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 Bui 2 AlH (Bu = C4 H9 ) 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 Eu2+ , Tb3+ and Ru(bpy)3 2+ . CL enhancement was caused by energy transfer from the primary CL emitter (3 Me2 CHC(H)=O* aldehyde) to these ionic phosphors. The CL efficiency enhancement was in the order: Eu2+ (8.9 × 106 ) > Tb3+ (100) > Ru(bpy)3 2+ (50). The enhanced CL emitters were excited ions: Eu2+ *, λmax  = 465 nm; Tb3+ *, λmax  = 485, 542, 625 nm; and Ru(bpy)3 2+ *, λmax  = 567 nm. When two ions Eu2+ -Tb3+ or Eu2+ -Ru(bpy)3 2+ were present in the reaction solution, the efficiency of CL enhancement by Tb3+ or Ru(bpy)3 2+ 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)3 2+ *. Emission intensity of the Eu2+ * ion in these emitter doublets is much lower than when only one Eu2+ ion is present in solution.