Synthesis and photoluminescence properties of pink luminescent heteroleptic Sm(III) complexes; the role of DMSO in transforming the inner coordination sphere and on photophysical properties. Sparkle/RM1 calculation

Experimental and theoretical photophysical study of new synthesized highly asymmetric nona-coordinated trivalent Sm and Eu complexes

The synthesis and characterizations of two new complexes, [Sm(btfa)3Cl-terp] (SmC45H28F9O6N3Cl) and [Eu(btfa)3Cl-terp] (EuC45H28F9O6N3Cl) were done successfully. The complexes have nona-coordinate Sm and Eu centres coordinated to six oxygen atoms of benzoyltrifluoro acetone (btfa) and three nitrogen atoms of chloro-terpyridine (Cl-terp). The ground state geometry of both complexes was optimized using the sparkle model and the shape analysis was carried out using SHAPE v2.1. The detailed photophysical properties of the complexes were studied in solution, solid and 5 % PMMA thin film. The emission spectra of the complexes are devoid of any ligand fluorescence that marks the utilized organic ligands as efficient sensitizers. The decay time and absolute quantum yield of the Sm complex show 12- and 7-fold increase than its precursor [Sm(btfa)3(H2O)2]. The longer decay time of 93 µs is higher than most of the reported trivalent samarium β-diketonate complexes. The Judd-Ofelt intensity parameters, radiative and non-radiative rate constants, intensity ratio, radiative and experimental lifetime, absolute as well as intrinsic quantum yield and sensitization efficiency were calculated and analysed for Eu complex. The decay time, absolute quantum yield and intrinsic quantum yield of [Eu(btfa)3Cl-terp] are 3-, 15- and 3-times larger than precursor, [Eu(btfa)3(H2O)2]. The energy transfer from organic sensitizers to europium ion and the contribution of individual sensitizers along with the luminescence branching ratio of emitting levels of Eu ion were investigated and analysed.

Optimizing white light emission in Dy(iii) complexes: impact of energy transfer from mono and bidentate ligands on luminescence

Complexes of dysprosium(iii) ions with 1,1,1,5,5,5-hexafluoro-2,4-pentanedione featuring various mono and bi-dentate neutral ligands have been prepared and thoroughly investigated. The synthesized complexes exhibit an octa-coordinated environment, achieved by stoichiometrically combining organic ligands and Dy(iii) ions. This octa-coordination environment of Dy(iii) ion was confirmed by FT-IR spectroscopy, thermogravimetry and elemental analysis. Near-white light (NWL) is emitted when complexes were exposed to UV radiation, indicating a significant flow of energy from the sensitizing moieties towards the Dy(iii) ion. This NWL emission might have resulted due to a balance between the intensities corresponding to emission peaks at 480 nm (blue) and 575 nm (yellow) in Dy1-Dy3. Emission spectra recorded at different excitation wavelength were utilized to study the tunability of CIE color coordinates. In addition to their high thermal stability, the complexes display bipolar paramagnetic shifts in their NMR spectra. The 4F9/2 → 6H13/2 transition, contributing ∼62% of the total emission, stands out as a promising candidate for laser amplification due to its dominance in the emission spectra. Additionally, NWL emission observed in a solid Dy(iii) complex opens intriguing possibilities for its application in next-generation white-light emitting devices.

Exploring the role of neutral ligands in modulating the photoluminescence of samarium complexes with 1,1,1,5,5,5-hexafluoro-2,4-pentanedione

Four eight-coordinated luminescent samarium complexes of type [Sm(hfpd)3L2] and [Sm(hfpd)3L'] [where hfpd = 1,1,1,5,5,5-Hexafluoro-2,4-pentanedione L = tri-octyl-phosphine oxide (TOPO) and L' = 1,10-phenanthroline (phen), neocuproine (neoc) and bathocuproine (bathoc) were synthesized via a stoichiometrically controlled approach. This allows for precise control over the stoichiometry of the complexes, leading to reproducible properties. This investigation focuses on understanding the impact of secondary ligands on the luminescent properties of these complexes. Infrared (IR) spectra provided information about the molecular structures, whereas 1H and 13C nuclear magnetic resonance (NMR) spectra confirmed these structural details along with the coordination of ligands to trivalent Sm ion. The UV-vis spectra revealed the molar absorption coefficient and absorption bands associated with the hfpd ligand and photoluminescence (PL) spectroscopy demonstrated intense orange-red emission (648 nm relative to 4G5/2 → 6H9/2) from the complexes. The Commission Internationale de l'Éclairage (CIE) triangles indicated that the complexes emitted warm orange red light with color coordinates (x, y) ranging from (0.62, 0.36) to (0.40, 0.27). The investigation of the band gap as well as color parameters confirms the utility of these complexes in displays and LEDs.

Tuning the Photometric Properties of Ternary Sm3+ Complexes Involving Mixed-Ligands

This research article deals with the synthesis of ternary Sm³⁺ complexes with 6,8-dichlorochromone-3-carboxaldehyde through solution-precipitation method. The photometric properties of resultant complexes were tuned by coordinating N-donor heterocyclic ligands with Sm³⁺ ion. The emission spectra, obtained in the visible region have been studied. Under optical excitation of 370 nm, the complexes displayed characteristic Sm³⁺-centered emission peaks at ~ 563, 600 and 647 nm in solution as well as in powder state. The complexes showed thermal stability up to 175 °C. The complexes delivered quantum yield as high as 7.91% and longest emission lifetime of 0.564 ms. The color coordinates of the complexes, located in deep orange (in solution) and red (in powder) spectral region, matched well with the Society of Motion Picture and Television Engineers and European Broadcasting Union. The properties of complexes have been investigated to a significant extent due to their easy synthesis and potential applications as orange-red light emitter in a wide range of photonic applications such as display devices, OLEDs, dashboards, optical systems.

Towards white light emission from a hybrid thin film of a self-assembled ternary samarium(iii) complex

A new samarium(iii) complex, [Sm(hfaa)₃(Py-Im)], has been prepared and fabricated into thin films which show color tunability from violet to orange depending on the concentration of doping within the film.

Syntheses, crystal structure and photophysical properties of [Sm(dbm)3(impy)] and [Tb(dbm)3(impy)] and their hybrid films

This paper reports the syntheses, crystal structure and photophysical properties of eight-coordinate complexes [Sm(dbm)₃(impy)] and [Tb(dbm)₃(impy)] (dbm is the anion of 1,3-diphenyl-1,3-propanedione and impy is 2-(1H-imidazol-2-yl)pyridine).