Monoporphyrinate neodymium (III) complexes stabilized by tripodal ligand: Synthesis, characterization and luminescence

Excitation of (cyclopentadienyl)tris(dimethylphosphito)cobaltate(I) coordinated monoporphyrinate neodymium (III) complex leads to the photoluminescence in near-infrared region, which is of characteristic for neodymium (III)-centered emission. A series of monoporphyrinate neodymium (III) complexes stabilized by anionic tripodal ligand (cyclopentadienyl) tris(dimethylphosphito)cobaltate(I) were prepared and characterized by IR, ESI-HRMS, UV-Vis and X-ray diffraction studies. Structural analyses revealed that the Nd³⁺ ion was seven-coordinate, surrounded by four nitrogen atoms from the porphyrinate dianion and three oxygen atoms from the anionic tripodal ligand. Photoluminescence studies showed that the porphyrinate dianion acting as a sensitizer absorbed the light and transferred the energy to the Nd³⁺ center, which then allowed the metal ion to emit efficiently at 885 and 1071 nm. The luminescent intensity of the complexes increases when there are strong electronic donating groups on the porphyrin rings but decreases with increasing polarity of the solvents.