13C and 207Pb NMR Chemical Shifts of Dirhodio- and Dilithioplumbole Complexes: A Quantum Chemical Assessment
13C and 207Pb NMR Chemical Shifts of Dirhodio- and Dilithioplumbole Complexes: A Quantum Chemical Assessment
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Dirhodio- 和 Dilithioplumbole 配合物的 13C 和 207Pb NMR 化学位移：量子化学评估
DOI：
10.1021/acs.inorgchem.9b02367
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发表时间：
2019
影响因子：
4.6
通讯作者：
Hada Masahiko
中科院分区：
文献类型：
--
作者：
Narayanan Radhika;Nakada Marisa;Abe Minori;Saito Masaichi;Hada Masahiko
采用密度泛函理论（DFT）和零阶正则近似DFT计算方法研究了具有含铅五元环的金属配位铅管的电子结构和13c和207pb核磁共振（NMR）化学位移，即单双铅管（[Rh-plumbole]−）、双铅管（Rh2-plumbole）和二硫铅管（Li2-plumbole）。[Rh-plumbole] -和Rh2-plumbole配合物的分子轨道相关图和扩展过渡态-自然轨道化学价分析表明，铅孔主要是π给体，Rh2-plumbole配合物以π给体为主。计算表明，在Rh2-plumbole配合物中，pb - c - α的核间距比在[Rh-plumbole]−中要长，这是由于Rh2-plumbole配合物中强π给体和弱π背给体的共同作用。计算得到的207pb和13c α核磁共振化学位移与实验趋势吻合较好。研究了相对论效应、官能团的作用、溶剂的作用以及精确交换外加剂对计算得到的207pb和13c α核磁共振化学位移的影响。配合物中207pb原子的核磁共振化学位移趋势来源于顺磁和自旋轨道的贡献。核磁共振成分分析表明，与li2 - plumplumole配合物相比，[rh - plumplumole]−和rh2 - plumplumole配合物的13c α原子的上移主要是由于顺磁项的减小。
Density functional theory (DFT) and zeroth-order regular approximation DFT calculations were performed to investigate the electronic structures and13C and207Pb nuclear magnetic resonance (NMR) chemical shifts of metal-coordinated plumboles, namely, monorhodioplumbole ([Rh–plumbole]−), dirhodioplumbole (Rh2–plumbole), and dilithioplumbole (Li2–plumbole), which have a five-membered ring containing lead. The molecular orbital correlation diagram and extended transition state–natural orbitals for chemical valence analysis of the [Rh–plumbole]−and Rh2–plumbole complexes showed that the plumbole is primarily a π-donor, with π-donation being dominant in the Rh2–plumbole complex. The present calculations show that the Pb–Cαinternuclear distances are longer in the Rh2–plumbole complex than in [Rh–plumbole]−because of the combined effect of strong π-donation and weak π-back-donation in the Rh2–plumbole complex. The calculated207Pb and13CαNMR chemical shifts agree with the experimental trends reasonably well. The influences of the relativistic effect, role of the functional, effect of the solvent, and dependence of the exact exchange admixture on the calculated207Pb and13CαNMR chemical shifts were investigated. The NMR chemical shift trend of the207Pb atom in the complexes originates from the paramagnetic and spin–orbit contributions. NMR component analysis revealed that the upfield shift of the13Cαatoms of the [Rh–plumbole]−and Rh2–plumbole complexes compared to that of the Li2–plumbole complex is mainly due to the decrease in the paramagnetic term.