Breaking the Semi-Quinoid Structure: Spin-Switching from Strongly Coupled Singlet to Polarized Triplet State
作者:Prince Ravat、Yoshio Teki、Yoshikazu Ito、Elena Gorelik、Martin Baumgarten
DOI:10.1002/chem.201403338
日期:2014.9.15
unprecedented strong intramolecular magnetic exchange interaction of 2 J/kB=1185 K operating over a distance of 10 Å. Structural transformations with the activation energy of ΔEeq=949 K were observed by varying the temperature, from more quinoid structure at low temperature to more biradicaloid structure at higher temperature. Moreover, this molecule undergoes a transient spin transition from singlet to polarized
发现2,7-TMPNO(4,5,9,10-四甲氧基py -2,7-双(叔丁基硝基氧))以半醌形式存在,其空前的强分子内磁交换相互作用为2 J / k B = 1185 K的工作距离为10Å。通过改变温度,观察到活化能为ΔE eq = 949 K的结构转变,从低温下的更多醌型结构到高温下的更多双自由基型结构。此外,在通过TREPR光谱法揭示的光激发下,该分子经历从单重态到极化三重态的瞬时自旋转变。自旋哈密顿量参数确定为S = 1,g = 2.0065,D通过使用混合本征场/精确对角化方法进行光谱模拟,得出= -0.0112 cm -1和E = -0.0014 cm -1。