Rigid Core Anthracene and Anthraquinone Linked Nitronyl and Iminoyl Nitroxide Biradicals
作者:Handan Akpinar、John A. Schlueter、Rafael A. Allão Cassaro、Jonathan R. Friedman、Paul M. Lahti
DOI:10.1021/acs.cgd.6b00588
日期:2016.7.6
key role for inter-radical contacts for molecular packing. DiINs showed lower-dimensional dyad packing with disorder at the radical units: the conformationally more symmetrical diNNs gave staircase one-dimensional or brickwork two-dimensional lattices. Core anthracene unit stacking was only seen in two systems with bromine on the central anthracene ring: the (large) bromine occupies alternate side placement
报道了通过刚性并苯芯共轭蒽(A)和蒽醌(AQ)单元连接的双(硝基亚硝基氧)和双(亚氨基硝基氧)(diNN,diIN)双自由基的首次合成。计算模型预测在AQ连接的系统中分子内交换较弱,但A连接的双基具有与Borden-Davidson不相交模型一致的基态多重性。溶液电子自旋共振谱显示了自由基间交换耦合的三重态,除了显示孤立的自旋谱的2,6-AQ双自由基。A连接的双基自由基的晶体学表明,自由基间的接触对于分子堆积具有关键作用。DiINs显示较低维的二元堆积,在自由基单元处无序:构象更对称的diNNs形成楼梯的一维或砖砌二维晶格。仅在两个蒽环中央带有溴的系统中才能看到核心蒽单元的堆叠:(大)溴在diIN的二元组堆叠中占据交替的侧面位置,在diNN的链状堆叠中占据交替的侧面位置。2,7-A链系统的磁性表明,主要的铁磁分子内三重态单峰分裂(对于diNNs为24–28 K,对于diINs为8 K),以