Novel copper(II) complexes with diazamesocyclic ligands functionalized by additional donor group(s): syntheses, crystal structures and magnetic properties
作者:Xian-He Bu、Miao Du、Lei Zhang、Zhi-Liang Shang、Ruo-Hua Zhang、Mitsuhiko Shionoya
DOI:10.1039/b007424l
日期:——
Copper(II) complexes with three diazamesocyclic ligands based on l,5-diazacyclooctane (DACO) bearing additional imidazole or phenol functional donor groups, 1,5-bis(imidazol-4-ylmethyl)- (L111), 1-(imidazol-4-ylmethyl)- (L222), and 1-(2-hydroxybenzyl)-1,5-diazacyclooctane (HL333), have been newly synthesized and characterized, and their structures determined by X-ray diffraction analyses. It has been revealed that with Cu(ClO4)2·6H2O L111 forms a mononuclear complex [CuL111Cl]ClO4·H2O 1, L222 forms a μ-Cl− bridged binuclear complex [CuL222Cl]2[ClO4]22, whereas HL333 forms a phenoxo-bridged binuclear complex [CuL33(H2O)]2[ClO4]23. Each CuII in the three complexes is five-coordinated in a distorted square-pyramidal environment. For the mononuclear complex 1 the Cl− anion is at the apical site, whereas for the μ-Cl−-bridged binuclear complex 2 the two bridging Cl− anions occupy both the axial and one equatorial position with Cu–Cl–Cu angle 88.81(5)° and intramolecular Cu ⋯ Cu separation 3.494(8) Å. In the phenoxo-bridged binuclear complex 3 the Cu–O–Cu bridging angle is 100.80(12)° and the intramolecular Cu ⋯ Cu distance is 3.0324(9) Å. Variable-temperature magnetic susceptibility measurements on the two binuclear complexes 2 and 3 in the range 4.2–300 K indicate a quite different magnetic intramolecular coupling between the binuclear copper(II) centers, from a weak ferromagnetic to a very strong antiferromagnetic coupling, with 2J = 1.16 (for 2) vs. −574 cm−1 (for 3), and the magneto-structural correlations are discussed in detail. The solution behaviors of the complexes have been further studied by UV/Vis and ESR techniques.
基于 l,5-二氮杂环辛烷(DACO)的三种重氮杂环配体的铜(II)配合物带有额外的咪唑或苯酚功能供体基团,即 1,5-双(咪唑-4-基甲基)-(L111)、1-(咪唑-4-基甲基)-(L222)和 1-(2-羟基苄基)-1,5-二氮杂环辛烷(HL333)、1-(imidazol-4-ylmethyl)- (L222) 和 1-(2-羟基苄基)-1,5-二氮杂环辛烷 (HL333),并通过 X 射线衍射分析确定了它们的结构。研究发现,L111 与 Cu(ClO4)2-6H2O 形成单核络合物 [CuL111Cl]ClO4-H2O 1,L222 形成 μ-Cl 桥双核络合物 [CuL222Cl]2[ClO4]22,而 HL333 则形成苯氧基桥双核络合物 [CuL33(H2O)]2[ClO4]23。这三种复合物中的每个 CuII 都是五配位的,处于畸变的方阵环境中。对于单核络合物 1,Cl-阴离子位于顶端位置,而对于μ-Cl-桥接双核络合物 2,两个桥接的 Cl-阴离子同时占据轴向和一个赤道位置,Cu-Cl-Cu 角为 88.在苯氧基桥联双核络合物 3 中,Cu-O-Cu 桥联角为 100.80(12)°,分子内 Cu ⋯ Cu 间距为 3.双核络合物 2 和 3 在 4.2-300 K 范围内的变温磁感应强度测量结果表明,双核铜(II)中心之间的分子内磁性耦合存在很大差异,从弱铁磁耦合到非常强的反铁磁耦合,2J = 1.16(2)与 -574 cm-1(3)之间的差异很大。通过紫外可见光/可见光和 ESR 技术进一步研究了这些复合物的溶液行为。