Solvent dependence of the emission intensities in photoluminescent mononuclear europium(III) complexes with tetradentate Schiff base ligands
Solvent dependence of the emission intensities in photoluminescent mononuclear europium(III) complexes with tetradentate Schiff base ligands
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DOI：
10.1016/j.poly.2018.04.010
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发表时间：
2018-07
期刊：
影响因子：
2.6
通讯作者：
M. Tsuchimoto;Masako Ookusa;Shuhei Itoh;Masayuki Watanabe;K. Nakajima
中科院分区：
文献类型：
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作者：
M. Tsuchimoto;Masako Ookusa;Shuhei Itoh;Masayuki Watanabe;K. Nakajima
具有不同抗衡阳离子的单核四齿希夫碱-铕(III)络合物，X[Eu(3,5-Clsalen)2] {X=(C2H5)3NH+, (C2H5)4N+, K+;制备了H2(3,5-Clsalen):N,N'-双-3,5-二氯水杨乙二胺}，并研究了铕(III)配合物在有机溶剂（CH3CN、DMSO、DMF、(CH3)2CO、CH3OH、N-甲基甲酰胺(NMF)、CH2Cl2）中的光致发光性质。所有配合物的发射光谱都显示出相似的发射光谱模式，基于溶剂中 365 nm 激发下的 f-f 跃迁。相反，配合物的发射强度在不同溶剂中变化很大。所有配合物 X[Eu(3,5-Clsalen)2] {X=(C2H5)3NH+, (C2H5)4N+, K+} 在极性质子溶剂中表现出强发射强度（在 CH3CN、DMF、DMSO 和 (CH3)2CO 中 Φ=0.24–0.42），在极性质子溶剂中表现出弱发射强度（Φ=0.052–0.10） (C2H5)3NH[Eu(3,5-Clsalen)2] 和 (C2H5)4N[Eu(3,5-Clsalen)2] 在 CH2Cl2 中 298K 时的发射强度显着不同 ((C2H5)3NH[Eu(3,5-Clsalen)2] 的发射强度显着不同 ((C2H5)3NH[Eu(3,5-Clsalen)2] 的发射强度显着不同 ((C2H5)3NH[Eu(3,5-Clsalen)2]对于 (C2H5)4N[Eu(3,5-Clsalen)2])，Φ=0.19。制备了单核钇(III)和钆(III)配合物X[Y(3,5-Clsalen)2]和X[Gd(3,5-Clsalen)2]{X=(C2H5)3NH+,(C2H5)4N+}。对(C2H5)3NH[Gd(3,5-Clsalen)2]进行X射线晶体结构分析。对钇(III)络合物的 1 H 和 13 C NMR 谱进行测量以阐明溶剂中络合物的结构。在 77K 下测量乙醇/甲醇 (1:1) 玻璃中钆 (III) 络合物的发光光谱，以估计三重态的能级。溶剂对络合物发射强度的影响可以通过溶剂分子或烷基铵阳离子在单核铕(III)络合物阴离子周围的O单键H、N单键H、C单键H振动引起的振动非辐射失活来解释。
Mononuclear tetradentate Schiff base–europium(III) complexes with different counter cations, X[Eu(3,5-Clsalen)2] {X = (C2H5)3NH+, (C2H5)4N+, K+; H2(3,5-Clsalen):N,N′-bis-3,5-dichlorosalicylideneethanediamine}, were prepared and photoluminescence properties of the europium(III) complexes in organic solvents (CH3CN, DMSO, DMF, (CH3)2CO, CH3OH,N-methylformamide (NMF), CH2Cl2) were investigated. All the emission spectra of the complexes displayed similar emission spectral patterns based on the f–f transitions by excitation with 365 nm in the solvents. In contrast, the emission intensities of the complexes varied greatly in the different solvents. All the complexes X[Eu(3,5-Clsalen)2] {X = (C2H5)3NH+, (C2H5)4N+, K+} displayed strong emission intensities in polar aprotic solvents (ϕ= 0.24–0.42 in CH3CN, DMF, DMSO, and (CH3)2CO), and weak emission intensities in polar protic solvents (ϕ= 0.052–0.10 in CH3OH and NMF) at 298 K. The emission intensities of (C2H5)3NH[Eu(3,5-Clsalen)2] and (C2H5)4N[Eu(3,5-Clsalen)2] in CH2Cl2at 298 K are significantly different (ϕ= 0.016 for (C2H5)3NH[Eu(3,5-Clsalen)2] andϕ= 0.19 for (C2H5)4N[Eu(3,5-Clsalen)2]). Mononuclear yttrium(III) and gadolinium(III) complexes X[Y(3,5-Clsalen)2] and X[Gd(3,5-Clsalen)2] {X = (C2H5)3NH+, (C2H5)4N+} were prepared. X-ray crystal structure analysis of (C2H5)3NH[Gd(3,5-Clsalen)2] was performed. Measurements of the1H and13C NMR spectra of the yttrium(III) complexes were performed to elucidate the structure of the complexes in the solvents. Measurement of the luminescence spectrum of the gadolinium(III) complex in ethanol/methanol (1:1) glass at 77 K was performed to estimate the energy level of the triplet state. The solvent effect on the emission intensities of the complexes is explained by the vibrational nonradiative deactivation caused by the Osingle bondH, Nsingle bondH, Csingle bondH vibrations of the solvent molecules, or alkylammonium cations, around the mononuclear europium(III) complex anion.