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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >A Solid-State NMR and Computational Study of Sodium and Potassium Tetraphenylborates:~(23)Na and ~(39)K NMR Signatures for Systems Containing Cation-pi Interactions
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A Solid-State NMR and Computational Study of Sodium and Potassium Tetraphenylborates:~(23)Na and ~(39)K NMR Signatures for Systems Containing Cation-pi Interactions

机译：含阳离子-π相互作用体系的四苯基硼酸钠和钾的固态NMR和计算研究：〜（23）Na和〜（39）K NMR特征

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摘要

Sodium and potassium tetraphenylborates were examined by solid-state ~(23)Na and ~(39)K NMR spectroscopy.Analyses of solid-state NMR spectra obtained at 4.70,11.75,and 19.60 T yielded the following ~(23)Na and ~(39)K NMR parameters:Na[BPH_4],|C_Q| = 1.24(+-)0.05 MHz,eta_Q = 0.0(+-)0.1,delta_(iso)=-45.6(+-)0.5 ppm,and OMICRON = 14(+-)2 ppm;K[BPH_4],|C_Q| = 1.32(+-)0.05 MHz,eta_Q = 0.0(+-)0.1,and d_iso =-92(+-)1 ppm.In both Na[BPh_4] and K[BPH_4],the electric field gradient and chemical shift tensors at the metal site are axially symmetric,in agreement with the crystallographic symmetry.Extensive quantum mechanical calculations were performed for Na[BPrh_4]] and K[BPh_4] as well as for a large number of model cation-pi systems containing Na~+and K~+ions and common aromatic compounds.Experimental and theoretical studies confirm that a highly shielded environment at the metal cation site is a characteristic feature for cation-pi interactions,making it useful as a NMR signature for identifying cation-pi interactions in proteins and nucleic acids.In this study,powder X-ray diffraction spectra for Na[BPh_4] and K[BPH_4] were also reported.
机译：用固态〜（23）Na和〜（39）K NMR光谱检查了四苯基硼酸钠和钾。在4.70、11.75和19.60 T下获得的固态NMR光谱分析得出以下〜（23）Na和〜 （39）K NMR参数：Na [BPH_4]，| C_Q | = 1.24（+/-）0.05 MHz，eta_Q = 0.0（+/-）0.1，delta_（iso）=-45.6（+/-）0.5 ppm，OMICRON = 14（+/-）2 ppm; K [BPH_4] | = 1.32（+-）0.05 MHz，eta_Q = 0.0（+-）0.1，d_iso = -92（+-）1 ppm。在Na [BPh_4]和K [BPH_4]中，电场梯度和化学位移张量金属上的位点是轴向对称的，与晶体对称性一致。对Na [BPrh_4]]和K [BPh_4]以及大量包含Na〜+和Na的模型阳离子-π体系进行了广泛的量子力学计算。实验和理论研究证实，金属阳离子位点处高度屏蔽的环境是阳离子-π相互作用的特征，使其成为NMR识别蛋白和蛋白质中阳离子-π相互作用的特征。在这项研究中，还报道了Na [BPh_4]和K [BPH_4]的粉末X射线衍射谱。

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