Divalent Eu 2+ ion – an effective inorganic mediator of energy transfer from the primary chemiluminescence emitter 3 Me 2 CHC(H)=O* on Tb 3+ and Ru(bpy) 3 2+ ions

This study demonstrated for the first time that chemiluminescence (CL) from oxidation of Bu i 2 AlH (Bu = C 4 H 9 ) using oxygen from tetrahydrofuran (THF) was significantly enhanced by the addition of Ru(bpy) 3 2+ . A quantitative comparison of the enhancement efficiency of this CL was performed by addition of ionic phosphors Eu 2+ , Tb 3+ and Ru(bpy) 3 2+ . CL enhancement was caused by energy transfer from the primary CL emitter ( 3 Me 2 CHC(H)=O* aldehyde) to these ionic phosphors. The CL efficiency enhancement was in the order: Eu 2+ (8.9 × 10 6 ) > Tb 3+ (100) > Ru(bpy) 3 2+ (50). The enhanced CL emitters were excited ions: Eu 2+ *, λ max  = 465 nm; Tb 3+ *, λ max  = 485, 542, 625 nm; and Ru(bpy) 3 2+ *, λ max  = 567 nm. When two ions Eu 2+ –Tb 3+ or Eu 2+ –Ru(bpy) 3 2+ were present in the reaction solution, the efficiency of CL enhancement by Tb 3+ or Ru(bpy) 3 2+ ions was much higher, being 1.2 × 10 6 and 4.2 × 10 4 , respectively. In this case, two excited ions were simultaneously registered as CL emitters: Eu 2+ * and Tb 3+ * or Eu 2+ * and Ru(bpy) 3 2+ *. Emission intensity of the Eu 2+ * ion in these emitter doublets is much lower than when only one Eu 2+ ion is present in solution.