论文标题
使用动态核极化NMR，弥漫性反射率红外傅立叶变换光谱和X射线光电学光谱法，使用动态核极化NMR探测苯乙烯桥周期性有机硅酸盐的探测功能和酸度
Probing Functionalities and Acidity of Calcined Phenylene-Bridged Periodic Mesoporous Organosilicates Using Dynamic Nuclear Polarization NMR, Diffuse Reflectance Infrared Fourier Transform Spectroscopy, and X-ray Photoelectron Spectroscopy
论文作者
论文摘要
由于其高表面积，高稳定性以及疏水性，周期性的介孔有机硅（PMO）材料代表了对水中环保化学过程的有希望的催化支持。我们在这里调查了使用苯连接器（PMOB）的PMO材料钙化如何允许其功能化。常规和动态核极化（DNP）增强的NMR光谱，弥漫性反射率红外傅立叶变换光谱和X射线光电学光谱证明，在450°C下的钙化会导致苯基桥氧化在苯乙烯中，但也导致了羧酸酸。还观察到酮，醛以及烯丙基和脂肪醇醇功能，但其量远低于羧酸的量。钙化还裂解了Si-C键。然而，N2吸附吸附测量，粉末X射线衍射和透射电子显微镜表明，钙化高达600°C的PMOB材料仍然显示出有序的中孔。我们表明，在室温下，在水中，pmOB的苯酚和羧酸功能性在450°C质合酸盐质合酸盐质合酸盐质碳酸盐（3-氨基丙基）咪唑（API）的NH2组，但未检测到API和钙化PMOB功能之间的共价键。
Owing to their high surface area, their high stability, and their hydrophobicity, periodic mesoporous organosilica (PMO) materials represent promising catalytic support for environmentally friendly chemical processes in water. We investigate here how the calcination of PMO material with benzene linkers (PMOB) allows its functionalization. Conventional and dynamic nuclear polarization (DNP)-enhanced NMR spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, and X-ray photoelectron spectroscopy prove that calcination at 450 °C results in the oxidation of phenylene bridges into (poly)phenols but also into carboxylic acids. Ketone, aldehyde, as well as allyl and aliphatic alcohol functionalities are also observed, but their amount is much lower than that of carboxylic acids. The calcination also cleaves the Si-C bonds. Nevertheless, N2 adsorption desorption measurements, powder X-ray diffraction, and transmission electron microscopy indicate that the PMOB materials calcined up to 600 °C still exhibit ordered mesopores. We show that the phenol and carboxylic acid functionalities of PMOB calcined at 450 °C protonate the NH2 group of 1-(3-aminopropyl)imidazole (API) in water at room temperature, but no formation of a covalent bond between API and the calcined PMOB functionalities has been detected.
