AbstractSulfate crystals typically exhibit minimal optical anisotropy due to the near‐zero polarizability anisotropy (δ) of [SO4]2− tetrahedra, arising from highly symmetrical electron clouds. Recent research sought to enhance δ via chemical modifications, such as fluorination. However, the resultant crystals often maintain subpar optical anisotropy, frequently with birefringence values below 0.1. In this study, we have uncovered that δ can be significantly strengthened by chemically tailoring the tetrahedral [SO4]2− with anisotropic π‐conjugated modules. This has been demonstrated by several newly proposed S−O‐Org (Org: π‐conjugated organic species) moieties, which show a sharp increase in δ based on theoretical computations. To further validate this experimentally, we synthesized and characterized six new 3‐pyridinesulfonate crystals with the formula A(3‐C5H4NSO3) ⋅ xH2O (A=Li, Ag, K, Rb, Cs, and NH4; x=0 and 1). Notably, these materials exhibit strong optical anisotropy, with birefringence values ranging from 0.240 to 0.312 at 546 nm. These values are approximately 23 to 145.5 times greater than those of corresponding sulfates, and they outperform a vast number of sulfate‐related optical materials, thus verifying the effectiveness of the proposed strategy. Furthermore, the title compounds exhibit diverse microstructure peculiarities influenced by the size and binding natures of the counter cations.
摘要
硫酸盐晶体通常表现出最小的光学各向异性,这是因为[SO4]2- 四面体的极化率各向异性(δ)接近零,这是由高度对称的电子云产生的。最近的研究试图通过
氟化等
化学修饰来增强δ。然而,由此产生的晶体往往保持着不理想的光学各向异性,双折射值经常低于 0.1。在这项研究中,我们发现通过
化学方法将四面体[SO4]2-与各向异性的π共轭模块进行定制,可以显著增强δ。一些新提出的 S-O-Org(Org:π-共轭有机物)分子就证明了这一点,根据理论计算,这些分子的δ会急剧增加。为了进一步从实验上验证这一点,我们合成并表征了六种新的
3-吡啶磺酸盐晶体,其分子式为 A(3-C5H4NSO3) ⋅ xH2O(A=Li、Ag、K、Rb、Cs 和 NH4;x=0 和 1)。值得注意的是,这些材料表现出很强的光学各向异性,在 546 纳米波长处的双折射值从 0.240 到 0.312 不等。这些数值约为相应
硫酸盐的 23 至 145.5 倍,优于大量与
硫酸盐相关的光学材料,从而验证了所提策略的有效性。此外,受反阳离子的大小和结合性质的影响,标题化合物表现出多种微观结构特征。