Divalent Eu²⁺ ion – an effective inorganic mediator of energy transfer from the primary chemiluminescence emitter ³Me₂CHC(H)=O* on Tb³⁺ and Ru(bpy)₃²⁺ ions

Abstract

This study demonstrated for the first time that chemiluminescence (CL) from oxidation of Bui2AlH (Bu = C4H9) using oxygen from tetrahydrofuran (THF) was significantly enhanced by the addition of Ru(bpy)32+. A quantitative comparison of the enhancement efficiency of this CL was performed by addition of ionic phosphors Eu2+, Tb3+ and Ru(bpy)32+. CL enhancement was caused by energy transfer from the primary CL emitter (3Me2CHC(H)=O* aldehyde) to these ionic phosphors. The CL efficiency enhancement was in the order: Eu2+ (8.9 × 106) > Tb3+ (100) > Ru(bpy)32+ (50). The enhanced CL emitters were excited ions: Eu2+*, λmax = 465 nm; Tb3+*, λmax = 485, 542, 625 nm; and Ru(bpy)32+*, λmax = 567 nm. When two ions Eu2+–Tb3+ or Eu2+–Ru(bpy)32+ were present in the reaction solution, the efficiency of CL enhancement by Tb3+ or Ru(bpy)32+ ions was much higher, being 1.2 × 106 and 4.2 × 104, respectively. In this case, two excited ions were simultaneously registered as CL emitters: Eu2+* and Tb3+* or Eu2+* and Ru(bpy)32+*. Emission intensity of the Eu2+* ion in these emitter doublets is much lower than when only one Eu2+ ion is present in solution.