A relation between the structural diversity and photoluminescent properties in three new classes of Eu3+ hydrocinnamate complexes containing N,N-bidentate and N,N,N-tridentate ancillary ligands

Abstract

In this work, we present the synthesis, solid state characterization and complete photoluminescence study of three new photoluminescent Eu3+ hydrocinnamate complexes containing the N,N- bidentate and N,N,N-tridentate ancillary ligands 2, 2’: 6′,2″-terpyridine (terpy), 4,4′-dimethyl-2,2′- bipyridine (4,4′-dmbpy) and bathophenanthroline (bath). The spectroscopic and analytical techniques indicate the formation of compounds with the formulas [Eu (cin)3(H2O) (terpy)]. H2O (1), [Eu2 (cin)6 (4,4′-dmbpy)2] (2) and [Eu2 (cin)6 (bath)2] (3), with the monometallic and homobimetallic nature related to the type of ancillary ligand, as evidenced by powder X-ray diffaction data. Through the RM1 model, the optimized ground state geometries of the complexes were obtained, and posteriorly used in the energy transfer elucidation process. The photoluminescent properties show an intimate relationship with the molecular structures, where the 5D0 → 7F0 transition energy and Ω2 Judd-Ofelt parameter value are reflected in the coordination numbers and modes of the carboxylate groups. The intense red emission and structure/photoluminescence interrelationship can opens the possibility to development of new spectroscopic probes based on the Eu3+ coordination compounds.