles to nanofibers as indicated by TEM.These gels are insensitive to ionic strength or temperature with excellent stability.Gelation is unique to AMP since other nucleotides or other adenine derivatives only yield nanoparticles or soluble products.Entrapment of guest molecules such as glucose oxidase is also explored,where the hydrogels allow better enzyme activity and stability compared to nanoparticles.（2）We explored mixed nucleotides and studied their DNA adsorption property by using fluorescently labeled oligonucleotides.Adenosine monophosphate（AMP）and guanosine monophosphate（GMP）formed negatively charged coordination polymers nanoparticles with most lanthanides,and thus salt was required to adsorb negatively charged DNA.DNA adsorption was faster and reached a higher capacity with lighter lanthanides.Desorption of pre-adsorbed DNA by inorganic phosphate,urea,proteins,surfactants and competing DNA was respectively carried out.The results suggested the importance of DNA phosphate backbone,while hydrogen bonding and DNA bases also contributed to adsorption.The AMP CPs adsorbed DNA more strongly than the GMP ones,and by using mixtures of AMP and GMP,continuous tuning of DNA adsorption affinity was achieved.Such CPs were also used as a sensor for DNA detection based on the different affinities of single-and double-stranded DNA,and a detection limit of 0.9 nM target DNA was achieved.Instead of tuning DNA adsorption by varying the length and sequence of DNA,the composition of coordination polymers can also be controlled to achieve this goal.（3）We report the synthesis of a luminescent sensing coordination polymer by the self-assembly of AMP,Terbium（Ⅲ）ion and a functional ligand 1,10-phenanthroline.Due to the incorporation of1,10-phenanthroline as both a sensitizer and a recognition unit,the luminescence of this coordination polymer was enhanced,and exhibited excellent selectivity and sensitivity to the iron（II）ions.This coordination polymer containing Terbium（Ⅲ）ions was applied to detect iron（II）ions in human serum.