S-Oxidized Dyes

荧光在可见光波长区以外的染料是生物成像的理想选择。 因为很少有内源发色团能够吸收波长超过 700 nm，光信号的衰减更小，光毒性更低， 自发荧光背景。为了实现这些更长时间的吸收和荧光 波长，相应地扩展的p系统通常是必需的。用这些较大的染料 随之而来的限制，如增加疏水表面积和非辐射弛豫 小路。近年来，实现荧光染料大红移的适用策略 通过借用竖井有机电子材料的想法，发生了戏剧性的变化。我- 罗丹明在它们的桥联位置结合了一个二甲基硅基，它使两个 吸收和荧光波长约为100 nm。因此，这些染料已经有了无数 从单分子和超分辨技术到体内的生物医学应用 成像方法。最近，其他第二排元素，如磷和硫 已经显示出更大的降低LUMO的效果。例如，可以在以下位置找到的一种砜桥 噻吩型二氧化硅光学材料S、S已被改用来构筑磺化罗丹明染料 吸收并发出超过700纳米的荧光。然而，与Si-的二甲基硅基桥基一样， 罗丹明，磺酸桥基没有官能化的连接点，也没有 进一步微调排放的手段。我们假设S-亚胺桥联染料会使染料变得容易 光稳定的近红外染料的光物理和溶解性的调制以及 允许容易地引入用于连接到生物分子和传感器的功能手柄 半个。

Dyes that fluoresce beyond the visible wavelength region are ideal for biological imaging. Because there are few endogenous chromophores capable of absorbing at wavelengths over 700 nm, there is less attenuation of the optical signal, lower phototoxicity, and less autofluorescence background. In order to achieve absorption and fluorescence at these longer wavelengths, correspondingly extended p-systems are typically required. With these larger dyes come limitations, such as increased hydrophobic surface area and non-radiative relaxation pathways. Recently, the applicable strategies to achieve large red-shifts in fluorescent dyes changed dramatically, with an idea borrowed from silole organic electronic materials. Si- rhodamines incorporate a dimethylsilyl group in their bridging position, which red-shifts both absorption and fluorescence by ~100 nm. Accordingly, these dyes have had numerous biomedical applications ranging from single-molecule and super-resolution techniques to in vivo imaging methods. More recently, other second-row elements such as phosphorus and sulfur have shown even larger LUMO-lowering effects. For example, a sulfone bridge, found in thiophene S,S-dioxide optical materials, has been adapted to construct sulfone-rhodamine dyes that absorb and fluoresce over 700 nm. However, like the dimethylsilyl bridging group of Si- rhodamines, the sulfone bridging group has no attachment point for functionalization and no means to further fine-tune emission. We hypothesize that S-imine-bridged dyes will allow facile modulation of the photophysical and solubility properties of photostable near-IR dyes, as well as allow the easy introduction of functional handles for attachment to biomolecules and sensor moieties.