| Recently,complexes synthesized by pyrazole carboxylic acid derivatives have received wide attention not only due to their fascinating structural,but also because of their potential applications in catalysis,fluorescent probes,gas adsorption,supercapacitors and medicine.In additional,N–substituted heterocyclic pyrazole carboxylic acid derivatives contain a large number of N–and O–heteroatoms,which can show a variety of coordination modes.Therefore,complexes with novel structures and diverse properties can be obtained by coordination with different metal ions.Based on the background,14 novel complexes are designed and constructed with three N–substituted heterocyclic pyrazole carboxylic acid ligands.The structures of the complexes were determined by X–ray single crystal diffraction,and the photoelectric properties of the synthesized complexes were studied.The detail contents are as following:(1)Taken 3–(pyrazin–2–yl)–1H–pyrazole–5–carboxylic acid(H2L1)as ligand to act with metal solts resulting nine complexes with different structures:[Zn3(?–L1)2Cl2(H2O)4]n(1),{[Zn4(?–L1)4(H2O)4)]·6H2O}n(2),{[Ni(?–L1)(H2O)]·H2O}n(3),{[Co Co0.5Co0.5(?–L1)2(H2O)3]·3H2O}n(4),{[Cd(?–HL1)(?–I)(H2O)]·H2O}n(5),[Pb(?–HL1)Cl]n(6),[Cu2(L1)2](7),[Cd(HL1)2(H2O)3](8),[Cd(HL1)2(H2O)2]·H2O(9).While complex 1 and 6 show infinite 1D chain structures,2–5 are 2D structures,7 shows a diunclear and 8,9 are mononuclear structures.The fluorescence test of complex 1 shows that the fluorescence intensity of complex 1 is about 8 times stronger then that of free ligand,which is suitable for the study of fluorescence sensing of analyte.The luminescent sensing study shows that polymer 1 is a promising luminescent sensor for the detection of Cu2+?Co2+and Fe3+via drastic luminescence quenching in aqueous solution with high efficiency.The quenching constants Ksv for Cu2+,Co2+and Fe3+ions are 6.35×103M–1,8.70×103 M–1 and 1.62×104 M–1 respectively.Furthermore,the electrochemical luminescence(ECL)properties of 1-7 show highly intensity and high stability.For 1–7,the maximum ECL intensities are about 1095,662,1639,654,1029,1771 and 1207 a.u.,respectively.(2)Taken 3–(pyridin–2–yl)–1H–pyrazole–5–carboxylic acid(H2L2)as directed ligand,four complexes{[Pb2(?–L2)2]·H2O}n(10),[Pb(?–HL2)Cl]n(11),[Cu2(L2)2(H2O)2]·H2O(12),[Zn(HL2)2(H2O)2]·3H2O(13)have been synthesized under solvothermal condition,where 10 and 11 are 1D infinite chain structures,12 is dinuclear and 13 is mononuclear.Taken 3–(pyridin–4–yl)–1H–pyrazole–5–carboxylic acid(H2L3)as directed ligand and construced a 3D MOFs of[Cd(?–L3)]n(14).The fluorescence detection showed that 10 demonstrates luminescence response toward Fe3+ions in alcohol solution with the detection limit of 5.18×10–7 M,indicating 10 is a promising luminescent chemosensor to selectively and sensitively probe Fe3+ions.In addition,complexes 10–12 and 14 exhibit high intense ECL,the maximum ECL intensities are about 2024,526,665 and 1069 a.u.,respectively and after nine circulations the ECL intensity still remains stable,which can be a useful guide for the construct of new polymers ECL materials. |
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