A novel non-symmetrical polydentate Schiff base ligand 3-(2-[(1-methyl-3-oxobut-1-enyl)amino]ethyl}imino)butan-2-one oxime (H2L) comprising an oxime function among various donor sites yields neutral [NiIIL] and [CuIIL] complexes. The structural determination of [NiL] confirms the deprotonation of the oxime function. The deprotonated oxime oxygen atom can react with auxiliary complexes to give homo- and hetero-di- and tri-nuclear entities. The structural determination of a homodinuclear copper complex clearly shows the presence of the expected oxime bridge, along with an unexpected ketonic bridge between the two copper centres leading to a Cu[O,NO]Cu core. A moderate antiferromagnetic interaction is present in the di- and tri-nuclear copper complexes. A similar interaction is also observed in the heteronuclear complexes (CuIINiII and CuIIMnII) and, more surprisingly, in the heterodinuclear CuIICrIII entity. A generalization of the Cu[O,NO]Cu structure leads to a justification of these magnetic properties.
一种新型不对称多齿Schiff碱
配体3-(2-[(1-甲基-3-氧代丁-1-烯基)
氨基]乙基}亚
氨基)丁-2-酮
肟(H2L)在多个供体位点间包含
肟基功能,生成中性[NiIIL]和[CuIIL]配合物。[NiL]的结构确定确认了
肟基功能的去质子化。去质子化的
肟氧原子可以与辅助配合物反应,形成同核和异核的二核和三核实体。对同二核
铜配合物的结构确定清晰地显示出预期的
肟桥的存在,以及两个
铜中心间意外的酮桥,从而形成了Cu[O,NO]Cu核。在二核和三核
铜配合物中存在适度的反
铁磁相互作用。在异核配合物(CuIINiII和CuIIMnII)中也观察到了类似的相互作用,更令人惊讶的是,在异二核CuIICrIII实体中也出现了这种相互作用。对Cu[O,NO]Cu结构的推广为这些磁性特性提供了合理解释。