Ershova Irina V, Smolyaninov Ivan V, Bogomyakov Artem S, Fedin Matvey V, Starikov Andrey G, Cherkasov Anton V, Fukin Georgy K, Piskunov Alexandr V
G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, 49Tropinina str., 603950 Nizhny Novgorod, Russian Federation.
Southern Scientific Center of Russian Academy of Sciences, 41 Chehova Ave., 344006 Rostov on Don, Russian Federation.
Dalton Trans. 2019 Jul 16;48(28):10723-10732. doi: 10.1039/c9dt01424a.
The new bis-o-iminobenzosemiquinonate nickel and cobalt complexes (imSQt-Bu)2M (M = Ni (1), Co (2)), where imSQ is a radical anion of 4,6-di-tert-butyl-N-(tert-butyl)-o-iminobenzoquinone, were synthesized and characterized in detail. The molecular structures of 1 and 2 have been established by single-crystal X-ray analysis. The metal atoms in 1 and 2 have a distorted tetrahedral environment, and the dihedral angles between the planes of two radical imSQ ligands are approximately 80° in both complexes. According to the structural and spectroscopy data along with magnetic susceptibility measurements the electronic structure of the complexes should be interpreted definitely as a high spin metal center NiII (d8, S = 1) in 1 and CoII (d7, S = 3/2) in 2 bonded with two o-iminobenzosemiquinonate radicals (Srad = 1/2). The strong antiferromagnetic metal-ligand spin interactions in both complexes lead to the observed St = 0 and St = 1/2 ground states in 1 and 2, respectively. The computational DFT UB3LYP/6-311++G(d,p) studies performed on 1 and 2 are in good agreement with experimental data. Complexes 1 and 2 have similar electrochemical properties. The electrochemical reduction of the complexes includes two quasi-reversible one-electron-transfer waves in the cathodic region corresponding to the formation of the anions [M(AP)2]2- and [(imSQ)M(AP)]1- (AP - dianion of 4,6-di-tert-butyl-N-(tert-butyl)-o-iminobenzoquinone), while in the anodic region only one quasi-reversible redox process was registered. All redox processes are shown to be ligand-based.
合成并详细表征了新型双 - o - 亚氨基苯半醌镍和钴配合物(imSQt - Bu)₂M（M = Ni (1)，Co (2)），其中imSQ是4,6 - 二叔丁基 - N - (叔丁基) - o - 亚氨基苯醌的自由基阴离子。通过单晶X射线分析确定了1和2的分子结构。1和2中的金属原子具有扭曲的四面体环境，并且在两种配合物中两个自由基imSQ配体平面之间的二面角约为80°。根据结构和光谱数据以及磁化率测量结果，配合物的电子结构应明确解释为1中的高自旋金属中心NiII（d⁸，S = 1）和2中的CoII（d⁷, S = 3/2）与两个o - 亚氨基苯半醌自由基（Srad = 1/2）键合。两种配合物中强烈的反铁磁金属 - 配体自旋相互作用分别导致在1和2中观察到的基态St = 0和St = 1/2。对1和2进行的计算DFT UB3LYP/6 - 311++G(d,p)研究与实验数据吻合良好。配合物1和2具有相似的电化学性质。配合物的电化学还原在阴极区域包括两个准可逆的单电子转移波，对应于阴离子[M(AP)₂]²⁻和[(imSQ)M(AP)]¹⁻（AP - 4,6 - 二叔丁基 - N - (叔丁基) - o - 亚氨基苯醌的二价阴离子）的形成，而在阳极区域仅记录到一个准可逆的氧化还原过程。所有氧化还原过程均显示为基于配体的。
