Cp*₂Sc–OR (R = CMe₂CF₃, CMe(CF₃)₂, C(CF₃)₃, SiPh₃) was synthesized to determine how the alkoxide affects the quadrupole coupling (C_Q) obtained from solid-state ⁴⁵Sc{¹H} NMR spectroscopy. These alkoxides are characterized by large (>29 MHz) C_Q values, which are similar to C_Q values obtained for Cp*₂Sc–R (R = Me, Et, Ph) and Cp*₂Sc–X (X = F, Cl, Br, I) but significantly larger than C_Q values obtained for Cp*₂ScX(THF). The NMR properties from these alkoxides were used to understand the NMR properties of Cp*₂Sc-supported on silica partially dehydroxylated at 700 °C. This material contains two species from the solid-state ⁴⁵Sc{¹H} NMR spectra assigned to Cp*₂ScOSi≡ (5a) and Cp*₂Sc(OSi≡)O(SiO_x)₂ (5b). The solid-state ⁴⁵Sc{¹H} NMR spectrum of 5a is considerably broader than 5b, which relates to the magnitude of the quadrupolar coupling (C_Q) in these two different sites. Density functional theory (DFT) optimized structures of Cp*₂Sc–OR and small cluster approximations of 5a and 5b follow similar trends as the experimental C_Q values for this family of organoscandium complexes. Analysis of the origin of C_Q using DFT methods shows that σ- and π-bonding orbitals from the Sc–O bond in Cp*₂Sc–OR and 5a are major contributors to C_Q, whereas different orbitals contribute to C_Q in 5b. These studies show that quadrupolar solid-state NMR spectroscopy can distinguish between surface sites on partially dehydroxylated silica.

中文翻译：

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固态^45个Cp的钪NMR研究* ₂钪-OR（R = CME ₂ CF ₃，CME（CF ₃）₂，C（CF ₃）₃，SIPH ₃）及关系的Cp *的结构₂ SC-在部分脱羟基的二氧化硅上受支持的位点

合成了Cp * ₂ Sc–OR（R = CMe ₂ CF ₃，CMe（CF ₃）₂，C（CF ₃）₃，SiPh ₃），以确定醇盐如何影响由固相得到的四极偶合（C _Q）。态⁴⁵ Sc { ¹ H} NMR光谱。这些醇盐的特征在于大的（> 29兆赫）C _Q值，这是类似于C _Q值的Cp *获得₂钪-R（R =甲基，乙基，PH）1和Cp * ₂钪-X（X = F ，Cl，Br，I），但明显大于Cp * ₂获得的C _Q值ScX（THF）。来自这些醇盐的NMR特性用于了解在700°C下部分脱羟基的二氧化硅上负载的Cp * ₂ Sc的NMR特性。此材料含有从固体状态的两个物种⁴⁵钪{ ¹ H} NMR谱分配到的Cp * ₂ ScOSi≡（图5a）和的Cp * ₂钪（OSi≡）O（SIO _X）₂（图5b）。5a的固态⁴⁵ Sc { ¹ H} NMR光谱比5b宽得多，这与四极耦合的大小（C _Q）在这两个不同的网站中。Cp * ₂ Sc–OR的密度泛函理论（DFT）优化结构以及5a和5b的小簇近似值遵循与该有机scan络合物系列的实验C _Q值相似的趋势。C的原点的分析_Q使用DFT方法表明，从在的Cp *对SC-O键和σ-π-键轨道₂钪-OR和5a中的主要贡献者至C _Q，而不同的轨道有助于至C _Q在图5b。这些研究表明，四极固态NMR光谱可以区分部分脱羟基二氧化硅的表面位置。