Structural Elucidation of Amorphous Photocatalytic Polymers from Dynamic Nuclear Polarization Enhanced Solid State NMR
Structural Elucidation of Amorphous Photocatalytic Polymers from Dynamic Nuclear Polarization Enhanced Solid State NMR
复制标题
利用动态核极化增强固态 NMR 解析非晶光催化聚合物的结构
DOI：
10.1021/acs.macromol.7b02544
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发表时间：
2018-04-24
期刊：
影响因子：
5.5
通讯作者：
Blanc, Frederic
中科院分区：
文献类型：
--
作者：
Brownbill, Nick J.;Sprick, Reiner Sebastian;Blanc, Frederic
动态核极化 (DNP) 固态核磁共振 (NMR) 提供了一种显着增强 NMR 信号的最新方法，并且能够在一系列芘和苯单体单元交替的无定形光催化共聚物中获得详细的结构信息，而这些共聚物的结构无法通过其他光谱或分析技术可靠地确定。在高磁场（9.4-14.1 T）和低温（110-120 K）下获得了大的 C-13 交叉极化 (CP) 魔角旋转 (MAS) 信号增强，允许在自然丰度下采集 C-13 不充足的光谱，并促进完整的光谱分配，包括存在少量特定单体时。利用获得的高 C-13 信噪比来记录定量多接触 CP NMR 数据，用于确定聚合物的组成。这与单体进料比推定的芘：苯化学计量密切相关，从而能够理解它们的结构。
Dynamic nuclear polarization (DNP) solid-state nuclear magnetic resonance (NMR) offers a recent approach to dramatically enhance NMR signals and has enabled detailed structural information to be obtained in a series of amorphous photocatalytic copolymers of alternating pyrene and benzene monomer units, the structures of which cannot be reliably established by other spectroscopic or analytical techniques. Large C-13 cross-polarization (CP) magic angle spinning (MAS) signal enhancements were obtained at high magnetic fields (9.4-14.1 T) and low temperature (110-120 K), permitting the acquisition of a C-13 INADEQUATE spectrum at natural abundance and facilitating complete spectral assignments, including when small amounts of specific monomers are present. The high C-13 signal-to-noise ratios obtained are harnessed to record quantitative multiple contact CP NMR data, used to determine the polymers' composition. This correlates well with the putative pyrene:benzene stoichiometry from the monomer feed ratio, enabling their structures to be understood.