Abstract

Trivalent lanthanide ions show interesting optical properties. Keeping this in view, five Sm(III) complexes were synthesized using 4-oxo-4H-1-benzopyran-3-carboxaldehyde (L) as primary ligand along with 1,10-Phenanthroline (Phen); Bipyridine (Bipy); Bathophenanthroline (Bathophen) and Neocuproine (Neo) as secondary ligands. Characterizations of prepared complexes were carried out by means of FTIR, elemental analysis, UV–vis, ESI-MS⁺, thermal studies, PXRD, FESEM, and luminescence studies. Thermal studies confirmed the good thermal stability of complexes. Sharp peaks in X-ray diffractograms suggest their crystalline nature. The photoluminescence process in complexes has been thoroughly studied and discussed in liquid and powder state. The complexes show ⁴G_5/2→⁶H_j transitions where j = 5/2, 7/2, and 9/2, analogous to characteristic emission peaks of Sm(III) ion at ~ 566, 601, and 648 nm, respectively. The complexes demonstrate intense emission peaks at ~ 601 in liquid and ~ 648 nm in a powder state, which is responsible for bright orange and red emission, respectively. The synergistic effect of secondary ligands was responsible for longer luminescence lifetime and enhanced emission intensity in ternary complexes. Attractive photoluminescence properties of complexes could play a vital role in electroluminescent devices, bio-assays, liquid lasers, OLEDs, etc.

Graphic abstract

Five new Sm(III) complexes were synthesized using 4-oxo-4H-1-benzopyran-3-carboxaldehyde (L) and other N,N′-donor π-conjugated ligands. Results were in favour of the formation of bright orange (in solution) and red (in powder state) luminescent complexes exhibiting sharp Sm(III)-centered emission peaks. Hence, the selected ligands act as efficient sensitizers in transferring their excitation energy towards Sm(III) ion.

中文翻译：

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某些Sm（III）与4-oxo-4 H -1-苯并吡喃-3-甲醛和其他N，N'-给体π-共轭配体的配合物的光物理行为研究

摘要

三价镧系离子显示出令人感兴趣的光学性质。考虑到这一点，使用4-氧代-4 H -1-苯并吡喃-3-甲醛（L）作为主要配体与1,10-菲咯啉（苯）合成了五个Sm（III）配合物。联吡啶（Bipy）; 邻菲咯啉（Bathophen）和Neocuproine（Neo）作为二级配体。通过FTIR，元素分析，UV-vis，ESI-MS ⁺，热学，PXRD，FESEM和发光研究对所制备的复合物进行表征。热学研究证实了配合物具有良好的热稳定性。X射线衍射图中的尖峰表明其晶体性质。在液体和粉末状态下，已经对复合物中的光致发光过程进行了深入的研究和讨论。配合物显示⁴ G_5/2 → ⁶ H _j跃迁，其中j  = 5 / 2、7 / 2和9/2，分别类似于Sm（III）离子在〜566、601和648 nm处的特征发射峰。配合物在液体状态下在〜601处呈粉状状态，在〜648 nm处显示出强烈的发射峰，分别负责亮橙色和红色发射。二级配体的协同作用导致更长的发光寿命和增强的三元配合物的发射强度。配合物的引人注目的光致发光特性可以在电致发光器件，生物测定，液体激光器，OLED等中发挥至关重要的作用。

图形摘要

使用4-oxo-4 H -1-苯并吡喃-3-甲醛（L）和其他N，N'-供体π-共轭配体合成了五种新的Sm（III）配合物。结果有利于形成亮橙色（溶液中）和红色（粉末状态）发光络合物，并显示出以Sm（III）为中心的尖峰。因此，所选配体在将其激发能转移至Sm（III）离子时充当有效的敏化剂。