Imine or Enamine? Insights and Predictive Guidelines from the Electronic Effect of Substituents in H-Bonded Salicylimines
作者:R. Fernando Martínez、Esther Matamoros、Pedro Cintas、Juan C. Palacios
DOI:10.1021/acs.joc.0c00130
日期:2020.5.1
Imine and enamine bonds decorate the skeleton of numerous reagents, catalysts, and organic materials. However, it is difficult to isolate at will a single tautomer, as dynamic equilibria occur easily, even in the solid state, and are sensitive to electronic and steric effect, including π-conjugation and H-bonding. Here, using as model Schiff bases generated from salicylaldehydes and TRIS in a set of
Magnetic, high-field EPR studies and catalytic activity of Schiff base tetranuclear CuII2FeIII2 complexes obtained by direct synthesis
作者:Oksana V. Nesterova、Eduard N. Chygorin、Vladimir N. Kokozay、Volodymyr V. Bon、Irina V. Omelchenko、Oleg V. Shishkin、Ján Titiš、Roman Boča、Armando J. L. Pombeiro、Andrew Ozarowski
DOI:10.1039/c3dt51800k
日期:——
revealed that both compounds are based on the centrosymmetric tetranuclear core CuII2FeIII2(μ-O)6} where metal centres are joined by μ-O bridges from the deprotonated ligands forming a nonlinear chain-like arrangement. Variable-temperature (1.8–300 K) magnetic susceptibility measurements of 1 and 2 showed a decrease of the effective magnetic moment value at low temperature, indicative of antiferromagnetic
两种新颖的杂金属配合物[Cu 2 Fe 2(HL 1)2(H 2 L 1)2 ]·10DMSO(1)和[Cu 2 Fe 2(HL 2)2(H 2 L 2)2 ]·2DMF(2))已经使用铜粉末,铁(的露天反应制备II)氯化物和DMSO(1)或DMF(2)多齿席夫碱的溶液(H 4大号1,1 ; H4大号2, 2形成的)在原位从水杨醛( 1)或5-溴水杨醛( 2)和三(羟甲基)氨基甲烷。晶体学分析表明,这两种化合物均基于中心对称的四核核Cu II 2 Fe III 2(μ-O) 6 },其中金属中心通过去质子化配体的μ-O桥连接,形成非线性链状排列。1和2的可变温度(1.8–300 K)磁化率测量表示在低温下有效磁矩值减小,表明存在反铁磁耦合(J Cu–Fe / hc = -10.2 cm -1,J Fe–Fe / hc = -10.5 cm -1 in 1,J Cu–Fe / hc = -10
Tetracopper complexes with two-mode cubane-like Cu4O4 core from similar hydroxyl-rich salicylaldehyde Schiff bases: Structure and magnetic properties
作者:Bing Yang、Jiali Pan、Xianggao Meng、Jinge Cao、Yuyi Li、Fengping Xiao、Dongfeng Li
DOI:10.1016/j.poly.2016.02.042
日期:2016.5
The reaction of water-soluble hydroxyl-rich salicylaldehydeSchiff base ligands with the metal salt Cu(OAc) 2 ·H 2 O affords three novel tetracopper complexes via solvothermal method: [Cu 4 (H 2 L1) 4 ]·CH 3 OH( 1 ), [Cu 4 (HL2) 2 (Py) 2 (OAc) 2 ]( 2 ), [Cu 4 (HL3) 2 (Py) 2 (OAc) 2 ]( 3 ). The X-ray crystal structures reveal the cubane Cu 4 O 4 for complex 1 with μ 3 -alkoxo bridges and quasi-stepped
水溶性富羟基水杨醛席夫碱配体与金属盐Cu(OAc)2·H 2 O的反应通过溶剂热法制得三种新颖的四铜配合物:[Cu 4(H 2 L1)4]·CH 3 OH( 1),[Cu 4(HL2)2(Py)2(OAc)2](2),[Cu 4(HL3)2(Py)2(OAc)2](3)。X射线晶体结构揭示了具有μ3-烷氧基桥的配合物1的古巴铜4 O 4和带有2个由两个烷氧基和两个周边铜原子桥接的中心铜原子的2和3的准阶梯状古巴Cu 4 O 4。与中心铜原子通过另一个烷氧基氧桥接。随温度变化的磁测量结果表明1的立方芯内金属离子之间的主要铁磁相互作用为J 1 = +27.44 cm -1,J 2 = -0.21 cm -1(g = 2。
Structure and assembly studies of two planar Dy(<scp>iii</scp>) single molecule magnets with double relaxations