摘要
本文合成出双核桥联络合物μ-Pyz[Cu(IDA)]_2,并培养出单晶。用四园衍射仪测定了晶体结构。属单斜晶系,空间群P2_1/c,晶胞参数:α=11.725(3)A;b=6.630(2)A,c=14.089(5)A,β=107.9(2)~0;Z=2;R=0.080。亚胺基二乙酸(IDA)的N_1,O_1,O_3原子是以三齿径式与Cu(Ⅱ)离子配位,以及吡嗪环上的N_2原子构成赤道配位平面,在轴向上下是与两个H_2O分子的O原子构成一个拉伸畸变的八面体配位场。吡嗪的两个N原子把两个Cu(IDA)配合物桥联起来。吡嗪环平面与铜(Ⅱ)离子的赤道配位平面成47°角。ESR实验证明:这两个Cu(Ⅱ)离子上的末偶电子,通过吡嗪环进行微弱的磁交换互作用。EHMO计算结果表明:吡嗪的α_R和b_(1R)轨道,对传递磁交换作用有贡献。α_R轨道是通过α—交换机理传递磁交换作用,而b_(1R)轨道是通过π—交换机理传递磁交换作用,由于吡嗪与Cu(Ⅱ)离子的配位能力不强,以致在该配合物中吡嗪桥传递磁交换作用也是微弱的。
A bridged binuclear complex μ-Pyz[Cu(IDA)]_2 had been synthesized, and its single crystal structure had determined in this paper The erystal belong to monoclinic system, and P2_1 / c space group. Unit cell Parameters are: a = 11.725 (3) A; b = 6.630 (2) A; c = 14.089 (5) A; β = 107.9 (2) and Z= 2. Final unweighted factor R = 0.080. The N (1), O (1), O (3) atoms of iminodiacetic arid as tridentiform meridionally coordinate with Cu (Ⅱ) ion and form the equatorial coordination plane with N (2) atom of Pyrazine. Two H_2O molecules coordinate to cu (Ⅱ) ion in axial direction, and formed a drawing distortional octahedral ligand field. The two Cu (IDA) complexes is bridged by pyrazine. The bihedral angle between the plane of pyrazine ring and the equatorial coordination plane is 47 degree. ESR measurement shows a weak magnetic exchange interaction between two Cu (Ⅱ) ions through pyrarine bridge. EHMO calculation shows that a_r and b_(IR) orbitals of pyrarine are mian contributions to transportation of magnetic exchange interaction. The a_R orbital tyansporte the magnetic ex- change interaction passing through σ-exchange mechanism, and the b_(IR) orbital passing through π-exchange mechanism. Owing to pyrazine coordination with Cu (Ⅱ) ion is not too strong, so that the pyrazine bridge transporting magnetic exchange intcraction also is weak in this complex.
基金
国家自然科学基金
