A linear donor-π-acceptor-π-donor (D-π-A-π-D) type 4-methoxyphenyl 1 and 4-ferrocenylphenyl 2 conjugated borasiloxanes were synthesized and characterized by various spectroscopic techniques (FT-IR, NMR and HRMS). Further, the molecular structure of 4-methoxyphenyl borasiloxane 1 was confirmed by the single-crystal X-ray diffraction method, shows a monoclinic crystal system in the centrosymmetric space group (P2₁/c) with various non-covalent interactions in the crystal packing. The intramolecular charge transfer (ICT) process of both the borasiloxanes were studied using the solvatochromic technique, which shows negative solvatochromism for 1 and 2, due to the high ground state dipole moment than the excited states. The second-order nonlinear optical (NLO) properties of the borasiloxanes were studied using Kurtz and Perry powder method. Compound 1 was crystallized in a centrosymmetric crystal system, and it exhibits second-order NLO response, because of the distorted silicon environment in an eight-membered borasiloxane ring with various C–H...π interactions in the crystal packing. The 4-ferrocenylphenyl borasiloxane 2 shows 1.5 times higher SHG efficiency than 1, due to the ferrocene moiety is conjugated in the para position of the borasiloxane ring, which involves an effective one-electron transfer process (Fe^II ↔ Fe^III). Furthermore, the experimental results of optical and nonlinear optical properties of the borasiloxanes 1 and 2 were supported by the DFT and TD-DFT calculations using the B3LYP/6-31+G** level of theory.

合成了线性供体-π-受体-π-供体 (D-π-A-π-D) 型 4-甲氧基苯基1和 4-二茂铁基苯基2共轭硼硅氧烷，并通过各种光谱技术（FT-IR、NMR 和 HRMS）进行表征）。此外，4-甲氧基苯基硼硅氧烷1的分子结构由单晶 X 射线衍射法证实，在中心对称空间群 (P2 ₁ /c) 中显示单斜晶系，在晶体堆积中具有各种非共价相互作用. 使用溶剂化显色技术研究了两种硼硅氧烷的分子内电荷转移 (ICT) 过程，该技术显示1和2 的负溶剂化显色，由于基态偶极矩比激发态高。使用 Kurtz 和 Perry 粉末方法研究了硼硅氧烷的二阶非线性光学 (NLO) 特性。化合物1在中心对称晶体系统中结晶，并且它表现出二阶 NLO 响应，因为八元硼硅氧烷环中的硅环境扭曲，在晶体堆积中具有各种 C-H...π 相互作用。4-二茂铁基苯基硼硅氧烷2显示出比1高 1.5 倍的 SHG 效率，因为二茂铁部分共轭在硼硅氧烷环的对位，这涉及有效的单电子转移过程（Fe ^II ↔ Fe ^III）。此外，硼硅氧烷1和2的光学和非线性光学性质的实验结果得到了使用 B3LYP/6-31+G** 理论水平的 DFT 和 TD-DFT 计算的支持。