S-Oxidized Dyes

发出超出可见波长范围荧光的染料是生物成像的理想选择。 因为很少有内源生色团能够吸收超过 700 nm，光信号衰减较小，光毒性较低， 自发荧光背景。为了在这些更长的时间内实现吸收和荧光 波长，通常需要相应扩展的 p 系统。使用这些较大的染料 存在局限性，例如增加疏水表面积和非辐射弛豫 途径。最近，实现荧光染料大红移的适用策略 借用了噻咯有机电子材料的想法，它发生了巨大的变化。硅- 罗丹明在其桥接位置上结合了二甲基甲硅烷基，这使得两者都发生红移 ~100 nm 的吸收和荧光。因此，这些染料具有多种 生物医学应用范围从单分子和超分辨率技术到体内 成像方法。最近，其他第二行元素，如磷和硫 显示出更大的 LUMO 降低效应。例如，磺桥，存在于 噻吩S,S-二氧化物光学材料，已被用于构建砜-罗丹明染料 吸收并发出超过 700 nm 的荧光。然而，像 Si- 的二甲基甲硅烷基桥基一样 罗丹明，砜桥基没有功能化的连接点，也没有 意味着进一步微调排放。我们假设 S-亚胺桥联染料将允许轻松 光稳定近红外染料的光物理和溶解度特性的调节，以及 允许轻松引入用于连接生物分子和传感器的功能手柄 部分。

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.