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首页> 外文期刊>American journal of applied sciences >Factor Analysis, Target Factor Testing and Model Designing of Aromatic Solvent Effect of the Formyl Proton Nuclear Magnetic Resonance Chemical Shift in Para Substituted Benzaldehydes
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Factor Analysis, Target Factor Testing and Model Designing of Aromatic Solvent Effect of the Formyl Proton Nuclear Magnetic Resonance Chemical Shift in Para Substituted Benzaldehydes

机译：对位取代苯甲醛中甲酰基质子核磁共振化学位移的芳族溶剂效应的因子分析，目标因子测试和模型设计

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Problem statement: The variations of formyl proton Chemical Shifts (CS) of p-substituted benzaldehydes in aromatic solvents were investigated. The validity of several physical solvent and empirical solvent scales was examined. Also, to predict dipolarity-polarizability (π~*) solvent scale for some aromatic solvents. Model designing was also achieved to rationalize the aromatic solvent effect on the formyl proton CS. Approach: The previously recorded formyl proton CS for p-X-benzaldehydes, with X were NMe_2, OMe, OC_3H_7, H, Br, CHO and NO_2 in benzene, toluene, p-xylene, m-xylene and mesitylene were subjected to Factor Analysis (FA). Target Factor Testing technique (TFT) was performed for several solvent scales namely: Unity, the intrinsic aromatic solvent induced shift of TMS (IASISTMS), f(n), f(d), (n~2-1)/(n~2+2), (d-1)/(d+2), E_T(30) and π~*. Iterative TFT was applied to predict unmeasured (π~*) solvent scale for ethyl benzene, n-butyl benzene, sec-butyl benzene, tert-butyl benzene and isopropyl benzene. Results: It has been found that two factors were responsible for the variation in the formyl proton CS. The unity, f(n), (n~2-1)/(n~2+2), IASISTMS, E_T(30) and π~* were real factors. Model designing of the formyl proton CS in benzene, toluene, p-xylene, m-xylene and mesitylene were achieved. The models with lowest root mean square error (RMSE) have shown that Unity is a consistent term. The other term was either IASISTMS or π~*. Iterative TFT predicted new π~* values for ethylbenzene, n-butylbenzene, sec-butylbenzene, tert-butylbenzene and isopropylbenzene respectively. Conclusion: FA has revealed that two real factors are responsible for the variation of formyl CS in benzene, toluene, p-xylene, m-xylene and mesitylene solvents. TFT has shown to be a powerful technique in predicting new values of the π~* solvent scale. Model designing for the formyl proton CS have revealed that the IASISTMS, π~* and Unity are the best empirical solvent scales and were better than any physical solvent scales in reproducing the formyl CS. The IASISTMS reflects the dipolarity-polarizabilty of the aromatic solvent. The cofactor of the solvent scale was found to correlate with the σ_p~+ substituent parameter.
机译：问题陈述：研究了芳族溶剂中对位取代苯甲醛的甲酰基质子化学位移（CS）的变化。检查了几种物理溶剂和经验溶剂规模的有效性。同样，可以预测某些芳香族溶剂的偶极极化率（π〜*）溶剂规模。还进行了模型设计，以合理化芳族溶剂对甲酰基质子CS的影响。方法：对先前记录的对X-苯甲醛的甲酰基质子CS（在苯，甲苯，对二甲苯，间二甲苯和均三甲苯中的X为NMe_2，OMe，OC_3H_7，H，Br，CHO和NO_2）进行因子分析（FA ）。目标因子测试技术（TFT）在以下几种溶剂规模上进行了测试：统一，固有的芳香族溶剂诱导的TMS转变（IASISTMS），f（n），f（d），（n〜2-1）/（n〜 2 + 2），（d-1）/（d + 2），E_T（30）和π〜*。应用迭代TFT来预测乙苯，正丁苯，仲丁苯，叔丁苯和异丙基苯的未测量（π〜*）溶剂规模。结果：已经发现有两个因素导致甲酰基质子CS的变化。 f（n），（n〜2-1）/（n〜2 + 2），IASISTMS，E_T（30）和π〜*是真实因素。实现了苯，甲苯，对二甲苯，间二甲苯和均三甲苯中甲酰基质子CS的模型设计。均方根误差（RMSE）最低的模型表明Unity是一个一致的术语。另一个术语是IASISTMS或π〜*。迭代TFT分别预测了乙苯，正丁基苯，仲丁基苯，叔丁基苯和异丙基苯的新π〜*值。结论：FA揭示了影响苯，甲苯，对二甲苯，间二甲苯和均三甲苯溶剂中甲酰基CS含量变化的两个真实因素。在预测π〜*溶剂垢的新值方面，TFT已被证明是一项强大的技术。甲酰基质子CS的模型设计表明，IASISTMS，π〜*和Unity是最佳的经验溶剂规模，并且在复制甲酰基CS方面优于任何物理溶剂规模。 IASISTMS反映了芳族溶剂的偶极极化性。发现溶剂垢的辅因子与σ_p〜+取代基参数相关。

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