Department of Chemistry, James Madison University, Harrisonburg, Virginia 22807, USA.
Inorg Chem. 2012 Mar 19;51(6):3355-65. doi: 10.1021/ic201114u. Epub 2012 Mar 6.
A suite of Ru(II) complexes in which one ligand is pH responsive and the other two are varied in an effort to achieve improved photophysics has been synthesized and their potential as pH reporters assessed. The more general purpose of the study was to examine the role of the accessory ligands in heteroleptic reporter complexes and the degree to which such ligands can affect the performance of luminescent reporters. For this suite of complexes, judicious choice of the accessory ligand can alter both the pK(a)* and the dynamic range of response. It was found that the emission color and brightness were influenced by pH, but the lifetimes were only weakly affected. Surprisingly, some accessory ligands which should have improved luminescent properties essentially turned off the pH response. Several possible reasons for this observation are explored. It is suggested, and density functional theory (DFT) calculations support, that the relative π* levels of the pH sensitive and the accessory ligands are critical.
已合成了一系列 Ru(II) 配合物，其中一个配体对 pH 具有响应性，另外两个配体则有所变化，以努力提高光物理性能，并评估其作为 pH 报告物的潜力。该研究的更普遍目的是研究辅助配体在异核报告物配合物中的作用，以及此类配体在多大程度上可以影响发光报告物的性能。对于这一系列配合物，明智地选择辅助配体可以改变 pK(a)和响应动态范围。结果发现，发射颜色和亮度受 pH 影响，但寿命仅受弱影响。令人惊讶的是，一些本应改善发光性能的辅助配体实际上关闭了 pH 响应。探讨了这种观察结果的几种可能原因。有人提出，并且密度泛函理论（DFT）计算支持，pH 敏感配体和辅助配体的相对 π能级是关键。
