Europium and Terbium Coordination Polymers Assembled from Hexacarboxylate Ligands: Structures and Luminescent Properties

详细信息    查看全文

• 作者：Yanli Gai ; Feilong Jiang ; Lian Chen ; Mingyan Wu ; Kongzhao Su ; Jie Pan ; Xiuyan Wan ; Maochun Hong
• 刊名：Crystal Growth & Design
• 出版年：2014
• 出版时间：March 5, 2014
• 年：2014
• 卷：14
• 期：3
• 页码：1010-1017
• 全文大小：555K
• 年卷期：v.14,no.3(March 5, 2014)
• ISSN：1528-7505

文摘

Six lanthanide coordination polymers of the formula [Ln(L¹)_0.5(H₂O)₂]路2H₂O [where Ln³⁺: Eu³⁺ (1), Tb³⁺ (2), and Gd³⁺(3)] and [Me₂NH₂][Ln(H₂L²)(H₂O)₄]路0.5DMF路xH₂O [where Ln³⁺: Eu³⁺ (4), Tb³⁺ (5), and Gd³⁺(6)], based on p-terphenyl-2,2鈥?2鈥?5,5鈥?5鈥?hexacarboxylate acid (H₆L¹), and p-terphenyl-3,2鈥?3鈥?5,5鈥?5鈥?-hexacarboxylate acid (H₆L²), have been solvothermally synthesized and structurally characterized. Complexes 1鈥?b>3 are 3D frameworks exhibiting 6-connected pcu alpha-Po primitive cubic network with topology (4¹².6³), while complexes 4鈥?b>6 show two-dimensional (2D) architectures showing simplified 3,4-connected binodal net and (4.6²)(4².6².8²) topology. Detailed photophysical behaviors have been explored on Eu³⁺, Tb³⁺, and Gd³⁺ complexes. The calculated triplet state energies of H₆L¹ and H₆L² lie above the emissive levels of Eu³⁺ or Tb³⁺ in an ideal range for sensitizing. Furthermore, it is demonstrated that the optimum energy gap between the triplet state of ligand H₆L¹ and the emissive level of Tb³⁺ ion makes the overall quantum yield of Tb³⁺ complex (2) larger than its corresponding Eu³⁺ complex (1). In addition, the coordinated water in the inner sphere has a significant negative influence on the overall quantum yield, especially for the Eu³⁺ complex (4) compared to the Tb³⁺ complex (5), due to the deactivation process caused by vibrational OH oscillators.