Lima Patricia P, Sá Ferreira Rute A, Freire Ricardo O, Almeida Paz Filipe A, Fu Lianshe, Alves Severino, Carlos Luis D, Malta Oscar L
Departamento de Física, CICECO, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
Chemphyschem. 2006 Mar 13;7(3):735-46. doi: 10.1002/cphc.200500588.
New europium and gadolinium tris-beta-diketonate complexes have been prepared and incorporated in sol-gel-derived organic-inorganic hybrids, named di-ureasils. The general formula [Ln(btfa)3(4,4'-bpy)(EtOH)] (Ln=Eu, Gd; 4,4'-bpy=4,4'-bipyridine; btfa=4,4,4-trifluoro-1-phenyl-1,3-butanedione) for the complexes was confirmed by X-ray crystallography and elemental analysis. The ground-state geometry of the Eu3+ complex was calculated from the Sparkle/AM1 model. The calculated quantum yield obtained from the Sparkle model and from the crystal structure (both 46%) are in satisfactory agreement with the experimental value (38+/-4%). In the isolated complex the most efficient luminescence channel is S0-->S1-->T-->(5D1, 5D0)-->7F0-6, where the exchange mechanism dominates in the energy-transfer channel T-->(5D1, 5D0). For the Eu3+-based di-ureasils a 50% quantum yield enhancement compared to the Eu3+ complex is observed, which suggests an effective hybrid host-metal ion interaction and an active energy-transfer channel between the hybrid host and the Eu3+ complex. The Eu3+-based di-ureasils are photostable under UVA (360 nm) excitation, whereas under UVB (320 nm) and UVC (290 nm) photodegradation occurs.
新型铕和钆三-β-二酮配合物已被制备，并被纳入溶胶-凝胶衍生的有机-无机杂化材料中，称为双脲硅。通过X射线晶体学和元素分析确定了配合物的通式[Ln(btfa)3(4,4'-bpy)(EtOH)]（Ln = Eu、Gd；4,4'-bpy = 4,4'-联吡啶；btfa = 4,4,4-三氟-1-苯基-1,3-丁二酮）。从Sparkle/AM1模型计算出Eu3+配合物的基态几何结构。从Sparkle模型和晶体结构计算得到的量子产率（均为46%）与实验值（38±4%）吻合良好。在孤立的配合物中，最有效的发光通道是S0→S1→T→(5D1, 5D0)→7F0-6，其中在能量转移通道T→(5D1, 5D0)中交换机制占主导。对于基于Eu3+的双脲硅，观察到与Eu3+配合物相比量子产率提高了50%，这表明杂化主体与金属离子之间存在有效的相互作用以及杂化主体与Eu3+配合物之间存在活跃的能量转移通道。基于Eu3+的双脲硅在UVA（360 nm）激发下是光稳定的，而在UVB（320 nm）和UVC（290 nm）激发下会发生光降解。
