Abstract Treatment of (3,3′-bis-((2,6-dimethylphenyl)-imino)methyl)-(1,1′)-biphenyl-2,2′-diol) (H2L2) and (3,3′-bis-((2-methoxyphenyl))imino)methyl)-(1,1′)-biphenyl-2,2′-diol) (H2L3) with excess [Cu2(OAc)4(H2O)2] in the presence of triethylamine afforded new trinuclear complexes [Cu(3,3′-bis-((R)-iminomethyl)-(1,1′)-biphenyl-2,2′-dioxo)]3 [R = 2,6-Me2C6H3 (3e) and R = 2- OMeC6H3(4e)] respectively. The resulting complexes were characterized by elemental analysis, magnetic susceptibility, EPR, UV–Vis, IR, CV and Single crystal X-ray diffraction analysis. The magnetic susceptibility study of 3e and 4e was performed in the 5–300 K and revealed the existence of antiferromagnetic interaction in both complexes. The experimental data could be satisfactorily reproduced using an isotropic exchange model, H = -J (S1S2 + S2S3 + S1S3), yielding as best fit parameters: J = −15 cm−1, g = 1.99 for 3e and J = −18 cm−1, g = 1.99 for 4e. Both complexes have an angular C2/c-symmetric trinuclear core and each Cu(II) ion is in similar environments coordinated to two (O, N) donor sets as revealed from single-crystal X-ray diffraction studies. The coordination geometry can best be described as distorted square planar which could be judged using the τ4 index, τ4 = 360 – (α + β)/141°, where α and β are the two largest angles subtended by the ligand donor atoms in the four-coordinate complex. The average indexes for 3e and 4e were found to be 0.42 and 0.43 respectively, signifying a considerable distortion from an idealized square planar, D4h geometry (τ4 = 0.0) or idealized tetrahedral, Td geometry (τ4 = 1.0). The average Cu⋯Cu distance between closest copper(II) ions in the complex 3e is 4.48 A. On the other hand, the single crystal X-ray analysis showed that each of the three Cu(II) centers in complex 4e is strongly tetracoordinated to two N and two O atoms & weakly to two O atoms of the methoxy groups of the ligand, N,N′,O,O′-3, 3′-bis ((2-methoxyphenyl)-iminomethyl)-[1, 1′-biphenyl]-2, 2′-diol (H2L3). Generally, Cu−N & Cu−O bond lengths are (1.983–1.994) & (1.882–1.893) respectively, comparable to similar systems.

中文翻译：

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具有双酚基双核配体的新型三核铜 (II) 配合物的合成、晶体结构和磁性

摘要 (3,3'-双-((2,6-二甲基苯基)-亚氨基)甲基)-(1,1')-联苯-2,2'-二醇) (H2L2) 和 (3,3' -双-((2-甲氧基苯基))亚氨基)甲基)-(1,1')-联苯-2,2'-二醇) (H2L3) 与过量 [Cu2(OAc)4(H2O)2] 在存在下三乙胺得到新的三核配合物 [Cu(3,3'-bis-((R)-iminomethyl)-(1,1')-biphenyl-2,2'-dioxo)]3 [R = 2,6-Me2C6H3 (3e) 和 R = 2-OMeC6H3(4e)]。所得配合物通过元素分析、磁化率、EPR、UV-Vis、IR、CV 和单晶 X 射线衍射分析进行表征。3e 和 4e 的磁化率研究是在 5-300 K 下进行的，揭示了两种配合物中存在反铁磁相互作用。使用各向同性交换模型可以令人满意地再现实验数据，H = -J (S1S2 + S2S3 + S1S3)，产生最佳拟合参数：J = -15 cm-1，3e 的 g = 1.99 和 4e 的 J = -18 cm-1，g = 1.99。两种配合物都有一个有角的 C2/c 对称三核核心，每个 Cu(II) 离子都处于与两个 (O, N) 供体组协调的相似环境中，如单晶 X 射线衍射研究所示。配位几何最好被描述为扭曲的方形平面，可以使用 τ4 指数来判断，τ4 = 360 – (α + β)/141°，其中 α 和 β 是配体供体原子所对的两个最大角度四坐标复合体。发现 3e 和 4e 的平均指数分别为 0.42 和 0.43，表明理想化方形平面 D4h 几何（τ4 = 0.0）或理想化四面体 Td 几何（τ4 = 1.0）存在相当大的失真。配合物 3e 中最近的铜 (II) 离子之间的平均 Cu⋯Cu 距离为 4。48 A. 另一方面，单晶 X 射线分析表明，配合物 4e 中的三个 Cu(II) 中心中的每一个都与两个 N 和两个 O 原子强四配位，而与甲氧基的两个 O 原子弱配位。配体 N,N',O,O'-3, 3'-双 ((2-甲氧基苯基)-亚氨基甲基)-[1, 1'-联苯]-2, 2'-二醇 (H2L3)。通常，Cu-N 和 Cu-O 键长分别为 (1.983–1.994) 和 (1.882–1.893)，与类似系统相当。