terpyridine; tphz, tetrapyridophenazine) were tailored by changing the oxidation state of the pyrazine-based bridging ligand. While its neutral form mediates a weak antiferromagnetic (AF) coupling between the two S = 1 Ni(II), its reduced form, tphz•-, promotes a remarkably large ferromagnetic exchange of +214(5) K with Ni(II) spins. Reducing twice the bridging ligand affords weak Ni-Ni interactions, in marked
双核配合物 [(tpy)Ni(tphz)Ni(tpy)] n+(n = 4、3 和 2;tpy,三联
吡啶;tphz,四
吡啶并
吩嗪)中的分子内磁相互作用是通过改变
吡嗪的氧化态来调整的——基于桥接
配体。虽然它的中性形式介导了两个 S = 1 Ni(II) 之间的弱反
铁磁 (AF) 耦合,但其还原形式 tphz•- 促进了 +214(5) K 与 Ni(II) 自旋的非常大的
铁磁交换. 减少两倍的桥接
配体提供弱的 Ni-Ni 相互作用,与 Co(II) 类似物形成鲜明对比。通过仔细检查所涉及的轨道,这些实验结果提供了对通过芳香桥
配体控制磁性交换强度和符号的因素的清晰理解,