Novel oligoradicals and high spin formation
Novel oligoradicals and high spin formation
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新型寡自由基和高自旋形成
DOI：
10.1080/10587259508055278
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发表时间：
1995
影响因子：
0.7
通讯作者：
M. Baumgarten
中科院分区：
文献类型：
--
作者：
M. Baumgarten
本文研究了直链芳烯高自旋形成的正交排列和桥头位置分子轨道系数的变化。在具有非常小的MO系数但空间位阻也很小的2，21-联芘和对三芘中，发现双和三自由基阴离子处于低自旋基态，热激发三重态和四重态的能量分别高出100-1000 calmol-1。对于9，91-联蒽基，双自由基的形成是公认的，使得更高的低聚物已经带电，导致三聚体的S = 3/2，四聚体的S = 2，以及在聚合物中具有离散的S = 1，S = 3/2和S = 2状态的聚阴离子自由基，其中这种高度带电的材料变得不溶。由于在低温下偏离正交性的增加，基态也是低自旋的。在AEST= 60 cal/mol（S=1）、AEDQua = 120 Cal/mol（S=3/2）和AESQuin = 180 cal/mol（S=2）的情况下发现热活化的较高自旋多重性。在另一种方法中...
Abstract Orthogonal alignment and variation of the MO-coefficients at the bridgehead postion has been tested for high spin formation in directly linked arylenes. In 2,21-bipyrenyl and para-terpyrenyl possessing very small MO-coefficients but also small steric indrance bi- and triradicalanionss are found to be in low spin groundstate, with thermally excited triplet and quartet states 100-1000 calmol−1 higher in energy, respectively. For 9,91-bianthryl biradical formation is well established, such that higher oligomers have been charged resulting in a S = 3/2 for the trimer, a S = 2 for the tetramer and a polyanionradical with descrete S = 1, S = 3/2, and S = 2 states in the polymer, where this highly charged material becomes insoluble. The ground state is again low spin due to increased deviation from orthogonality at low temperatures. The thermally activated higher spin multiplicities are found with AEST= 60 cal/mol (S=1), AEDQua = 120 Cal/mol (S=3/2), and AESQuin = 180 cal/mol (s=2). In another approach ...