Reaction of Paramagnetic Synthon, Lithiated 4,4,5,5-Tetramethyl-4,5-dihydro-1<i>H</i>-imidazol-1-oxyl 3-oxide, with Cyclic Aldonitrones of the Imidazole Series
作者:Svyatoslav E. Tolstikov、Evgeny V. Tretyakov、Dmitry E. Gorbunov、Irina F. Zhurko、Matvey V. Fedin、Galina V. Romanenko、Artem S. Bogomyakov、Nina P. Gritsan、Dmitry G. Mazhukin
DOI:10.1002/chem.201602049
日期:2016.10.4
It was shown that dipole‐stabilized paramagnetic carbanion lithiated 4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazol‐1‐oxyl 3‐oxide can be attached in a nucleophilic manner to either isolated or conjugated aldonitrones of the 2,5‐dihydroimidazole 3‐oxide and 2H‐imidazole 1‐oxide series to afford adducts the subsequent oxidation of which leads to polyfunctional mono‐ and diradicals. According to XRD, at
结果表明,偶极稳定的顺磁碳负离子被锂化的4,4,5,5-四甲基-4,5-二氢-1 H-咪唑-1-氧代3-氧化物可以亲核方式与分离的或共轭的亚硝基硝基相连2,5-二氢咪唑3-氧化物和2 H-咪唑1-氧化物系列生成加合物,随后被氧化,生成多官能的一元基和双基。根据XRD,在所得顺磁性化合物的结晶过程中可以形成至少两个多晶型修饰,并且对于它们中的每一个,分子的几何参数是相似的。冷冻甲苯中的双自由基的EPR光谱具有复杂的线形,通过使用X射线衍射结构分析和以下一组参数可以很好地重现该线形:D = 14.9 mT,E = 1.7 mT;张量(14 N)= [0.260 0.260 1.625] mT的,对于氮氧自由基部分的(两个等效张量14 N)= [0.198 0.198 0.700] mT的,和克≈2.007。根据我们的DFT和从头算的计算,双自由基中的分子内交换非常弱,很可能是铁磁性的。