Four new pincer-type bisnitroxides, -CH{CHO-(-CH)-N(O•)-Bu} (abbreviated as and for = 2 and 3, respectively; for = 1 (known)), and -CH{CHO-(-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 recorded for every compound at room temperature or higher. The antiferromagnetic exchange interaction is estimated as 2/ = −0.05 to −0.0002 K from ESR simulation. The orders of the exchange interactions are as follows: > > regarding the arm lengths and > regarding the positional isomers. The temperature at which alternating linewidths appeared was found to be a convenient temperature scale in this study.

中文翻译：

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涉及两个亚苯基、联亚苯基或三联苯臂的双自由基钳：两个末端硝基氧接近的证据

四种新的钳型双硝基氧，-CH{CHO-(-CH)-N(O•)-Bu}（分别缩写为 和 for = 2 和 3；for = 1（已知））和 -CH{CHO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。