Photophysical studies of coordination polymers and composites based on heterometallic lanthanide succinate

• Published in: Journal of molecular structure Vol. 1207; p. 127829
• Main Authors: Santos, Guilherme C., de Oliveira, Carlos A.F., da Silva, Fausthon F., Alves, Severino
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.05.2020
• Subjects: Carbonaceous materials; Composites; Coordination polymers; Coordination polymers; Carbonaceous materials; Composites
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2020.127829

This work reports the synthesis and characterization of heterometallic Tb/Eu lanthanide-succinate coordination polymers (CPs) under hydrothermal conditions. Compounds were obtained inserting different quantities of Eu3+ ions into the terbium succinate structure, named here xEuyTbSuc (x and y are the percentage of the respective lanthanide ions). Composites with these heterometallic CPs and activated carbon (CP@AC, AC = activated carbon) were obtained using one-pot hydrothermal reactions. Bimetallic CPs with or without presence of AC crystallize in monoclinic system, isostructural to [Ln2(Suc)3(H2O)2]•0.5H2O (Ln = Eu or Tb), already described in the literature, confirmed by X-ray powder diffraction (XRPD) data. Scanning electron microscopy (SEM) images show the CP crystals inside the carbon pores. Luminescence spectroscopy measurements (excitation, emission and lifetime) were conducted to explore photophysical properties of these new materials. Lifetime data indicates all Eu3+ ions are in the same chemical environment. Even at low concentration (1%), Eu3+ transitions (5D0→7FJ (J = 0–4)) were observed in the emission spectrum, along transitions related to the Tb3+ cations (5D4→7FJ (J = 6–3)), due to the metal-to-metal charge transfer (MMCT) between the lanthanide ions. Similar results are found in the composites. Increasing the Eu3+ concentration, a more intense MMCT process took place, suppressing the terbium emission. [Display omitted] •Lanthanide succinates were obtained with different molar ratios of Eu and Tb ions.•Carbon-based composites were obtained from the respective bimetallic compound.•Luminescent properties were studies showing the europium and terbium transitions.•Metal-to-metal charge transfer between lanthanide ions was observed.