S-Oxidized Dyes

在可见光波长范围之外发荧光的染料是生物成像的理想选择。 因为很少有内源性发色团能够吸收波长超过 在700 nm处，光信号衰减较小，光毒性较低， 自体荧光背景。为了在这些较长的波长下实现吸收和荧光， 因此，在波长上，通常需要相应扩展的p系统。用这些较大的染料 存在限制，例如增加的疏水表面积和非辐射弛豫 途径。近年来，实现荧光染料大红移的可行策略 从silole有机电子材料中借鉴的想法，是的 若丹明在它们的桥位上结合了二甲基甲硅烷基， 通过~100 nm的吸收和荧光。因此，这些染料具有许多优点。 生物医学应用，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，砜桥，发现于 噻吩S，S-二氧化物光学材料，已被用于构建砜-罗丹明染料 在700纳米以上吸收并发出荧光。然而，与Si-的二甲基甲硅烷基桥连基一样， 若丹明，砜桥连基团没有用于官能化的连接点， 进一步微调排放的手段。我们假设S-亚胺桥连的染料将允许容易的 调制光稳定近红外染料的物理和溶解度性质，以及 允许容易地引入用于附着到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.