Zhong Chang, Zhao Min, Goslinski Tomasz, Stern Charlotte, Barrett Anthony G M, Hoffman Brian M
Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA.
Inorg Chem. 2006 May 15;45(10):3983-9. doi: 10.1021/ic052169p.
We report the synthesis and physical characterization of a new family of peripherally functionalized porphyrazine (pz) compounds, denoted 1[M1, M2], where metal ion M1 is incorporated into the pz core and metal ion M2 is bound to a salicylidene/picolinamide "hybrid" chelate built onto two nitrogen atoms attached to the pz periphery. The complexes 1[MnCl, Cu], 1[VO, Cu], and 1[Cu, Cu] have been prepared, and crystal structures show 1[MnCl, Cu] and 1[VO, Cu] to be isostructural. These complexes have been subjected to electron paramagnetic resonance and temperature-dependent magnetic susceptibility measurements. The variation of the ligand-mediated exchange splittings (delta) in these complexes is striking: delta/k(B) values for 1[MnCl, Cu] and 1[VO, Cu] are 22 and 40 K, respectively, while delta/k(B) for 1[Cu, Cu] is only 1 K. These coupling results are explained in terms of the relative orientation of the M1 and M2 orbitals and reflect the fact that the ligand set of M2 in the periphery is rotated in-plane by 45 degrees relative to the effectively coplanar pz ligand set of M1. The exchange couplings are essentially the same as those we determined for the Schiff base porphyrazines (pzs). Thus, the hybrid ligand has eliminated the dimerization found to occur when Cu(II) is bound to the periphery of bis(picolinamido) pzs and has created a more robust ligand system than the Schiff base pzs while retaining the ability they show to promote spin coupling between M1 and M2.
我们报道了一类新型的周边功能化卟嗪（pz）化合物的合成及物理特性，该化合物记为1[M1, M2]，其中金属离子M1嵌入到pz核中，金属离子M2与基于连接在pz周边两个氮原子上的水杨醛/吡啶甲酰胺“杂化”螯合物相连。已制备出配合物1[MnCl, Cu]、1[VO, Cu]和1[Cu, Cu]，晶体结构表明1[MnCl, Cu]和1[VO, Cu]为同构体。对这些配合物进行了电子顺磁共振和温度依赖磁化率测量。这些配合物中配体介导的交换分裂（δ）变化显著：1[MnCl, Cu]和1[VO, Cu]的δ/k(B)值分别为22 K和40 K，而1[Cu, Cu]的δ/k(B)仅为1 K。这些耦合结果根据M1和M2轨道的相对取向进行了解释，反映出周边M2的配体组相对于M1有效共面的pz配体组在平面内旋转了45度这一事实。交换耦合与我们测定的席夫碱卟嗪（pzs）的耦合基本相同。因此，杂化配体消除了Cu(II)与双（吡啶甲酰胺）pzs周边结合时发生的二聚化现象，并且创建了一个比席夫碱pzs更稳定的配体体系，同时保留了它们促进M1和M2之间自旋耦合的能力。
