Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
Inorg Chem. 2010 Apr 5;49(7):3252-60. doi: 10.1021/ic9021239.
A series of phosphorescent zwitterionic iridium(III) complexes, with 4-carboxy-2, 2'-bipyridine-4'-carboxylate (Hdcbpy) as ancillary ligand, Ir(C(wedge)N)(2)(Hdcbpy) (C(wedge)N = 1-phenylpyrazole (ppz), 1-phenyl-pyridine (ppy), 2-(4',6'-difluoro-phenyl)pyridine (dfppy), 1-phenyl-isoquinoline (piq), dibenzo[f,h]quinoxaline (dbq)), were prepared and characterized. Their photophysical properties were studied, and intense luminescence emissions were observed based on metal-to-ligand-charge-transfer ((3)MLCT), ligand-to-ligand charge-transfer ((3)LLCT), ligand-centered transitions ((3)LC, i.e., (3)pi --> pi*), or intraligand-charge-transfer ((3)ILCT) excited states, which were confirmed by theoretical calculations. The quantum yield of Ir(dfppy)(2)(Hdcbpy) is as high as 0.106 in aqueous solution. With Hdcbpy as a hydrophilic part, their amphiphilic structures as further confirmed by X-ray single crystal data endow them with different solubilities in phosphate buffer solution (PBS, pH 7.0). The compounds were successfully applied as luminescent dyes for cell imaging in aqueous solution. Their different stain ability in cell imaging was fairly well supported by the experimental data based on the measurement of oil/water partition coefficients and encapsulation/release with liposomes.
一系列具有荧光性的两性离子铱(III)配合物，以 4-羧酸-2,2'-联吡啶-4'-羧酸（Hdcbpy）为辅助配体，Ir(C(wedge)N)(2)(Hdcbpy)（C(wedge)N = 1-苯基吡唑（ppz）、1-苯基吡啶（ppy）、2-(4',6'-二氟苯基)吡啶（dfppy）、1-苯基异喹啉（piq）、二苯并[f,h]喹喔啉（dbq）），被制备并进行了表征。研究了它们的光物理性质，观察到基于金属-配体电荷转移（(3)MLCT）、配体-配体电荷转移（(3)LLCT）、配体中心跃迁（(3)LC，即(3)pi --> pi*）或内配体电荷转移（(3)ILCT）激发态的强烈发光发射，这通过理论计算得到了证实。Ir(dfppy)(2)(Hdcbpy)在水溶液中的量子产率高达 0.106。Hdcbpy 作为亲水性部分，其两亲性结构进一步通过 X 射线单晶数据得到证实，赋予它们在磷酸盐缓冲溶液（PBS，pH 7.0）中不同的溶解度。这些化合物成功地作为荧光染料应用于水溶液中的细胞成像。基于油水分配系数的测量和脂质体的封装/释放，它们在细胞成像中的不同染色能力的实验数据得到了很好的支持。
