Synthesis and Characterization of Coordination Compound [Eu(µ2-OC2H5)(btfa)(NO3)(phen)]2phen with High Luminescence Efficiency

Abstract

A high-luminescent, blue-light excitable europium(III) coordination complex, [Eu(µ₂-OC₂H₅)(btfa)(NO₃)(phen)]₂phen (1) {btfa = benzoyl trifluoroacetone, phen = 1,10-phenantroline}, has been synthesized and investigated. The complex was characterized by infrared (IR) and photoluminescence (PL) spectroscopy. The PL emission spectra of powder samples registered in a range of 10.7–300 K exhibit characteristic metal-centered luminescence bands, assigned to internal radiative transitions of the Eu³⁺ ion, ⁵D₁→⁷F_j and ⁵D₀→⁷F_j (j = 0–4). The high-resolution spectrum of the transition ⁵D₀→⁷F₀ shows that it consists of two narrow components, separated by 0.96 meV, which indicates the presence in the matrix of two different sites of the Eu³⁺ ion. The splitting pattern of ⁵D₀→⁷F_j (j = 0–4) transitions indicates that europium ions are located in a low-symmetry environment. The absolute quantum yield and the sensitization efficiency were determined to be 49.2% and 89.3%, respectively. The complex can be excited with low-cost lasers at around 405 nm and is attractive for potential applications in optoelectronics and biochemistry.