Sarmiento Charlie V, Araujo Thamyres A, Reis Samira G, de Souza Mateus S, Allão Cassaro Rafael A, Novak Miguel A, Vaz Maria G F
Instituto de Física, Universidade Federal Do Rio de Janeiro Rio de Janeiro RJ Brazil.
Instituto de Química, Universidade Federal de Fluminense Niterói RJ Brazil
RSC Adv. 2019 Sep 25;9(52):30302-30308. doi: 10.1039/c9ra06506g. eCollection 2019 Sep 23.
In this contribution we report the synthesis, structure and magnetic properties of a family of lanthanide-based one dimensional compounds [Ln(hfac)(NaphNN)] , where Ln = Gd (1), Dy(2), Tb(3) and NaphNN is the nitronyl nitroxide (NN) radical 2-(1'-naphthalenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1-Imidazole-3-oxide-1-oxyl. The crystal structure reveals well isolated chains with a twofold helical axis. Magnetic investigation of the gadolinium(iii) chains showed relevant intrachain interactions between Gd-NN nearest neighbors and also Gd-Gd and NN-NN next nearest neighbors. The magnetic interaction parameters were obtained by fitting the data with a six membered ring model. The stronger antiferromagnetic interaction between NN radicals was confirmed by investigation of the mononuclear complex [Y(hfac)(NaphNN)] (4) with a similar coordination environment. The dynamic magnetic properties of 2 and 3 were investigated by using the temperature and frequency dependence of the magnetic susceptibility evidencing single chain magnet dynamics under a zero dc field.
在本论文中，我们报道了一系列基于镧系元素的一维化合物[Ln(hfac)(NaphNN)]的合成、结构和磁性，其中Ln = Gd (1)、Dy(2)、Tb(3)，NaphNN是硝酰基氮氧化物（NN）自由基2-(1'-萘基)-4,4,5,5-四甲基-4,5-二氢-1-咪唑-3-氧化物-1-氧基。晶体结构显示出具有二重螺旋轴的孤立链。对钆（iii）链的磁性研究表明，Gd-NN最近邻之间以及Gd-Gd和NN-NN次近邻之间存在显著的链内相互作用。通过用六元环模型拟合数据获得了磁相互作用参数。通过研究具有相似配位环境的单核配合物[Y(hfac)(NaphNN)] (4)，证实了NN自由基之间较强的反铁磁相互作用。通过研究磁化率的温度和频率依赖性，研究了2和3的动态磁性，证明了在零直流场下的单链磁体动力学。
