Biradical pincers involving two phenylene, biphenylene or terphenylene arms: Evidence for approach of two terminal nitroxides
作者:Rika Uesugi、Rina Takano、Takayuki Ishida
DOI:10.1016/j.tet.2024.133929
日期:2024.4
-CHCHO-(-CH)-(-CH)–N(O•)-Bu} ( and for = 2 and 3, respectively) were prepared, where -xylylenedioxy was chosen as a hinge and phenylene, biphenylene, and terphenylene were selected as an arm. The crystallographic analysis clarified the intramolecular proximity of the two radical groups was observed for , whereas and possess an open V-shape. In toluene solution ESR, five hyperfine splitting lines were
四种新的钳型双硝基氧,-CHCHO-(-CH)-N(O•)-Bu}(分别缩写为 和 for = 2 和 3;for = 1(已知))和 -CHCHO制备了-(-CH)-(-CH)–N(O·)-Bu}(和分别为= 2和3),其中选择-苯二甲氧基作为铰链,选择亚苯基、联亚苯基和三联苯作为一只手臂。晶体学分析阐明了观察到的两个自由基基团的分子内接近性,而 和 具有开放的 V 形。在甲苯溶液 ESR 中,在室温或更高温度下为每种化合物记录了 5 条超细分裂线。根据 ESR 模拟,反铁磁交换相互作用估计为 2/ = -0.05 至 -0.0002 K。交换相互作用的顺序如下:>>关于臂长和>关于位置异构体。在本研究中发现出现交替线宽的温度是一个方便的温标。