Microporous organosilicas assembled from polysilsesquioxane (POSS) building blocks are promising materials that are yet to be explored in-depth. Here, we investigate the processing and molecular structure of bispropylurea bridged POSS (POSS-urea), synthesised through the acidic condensation of 1,3-bis(3-(triethoxysilyl)propyl)urea (BTPU). Experimentally, we show that POSS-urea has excellent functionality for molecular recognition toward acetonitrile with an adsorption level of 74 mmol/g, which compares favourably to MOFs and zeolites, with applications in volatile organic compounds (VOC). The acetonitrile adsorption capacity was 132-fold higher relative to adsorption capacity for toluene, which shows the pores are highly selective towards acetonitrile adsorption due to their size and arrangement. Theoretically, our tight-binding density functional and molecular dynamics calculations demonstrated that this BTPU based POSS is microporous with an irregular placement of the pores. Structural studies confirm maximal pore sizes of ∼1 nm, with POSS cages possessing an approximate edge length of ∼3.16 Å.

由聚倍半硅氧烷（POSS）构件组装而成的微孔有机硅是有前途的材料，有待进一步深入研究。在这里，我们研究了通过1,3-双（3-（三乙氧基甲硅烷基）丙基）脲（BTPU）的酸性缩合合成的双丙基脲桥联POSS（POSS-脲）的加工和分子结构。实验表明，POSS-脲具有出色的官能度，可对乙腈进行分子识别，其吸附水平为74 mmol / g，与MOF和沸石相比具有优势，可用于挥发性有机化合物（VOC）。乙腈的吸附能力比甲苯的吸附能力高132倍，这表明孔的大小和排列对乙腈吸附具有很高的选择性。从理论上讲 我们的紧密结合密度泛函和分子动力学计算表明，这种基于BTPU的POSS是微孔的，孔的排列不规则。结构研究证实最大孔径为〜1 nm，POSS笼的边缘长度约为〜3.16Å。