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首页> 外文期刊>RSC Advances >A successful DFT calculation of carbon-13 NMR chemical shifts and carbon–fluorine spin–spin coupling constants in (η6-fluoroarene)tricarbonylchromium complexes
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A successful DFT calculation of carbon-13 NMR chemical shifts and carbon–fluorine spin–spin coupling constants in (η6-fluoroarene)tricarbonylchromium complexes

机译：在（η6-氟甲醛）三羰基溴络合物中的碳-13 NMR化学位移和碳氟自旋偶联常数的成功DFT计算

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摘要

Carbon-13 isotropic shielding constants and carbon–fluorine spin–spin coupling constants for fluorobenzene ( 1 ), 3-dimethylaminofluorobenzene ( 2 ) and 4-dimethylaminofluorobenzene ( 3 ) as well as for their tricarbonylchromium complexes ( 3–6 ) have been calculated using DFT method with B3LYP and/or BHandH functionals and 6-311++G(2d,p) basis set. In the case of the complexes, the calculations have been performed for two expected orientations of the tricarbonylchromium tripod with respect to the benzene ring. It has been found that, when using B3LYP functional, the experimental ~(13) C NMR chemical shifts for all the investigated compounds can be well reproduced, provided that for the complexes the populations of conformers are adjusted during the experiment/theory correlation. The population parameters determined this way follow perfectly the expectations based on the literature knowledge of the effects of the benzene ring substituents. The calculations with BHandH functional have not been able to reproduce the ~(13) C NMR chemical shifts of carbonyl carbons in tricarbonylchromium complexes. On the other hand, BHandH is a functional of choice in calculations of carbon–fluorine spin–spin coupling constants. All such constants, including the through-space coupling constants between the carbonyl carbons and fluorine, have been reproduced very well. This last coupling constant has been calculated for various relative orientations of carbonyl and C–F bond and a strong angular dependence of this constant has been found.
机译：氟苯（1），3-二甲基氨基氟苯（2）和4-二甲基氨氟苯（3）以及它们的三羰基溴聚合物（3-6）的碳-13各向同性屏蔽常数和碳氟旋转旋转常数（3-6）具有B3LYP和/或BHANDH功能的DFT方法和6-311 ++ G（2D，P）的基础集。在配合物的情况下，已经针对三羰基摩擦三架相对于苯环的两种预期取向进行了计算。已经发现，当使用B3LYP功能时，可以良好地再现实验〜（13）C NMR化学位移，只要对复合物进行络合物，在实验/理论相关期间调整群体的群体。通过基于苯环取代基的作用的文献知识，通过对苯环取代基的影响的文献知识完美地确定了人口参数。使用BhandH功能的计算尚未能够在三羰基溴硅酸盐中再现羰基碳的〜（13）C NMR化学位移。另一方面，B Handh是在计算碳氟自旋旋转偶联常数的选择中的功能。所有这样的常数，包括羰基碳和氟之间的通孔耦合常数已被再现。已经针对羰基和C-F键的各种相对取向计算了最后耦合常数，并且已经发现了这种常数的强角度依赖性。

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