associated C atoms of the ring. Finally, the radical-bridged complexes are single-molecule magnets, with relaxation barriers of Ueff = 50(1), 41(1), 38(1), and 33(1) cm–1 for R = OMe, Cl, NO2, and SMe2, respectively. Taken together, these results provide the first examination of how bridging ligand substitution influences magnetic coupling in semiquinoid-bridged compounds, and they establish design criteria
阐明桥联
配体取代与磁耦合强度之间的磁结构相关性对高温分子基磁性材料的开发至关重要。为此,我们报告了四氧杂
环戊二烯桥联的Fe II 2配合物[(Me 3 TPyA)2 Fe 2(RL)] n +(Me 3 TPyA =三(6-甲基-2-
吡啶基甲基)胺; n = 2:OMe LH 2 = 3,6-二甲氧基-2,5-二氢氧-1,4-苯醌,Cl LH 2 = 3,6-二
氯-2,5-二氢氧-1,4-苯醌,Na 2 [NO 2 L] = 3,6-二硝基-2,5-二氢羟基-1,4-苯醌
钠;n= 4:SMe 2 L = 3,6-双(二甲基ulf)-2,5-二氢xo-1,4-苯醌二亚基)和它们的单电子还原类似物。可变温度直流磁化率数据显示,氧化物种中的Fe II中心之间存在弱
铁磁超交换,交换常数为J = +1.2(2)(R = OMe,Cl)和+0.3(1)(R = NO 2,SMe 2)cm –1。相反,