Ground triplet pyrimidine-4,6-diyl bis(tert-butyl nitroxide) as a paramagnetic building block for metal–organic frameworks
作者:Yuta Homma、Atsushi Okazawa、Takayuki Ishida
DOI:10.1016/j.tetlet.2013.04.008
日期:2013.6
We synthesized pyrimidine-4,6-diyl bis(tert-butyl nitroxide) (pmbNO), and characterized as a biradical by means of ESR spectroscopy. The zero-field splitting parameters were |D|/hc = 2.52 × 10−2 cm−1 and |E|/hc = 2.34 × 10−3 cm−1 in frozen toluene at 100 K. Magnetic study clarified the presence of intramolecular ferromagnetic coupling with 2J/kB = +18.5(5) K in frozen toluene–ethanol. DFT calculation
我们合成了嘧啶-4,6-二基双(叔丁基氮氧化物)(pmbNO),并通过ESR光谱表征为双自由基。零场分裂参数为| D | / hc = 2.52×10 -2 cm -1和| E | / hc = 2.34×10 -3 cm -1在冷冻甲苯中于100K。磁性研究澄清了 在冷冻甲苯-乙醇中存在2 J / k B = +18.5(5)K的分子内铁磁耦合。DFT计算支持pmbNO的三重态。pmbNO与Cu(hfac)2的反应得到[Cu 3(pmbNO)2(hfac)4 ],并通过X射线晶体学分析确定结构。尽管配体被还原为阴离子基团,但已确认pmbNO可以作为刚性桥,并且氮氧化合物的氧原子可以连接金属离子。