Tsurui Makoto, Kitagawa Yuichi, Fushimi Koji, Gon Masayuki, Tanaka Kazuo, Hasegawa Yasuchika
Graduate School of Chemical Sciences and Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo 060-8628, Japan.
Faculty of Engineering, Kita 13, Nishi 8, Kita-ku, Sapporo, 060-8628, Japan and Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Kita 21, Nishi 10, Kita-ku, Sapporo 001-0021, Japan.
Dalton Trans. 2020 Apr 28;49(16):5352-5361. doi: 10.1039/d0dt00699h.
Luminescent Eu(iii) complexes with point-chiral phosphine oxide ligands, [Eu(hfa)3((R,R)-B2QPO)] (hfa: hexafluoroacetylacetonato, B2QPO: 2,3-bis(tert-butylmethylphosphine oxide)quinoxaline) and [Eu(hfa)3((R)-B3QPO)] (B3QPO: 2-tert-butylmethylphosphine oxide-3-(di-tert-butylphosphineoxide)quinoxaline), are reported for the investigation of the electronic strain effect on the coordination sphere. Single crystal X-ray crystallography reveals the strong structural strain of the hfa ligands in [Eu(hfa)3((R,R)-B2QPO)]. The emission quantum yields of [Eu(hfa)3((R,R)-B2QPO)] in solution (55%) and solid (63%) are comparable to those of previously reported bright luminescent Eu(iii) complexes. The chiroptical properties of [Eu(hfa)3((R,R)-B2QPO)] and [Eu(hfa)3((R)-B3QPO)] were characterized using circular dichroism (CD) and circularly polarized luminescence (CPL) spectra. The dissymmetry factor of [Eu(hfa)3((R,R)-B2QPO)] was estimated to be 0.08. The chiroptical phenomena of the Eu(iii) complexes are closely related to their structural (geometry) and electronic (LMCT: ligand-to-metal charge transfer) strains.
报道了具有点手性氧化膦配体的发光铕（III）配合物，即[Eu(hfa)3((R,R)-B2QPO)]（hfa：六氟乙酰丙酮，B2QPO：2,3-双（叔丁基甲基氧化膦）喹喔啉）和[Eu(hfa)3((R)-B3QPO)]（B3QPO：2-叔丁基甲基氧化膦-3-（二叔丁基氧化膦）喹喔啉），用于研究配位球上的电子应变效应。单晶X射线晶体学揭示了[Eu(hfa)3((R,R)-B2QPO)]中hfa配体的强烈结构应变。[Eu(hfa)3((R,R)-B2QPO)]在溶液（55%）和固体（63%）中的发射量子产率与先前报道的明亮发光铕（III）配合物相当。使用圆二色性（CD）和圆偏振发光（CPL）光谱对[Eu(hfa)3((R,R)-B2QPO)]和[Eu(hfa)3((R)-B3QPO)]的手性光学性质进行了表征。[Eu(hfa)3((R,R)-B2QPO)]的不对称因子估计为0.08。铕（III）配合物的手性光学现象与其结构（几何形状）和电子（配体到金属电荷转移：LMCT）应变密切相关。
