Abstract:

The o-nitro-benzoic acid(C₇H₅O₄N) and N,N-dimethylformamide(DMF) coordinate with La(Ⅲ) to form a dinuclear complex The onitrobenzoic acid(C₇H₅O₄N) and N,Ndimethylformamide(DMF) coordinate with La(Ⅲ) to form a dinuclear complex The onitrobenzoic acid(C7H5O4N) and N,Ndimethylformamide(DMF) coordinate with La(Ⅲ) to form a dinuclear complex La［oC6H4(NO2)(CO2)］3·(DMF)2}2. The complex resides on an inversion center. The structure of the complex is characterized by IR, ¹H NMR, ¹³C NMR, UV and fluorescent emission spectra. The results show that the complex crystallizes in a triclinic system, space group P1, cell parameter a=1.902(2) nm, b=1.245 0(2) nm, c=1.298 7(2) nm, α=64555(2)°, β=66348(2)°, γ=71.920(2)°, V=1.569 5(5) nm3,  Dc=1.658 Mg/m³, Z=2, μ=1.437 mm^-1, F(000)=784. In the complex, two La(Ⅲ) are bridged by four onitrobenzoic acids liganding with their carboxyl. The coordination number of La(Ⅲ) is nine and the coordinated atoms are all oxygen from the carboxyl and carbonyl. Nine oxygen atoms(seven from a carboxyl of onitrobenzoic acid and two from DMF molecule) occupy the nine coordination sites around La(Ⅲ), respectively. Hydrogen bonds and aromatic π…π stacking interactions assemble the title complex into a three dimensional network. Luminescence measurement shows that the complex emits fluorescence. . The complex resides on an inversion center. The structure of the complex is characterized by IR, ¹H NMR, ¹³C NMR, UV and fluorescent emission spectra. The results show that the complex crystallizes in a triclinic system, space group P1, cell parameter a=1.902(2) nm, b=1.245 0(2) nm, c=1.298 7(2) nm, α=64.555(2)°, β=66.348(2)°, γ=71.920(2)°, V=1.569 5(5) nm³,  Dc=1.658 Mg/m³, Z=2, μ=1.437 mm^-1, F(000)=784. In the complex, two La(Ⅲ) are bridged by four o-nitro-benzoic acids liganding with their carboxyl. The coordination number of La(Ⅲ) is nine and the coordinated atoms are all oxygen from the carboxyl and carbonyl. Nine oxygen atoms(seven from a carboxyl of o-nitro-benzoic acid and two from DMF molecule) occupy the nine coordination sites around La(Ⅲ), respectively. Hydrogen bonds and aromatic π…π stacking interactions assemble the title complex into a three dimensional network. Luminescence measurement shows that the complex emits fluorescence. The complex resides on an inversion center. The structure of the complex is characterized by IR, ¹H NMR, ¹³C NMR, UV and fluorescent emission spectra. The results show that the complex crystallizes in a triclinic system, space group P1, cell parameter a=1.902(2) nm, b=1.245 0(2) nm, c=1.298 7(2) nm, α=64.555(2)°, β=66.348(2)°, γ=71.920(2)°, V=1.569 5(5) nm3,  Dc=1.658 Mg/m3, Z=2, μ=1.437 mm-1, F(000)=784. In the complex, two La(Ⅲ) are bridged by four o-nitro-benzoic acids liganding with their carboxyl. The coordination number of La(Ⅲ) is nine and the coordinated atoms are all oxygen from the carboxyl and carbonyl. Nine oxygen atoms(seven from a carboxyl of o-nitro-benzoic acid and two from DMF molecule) occupy the nine coordination sites around La(Ⅲ), respectively. Hydrogen bonds and aromatic π…π stacking interactions assemble the title complex into a three dimensional network. Luminescence measurement shows that the complex emits fluorescence.

Key words: Lanthanide complex; Synthesis; Crystal structure; Fluorescence