Synthesis, characterization, and crystal structure of Ln^III – (1E,2E)-3-(furan-2-yl)-N-(4H-1,2,4-triazol-4-yl)prop-2-en-1-imine

Abstract

New neodymium (1a) and samarium (1 b) complexes with the general formula [Ln^III(NO₃)₃(H₂O)₃L]·L (1) were synthesized based on the previously reported ligand L (L = (1E,2E)-3-(furan-2-yl)-N-(4H-1,2,4-triazol-4-yl)prop-2-en-1-imine) which were investigated by X-ray analysis. Through X-ray studies, it was shown that the Schiff base L coordinates to Ln^III via κN-bonding of one of the triazole ring nitrogen atoms as a monodentate ligand, three κ²OO′-bonded nitrate ions and three κO-bonded water molecules completing the coordination sphere around the Ln^III ion, resulting in a tenfold-coordinated LnNO₉ unit in a distorted bicapped square antiprismatic geometry. The mononuclear complex units [Ln(NO₃)₃(H₂O)₃·L] are linked to the L molecule through intermolecular hydrogen-bonding interactions to form a 2 D polymeric supramolecular architecture. The complexes are neutral and paramagnetic mononuclear complexes, as determined by conductivity and magnetic investigations at room temperature, as well as findings from FT-IR and UV–vis spectroscopy. Finally, thermogravimetric measurements confirm the presence of three water molecules in the coordination sphere. In the visible region, the spectrum of the complex shows typical parity forbidden narrow 4f–4f absorptions originating from the ⁴I_9/2 ground state to the various excited states of Nd^III.

Graphical Abstract

Keywords:

• Synthesis
• spectroscopy
• crystal structure
• lanthanide complexes
• Triazole Schiff base ligand

Acknowledgement

The author thanks the Deanship of Scientific Research at Al-Hussein Bin Talal University in Jordan for supporting this research with Research Project No. 432/2018.

Additional information

Funding

The author thanks the Deanship of Scientific Research at Al-Hussein Bin Talal University in Jordan for supporting this research with Research Project No. 432/2018.