Dröge Fabian, Noakes Felicity F, Archer Stuart A, Sreedharan Sreejesh, Raza Ahtasham, Robertson Craig C, MacNeil Sheila, Haycock John W, Carson Heather, Meijer Anthony J H M, Smythe Carl G W, Bernardino de la Serna Jorge, Dietzek-Ivanšić Benjamin, Thomas Jim A
Institute of Physical Chemistry, Helmholtzweg 4, 07743 Jena, Germany; Institute of Photonic Technology Jena e.V., Albert-Einstein-Straße 9, 07749 Jena, Germany.
Central Laser Facility, Rutherford Appleton Laboratory, Research Complex at Harwell, Science and Technology Facilities Council, Harwell-Oxford, Didcot OX11 0QX, United Kingdom; National Heart and Lung Institute, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, London SW7 2AZ, United Kingdom.
J Am Chem Soc. 2021 Dec 8;143(48):20442-20453. doi: 10.1021/jacs.1c10325. Epub 2021 Nov 22.
With the aim of developing photostable near-infrared cell imaging probes, a convenient route to the synthesis of heteroleptic Os complexes containing the Os(TAP) fragment is reported. This method was used to synthesize the dinuclear Os complex, [{Os(TAP)}tpphz] (where tpphz = tetrapyrido[3,2-a:2',3'-c:3″,2''-h:2‴,3'''-j]phenazine and TAP = 1,4,5,8- tetraazaphenanthrene). Using a combination of resonance Raman and time-resolved absorption spectroscopy, as well as computational studies, the excited state dynamics of the new complex were dissected. These studies revealed that, although the complex has several close lying excited states, its near-infrared, NIR, emission (λ = 780 nm) is due to a low-lying Os → TAP based MCLT state. Cell-based studies revealed that unlike its Ru analogue, the new complex is neither cytotoxic nor photocytotoxic. However, as it is highly photostable as well as live-cell permeant and displays NIR luminescence within the biological optical window, its properties make it an ideal probe for optical microscopy, demonstrated by its use as a super-resolution NIR STED probe for nuclear DNA.
为了开发光稳定的近红外细胞成像探针，本文报道了一种合成含Os(TAP)片段的杂配Os配合物的简便方法。该方法用于合成双核Os配合物[{Os(TAP)}tpphz]（其中tpphz = 四吡啶并[3,2-a:2',3'-c:3″,2''-h:2‴,3'''-j]菲嗪，TAP = 1,4,5,8-四氮杂菲）。结合共振拉曼光谱和时间分辨吸收光谱以及计算研究，剖析了新配合物的激发态动力学。这些研究表明，尽管该配合物有几个相近的激发态，但其近红外（NIR）发射（λ = 780 nm）源于一个基于Os→TAP的低位金属-配体电荷转移（MCLT）态。基于细胞的研究表明，与它的Ru类似物不同，新配合物既无细胞毒性也无光细胞毒性。然而，由于它具有高度的光稳定性、可穿透活细胞并在生物光学窗口内显示近红外发光，其特性使其成为光学显微镜的理想探针，作为核DNA的超分辨率近红外受激发射损耗（STED）探针的应用证明了这一点。
