Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
J Am Chem Soc. 2009 Mar 11;131(9):3317-30. doi: 10.1021/ja808390a.
Static solid-state (35)Cl (I = (3)/(2)) NMR spectra of the organometallic compounds Cp(2)TiCl(2), CpTiCl(3), Cp(2)ZrCl(2), Cp(2)HfCl(2), Cp*(2)ZrCl(2), CpZrCl(3), Cp*ZrCl(3), Cp(2)ZrMeCl, (Cp(2)ZrCl)(2)mu-O, and Cp(2)ZrHCl (Schwartz's reagent) have been acquired at 9.4 T with the quadrupolar Carr-Purcell Meiboom-Gill (QCPMG) sequence in a piecewise manner. Spectra of several samples have also been acquired at 21.1 T. The electric field gradient (EFG) tensor parameters, the quadrupolar coupling constant (C(Q)) and quadrupolar asymmetry parameter (eta(Q)), are readily extracted from analytical simulations of the spectra. The (35)Cl EFG and chemical-shift tensor parameters are demonstrated to be sensitive probes of metallocene structure and allow for differentiation of monomeric and oligomeric structures. First-principles calculations of the (35)Cl EFG parameters successfully reproduce the experimental values and trends. The origin of the observed values of C(Q)((35)Cl) are further examined with natural localized molecular orbital (NLMO) analyses. The combination of experimental and theoretical methods applied to the model compounds are employed to structurally characterize Schwartz's reagent (Cp(2)ZrHCl), for which a crystal structure is unavailable. Aside from a few select examples of single-crystal NMR spectra, this is the first reported application of solid-state (35)Cl NMR spectroscopy to molecules with covalently bound chlorine atoms. It is anticipated that the methodology outlined herein will find application in the structural characterization of a wide variety of chlorine-containing transition-metal and main-group systems.
已在 9.4 T 下使用分段式四极相干（Carr-Purcell Meiboom-Gill，QCPMG）序列获取了有机金属化合物 Cp(2)TiCl(2)、CpTiCl(3)、Cp(2)ZrCl(2)、Cp(2)HfCl(2)、Cp*(2)ZrCl(2)、CpZrCl(3)、Cp*ZrCl(3)、Cp(2)ZrMeCl、(Cp(2)ZrCl)(2)mu-O 和 Cp(2)ZrHCl（施瓦茨试剂）的静态固态 (35)Cl（I = (3)/(2)）NMR 谱。部分样品的光谱也在 21.1 T 下获取。通过对光谱的分析模拟，可轻松提取电场梯度（EFG）张量参数、四极耦合常数（C(Q)）和四极不对称参数（eta(Q)）。(35)Cl EFG 和化学位移张量参数被证明是金属茂结构的敏感探针，可区分单体和齐聚物结构。(35)Cl EFG 参数的第一性原理计算成功地再现了实验值和趋势。进一步通过自然局域分子轨道（NLMO）分析研究了观察到的 C(Q)((35)Cl)值的起源。应用于模型化合物的实验和理论方法组合用于对结构特征未知的 Schwartz 试剂（Cp(2)ZrHCl）进行结构表征。除了少数单晶 NMR 谱的示例外，这是首次将固态 (35)Cl NMR 光谱应用于共价键合氯原子的分子。预计本文概述的方法将在各种含氯过渡金属和主族系统的结构表征中得到应用。
