Through-Space Shielding Effects of Metal-Complexed Phenyl Rings
作者:William H. Miles、Michael J. Robinson、Samantha G. Lessard、Dasan M. Thamattoor
DOI:10.1021/acs.joc.6b01858
日期:2016.11.18
compounds containing a methylgroup in a 1,8-relationship to a metal-complexed phenyl ring bearing various substituents have been synthesized. The through-space shielding effects of the phenyl ring, as a function of substituent and complexing metal species, were monitored by observing the 1H NMR signal of the methylgroup located in the shielding zone of the ring. In all cases, the methyl signal was slightly
已经合成了几种与带有各种取代基的金属络合的苯环具有1,8关系的甲基的萘化合物。苯环的全空间屏蔽效应,作为取代基和络合金属物种的函数,通过观察1来监测。位于环的屏蔽区内的甲基的1 H NMR信号。在所有情况下,复合物中的甲基信号比未复合类似物中的甲基信号要弱得多。然而,对可用晶体结构的比较表明,与无金属的对应物相比,络合物中的苯环稍微更靠近萘甲基。X射线结构和DFT计算还显示,络合后苯环的碳-碳键平均长度略有延长。取代基对萘基甲基信号的影响很小,但在未络合的衍生物中可辨别,与我们先前的报道一致。相应的金属络合物中没有类似的趋势,例如铬系列,并且金属的作用似乎比取代基更重要。发现这些观察结果与NMR位移计算相符。
Heppert, Joseph A.; Morgenstern, Mark A.; Scherubel, Devin M., Organometallics, 1988, vol. 7, # 8, p. 1715 - 1723
作者:Heppert, Joseph A.、Morgenstern, Mark A.、Scherubel, Devin M.、Takusagawa, Fusao、Shaker, Mohammad R.
DOI:——
日期:——
Electronic effects in aromatic metal carbonyl complexes. II. Infrared and proton magnetic resonance spectra of substituted benzoic methyl ester tricarbonylchromium derivatives