Estimating the Individual Spectroscopic Properties of Three Unique Eu-III Sites in a Coordination Polymer

Author(s)

Monteiro, Jorge H. S. K. ^{[1, 2]} ; Dutra, Jose D. L. ^[3] ; Freire, Riicardo O. ^[3] ; Formiga, Andre L. B. ^[1] ; Mazali, Italo O. ^[1] ; de Bettencourt-Dias, Ana ^[2] ; Sigoli, Fernando A. ^[1]

Affiliation

^[1] Univ Estadual Campinas, Inst Chem, BR-13083970 Sao Paulo - Brazil

^[2] Univ Nevada, Dept Chem, Reno, NV 89557 - USA

^[3] Univ Fed Sergipe, Dept Chem, BR-49100000 Sao Cristovao, Sergipe - Brazil

• Document type: Journal article
• Source: Inorganic Chemistry; v. 57, n. 24, p. 15421-15429, DEC 17 2018.
• Web of Science Citations: 2

Abstract

We isolated a coordination polymer with the formula {[}Eu-3(3,5-dcba)(9)(H2O)(dmf)(3)]center dot 2dmf, with three unique Eu-III coordination sites in the asymmetric unit, with the Eu-III ions bridged by 3,5-dichlorobenzoato (3,5-dcba) ligands. The coordination polymer crystallized in the triclinic space group P (1) over bar with unit cell dimensions a = 12.4899(15), b = 16.326(2), and c = 25.059(3) angstrom, a = 84.271(3)degrees, beta = 84.832(3), and gamma = 68.585(3)degrees and V = 4725.2(10) angstrom(3). The characteristic D-5(0) -> F-7(J) = 0-4) Eu-III transitions were observed upon ligand-centered excitation. Emission lifetimes of 0.825 +/- 0.085 and 1.586 +/- 0.057 ms were observed and were attributed to the sites with coordination of water or dimethylformamide (dmf) molecules to each ion, respectively. Through a combination of spectroscopy and calculations, we determined the photophysical properties of each unique Eu-III site. Energy-transfer rates ligand -> Eu-III were determined for each unique site using the overlapped polyhedra method. The rates depend on the coordinated water molecules and the different donor acceptor distances. The two sites without coordinated water molecules and shortest donor acceptor-distance display the fastest energy-transfer rate ligand -> Eu-III, whereas the site with coordinated water molecules and longest donor-acceptor distance displays the slowest energy-transfer rate. Donor acceptor distances were estimated computationally and were confirmed by calculating the frontier orbitals in the asymmetric units of the polymer using density functional theory. (AU)

• FAPESP's process: 09/54066-7 - Multi-User Laboratory for Advanced Optical Spectroscopy
• Grantee: Yoshitaka Gushikem
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 13/22127-2 - Development of novel materials strategic for integrated analytical devices
• Grantee: Lauro Tatsuo Kubota
• Support Opportunities: Research Projects - Thematic Grants