Synthesis, spectroscopic properties, crystal structure and Hirshfeld surface analysis of Pr(III), Sm(III), Gd(III), Dy(III), and Ho(III) coordination compounds with Schiff base ligand derived from 4-aminoantipyrine

Abstract

Under reflux condition five new lanthanide coordination compounds, [Pr(L)2(NO3)3(CH3OH)] (1), [Sm(L)2(NO3)3(CH3OH)] (2), [Gd(L)2(NO3)3(CH3OH)] (3), [Dy(L)2(NO3)3(CH3OH)] (4) and [Ho(L)2(NO3)3(CH3OH)] (5), were synthesized in methanol where L is the Schiff base ligand prepared from the reaction of 4-aminoantipyrine and 5-bromosalicylaldehyde. Elemental analysis, FT-IR, UV/Vis and photoluminescence spectroscopic methods and single crystal X-ray analysis were used to investigate the crystal structure and properties of the synthesized compounds. Using X-ray analysis, it was found that all crystals are isomorphous and the Ln ion (Ln = Pr, Sm, Gd, Dy and Ho) in all of the synthesized compounds is nine-coordinated and the geometry around them is slightly distorted tricapped trigonal prism. Six oxygen atoms are coordinated to the central lanthanide atom by three nitrate groups, one oxygen atom from the methanol group and two oxygen atoms of the Schiff base ligand (L) which create the LnO9 coordination environment. Intermolecular interactions and the distribution of these interactions in all of these crystals were calculated by Hirshfeld surface analysis using Crystal Explorer 17.5 software. The emission spectrum of these compounds was recorded and the obtained results showed that the intensity of peaks has differences and the emission spectrum of the complexes changes by changing the lanthanide ions.