Preparation of calcium phosphate nanoparticles hybridized with europium(III) complex for novel luminescent organic-inorganic systems
Preparation of calcium phosphate nanoparticles hybridized with europium(III) complex for novel luminescent organic-inorganic systems
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DOI：
10.1016/j.jpcs.2018.06.031
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发表时间：
2018-11
影响因子：
4
通讯作者：
T. Kataoka;K. Shinozaki;S. Abe;M. Tagaya
中科院分区：
文献类型：
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作者：
T. Kataoka;K. Shinozaki;S. Abe;M. Tagaya
我们利用磷酸钙（CP）与三（2，2，6，6-四甲基-3，5-庚二酮）铕（EuTH）配合物之间的相互作用，合成了一种新型的无机-有机杂化体系，以阐明EuTH分子的状态。我们实现了成核和晶体生长的电子本地化的EuTH分子使用两种不同的合成过程（基于添加EuTH的CP成核阶段之前和之后的时间）。Eu 3+离子在杂化物上/内的配位环境发生了明显的变化，杂化物中Eu 3+离子具有较高的空间对称性。混合微晶的纵横比为2.5-6.0，表明EuTH分子选择性地与CP核的a面相互作用，以诱导晶体沿未覆盖的c面沿着择优生长。在磷酸盐缓冲液中，CP表面分离的EuTH分子抑制了混合物中Ca 2+的溶解。在激发光谱中，EuTH与磷酸根离子的相互作用导致了7 F0 → 5L 6跃迁，说明磷酸根离子影响了配合物的配位环境。在荧光光谱中，磁偶极跃迁（5D 0 → 7 F1）与电偶极跃迁（5D 0 → 7 F2）的发光强度之比高于EuTH和其它Eu 3+掺杂无机体系。因此，Eu ~（3+）离子的空间对称性越高，其发光强度和量子效率越高，这与磷的抗猝灭效应有关。在未来，CP杂化物与各种有机配合物将被制备，这些可以应用于生物医学领域，如在生物成像和药物输送系统。
We have synthesized novel inorganic–organic hybrid systems based on the interactions between calcium phosphate (CP) and tris(2,2,6,6-tetramethyl-3,5-heptanedionato)europium (III) (EuTH) complex to clarify the states of the EuTH molecules. We achieved the nucleation and crystal growth of electronically localized of EuTH molecules using two different synthetic processes (based on the timing of the addition EuTH before and after the CP nucleation stage). The coordination environment of the Eu3+ion inside/on the hybrids was clearly changed, having the higher spatial symmetry states in the hybrid. The aspect ratios of the hybrid crystallites were 2.5–6.0, suggesting that the EuTH molecules selectively interacted with thea–plane of the CP nuclei to induce preferential crystal growth along with the uncoveredc–plane. The segregated EuTH molecules on CP surfaces suppressed Ca2+dissolution from the hybrids in phosphate buffer saline. In the excitation spectra of the hybrids, the7F0→5L6transition appeared as a result of the interaction between the EuTH and phosphate ions, suggesting that the phosphate ions affected the coordination environment. In the luminescence spectra of the hybrids, the luminescence intensity ratio of the magnetic dipole transition (5D0→7F1) to electric dipole transition (5D0→7F2) were higher than those of EuTH and the other Eu3+-doped inorganic systems. Thus, the higher spatial symmetry states of the Eu3+ion in the hybrids resulted in greater luminescence intensities and quantum efficiencies, which would be affected by the phosphorus anti-quenching. In the future, CP hybrids with various organic complexes will be prepared, and these could be applied in the biomedical fields such as in bio-imaging and drug delivery systems.