Enhanced Emission of Nd3+ in Liquid Systems: Formation of Symmetrical Rigid Shells of Tightly Solvated DMSO Molecules and Weakly Coordinated Low-Vibrational β-Diketonato Ligands

Abstract

Coordination structures of neodymium(III) complexes with some β-diketones were investigated in terms of their correlations with emission efficiency in deuterated dimethylsulfoxide (DMSO-d6). The analysis of UV-vis spectra, 13C NMR, electrospray mass spectrometry (ES-MS) spectra, XANES and EXAFS analysis of tris(hexafluoroacetylacetonato)neodymium(III) complex, [Nd(hfa-H)3(H2O)2], and tris[bis(perfluorooctanoyl)methanato]neodymium(III), [Nd(pom-H)3], in DMSO indicated that the deuterated tris(hexafluoroacetylacetonato)neodymium(III), Nd(hfa-D)3, and deuterated tris[bis(perfluorooctanoyl)methanato]neodymium(III), Nd(pom-D)3, in DMSO-d6 should have a symmetrical, rigid and bulky shell composed of six inner-coordinating DMSO molecules and three weakly coordinating hfa-D and pom-D molecules. The improvement in the emission efficiency of the neodymium complexes with the low vibrational and weakly coordinating β-diketonates in DMSO-d6 was ascribed to their symmetrical rigid coordination structures, which should suppress radiationless transition via vibrational excitation and energy migration in the fluid system.

Effective photosensitized, electrosensitized, and mechanosensitized luminescence of lanthanide complexes

“…The emission quantum efficiency of a lanthanide(III) complex is also dependent on its coordination geometry and vibrational structure. We reported the importance of the radiative k r constant depending on the lanthanide(III) coordination geometry [176][177][178][179][180][181][182][183][184][185] and the non-radiative k nr constant depending on the vibrational structure of the organic ligands [186][187][188][189][190][191][192][193][194][195][196][197] . Control of the k r and k nr constants in an excited lanthanide (III) complex is also important for the development of a strong luminescent lanthanide(III) complex.…”

Synthesis, crystal structure, and optical properties of a novel rare-earth complex Nd(C2F5COO)3 · Phen

“…To estimate the strength of crystal field in the liquid system, we calculated the Judd-Ofelt parameter X 2 (0.98 9 10 -20 cm 2 ) of Nd(III) ions. Symmetrical crystal fields of the Nd(III) ions lead to significant decrease in values of the parameter X 2 because of domination of magnetic dipole transition along with decrease of electric dipole transition [24]. The X 2 of the Fig.…”

Synthesis, structure and properties of intercalation compounds containing perfluoroalkyl groups

“…This increase of emission can be ascribed to the perfluoroalky chains surrounding RhB molecules. Considering the previous report on the enhanced emission from neodymium complexes using perfluorinated ligand [31], the lower radiationless quenching by low vibrational C-F bonds would be responsible for the increase of fluorescence.…”