Luminescence Spectra Of Compounds Research Articles

Bimetallic 3d—4f-molecules [MEu(ButCOO)5(1,10-phen)] (M = Zn2+, Co2+, phen is phenanthroline): synthesis, structure, luminescent and magnetic properties

New heterometallic complexes [MEu(Piv)5(1,10-phen)]•MeCN (M = Zn2+ (1), Co2+ (2), Piv– = ButCOO–, 1,10-phen is 1,10-phenanthroline) were obtained. Luminescence spectra of compound 1 reveal a metal-centered Eu3+ luminescence, the luminescence lifetime is about 1 ms. Using TGA and DSC methods, it was shown that [ZnEu(Piv)5(1,10-phen)] is a stable binuclear molecule undergoing a structural transformation in the 210—230 °C temperature range, which leads to a partial transition of the sample into the glass state. Complex 2 does not exhibit luminescence due to the presence of high-spin cobalt(II) ions. The magnetic behavior of 2 according to calculations based on the molecular field model is determined by spin-orbit interactions of cobalt(II) and europium(III) ions.

Synthesis, structure, and properties of trinuclear pivalate {Zn2Eu} complexes with N-donor ligands

New luminescent heterometallic complexes of Eu3+ and Zn2+ were synthesized: Zn2Eu(NO3)(Piv)6(L)2 (Piv is pivalate anion, L = MeCN (1), 2,3-lutidine (2), 2,2′-bpy (3)) and [Zn2(Piv)3(2,2′-bpy)2][ZnEu(NO3)3(Piv)3(2,2′-bpy)] (4). In the case of 2,2′-bpy, the order of mixing of the reagents ([Zn(Piv)2] n , Eu(NO3)3·6H2O, and 2,2′-bpy) affects the composition of the final reaction product: the reaction of [Zn(Piv)2] n and Eu(NO3)3·6H2O (in the ratio Zn : Eu = 3 : 1) in MeCN affords complex 1 and the subsequent addition of 2,2′-bpy (Zn : L = 1 : 1) affords complex 3. Complex 4 is formed in the reaction of [Zn(Piv)2] n and 2,2′-bpy (Zn : L = 1 : 1) in MeCN followed by the addition of Eu(NO3)3·6H2O (Zn : Eu = 3 : 1). The luminescence spectra of compounds 1–4 (Zn : Eu = 3 : 1) exhibit metal-centered luminescence of Eu3+. The most efficient ligand-antenna is 2,2′-bpy, which is due to the optimum position of the triplet level of this ligand.