A new N,N,O chelate for transition metal chemistry:: Fe5 and Fe6 clusters from the use of 6-hydroxymethyl-2,2′-bipyridine (hmbpH)
A new N,N,O chelate for transition metal chemistry:: Fe5 and Fe6 clusters from the use of 6-hydroxymethyl-2,2′-bipyridine (hmbpH)
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DOI：
10.1021/ic070174i
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发表时间：
2007-07-09
影响因子：
4.6
通讯作者：
Christou, George
中科院分区：
文献类型：
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作者：
Bagai, Rashmi;Abboud, Khalil A.;Christou, George
首次报道了6-羟甲基-2，2‘-联吡啶(HMBpH)阴离子在配位化学中作为络合物的应用。报道了四个新的Fe(III)簇合物[Fe5O2(OH)(O2CMe)(5)(HmBp)(3)](ClO4)(2)(1)和[Fe6O2(OH)(2)(O2cr)(6)(HmBp)(4)](NO3)(2)(R=Ph(2)，Me(3)，Bu-t(4)；hmBpH=6-羟甲基-2，2‘-联吡啶)的合成、晶体结构和磁化学表征。在无水乙醇中，Fe(ClO4)(3)、HMBpH和乙酸钠按1：1：4的比例反应得1，[Fe3O(O2CR)(6)(H2O)(3)](NO3)(R=Ph，Me，Bu-t)与HMBpH以1：1的比例在MeCN中反应得2-4。1的核心是一个[Fe-4(Mu(3)-O)(2)](8+)蝶形单元，通过O原子的桥联将第五个Fe原子连接到该蝴蝶单元上。2-4的核心还包括一个[Fe-4(Mu(3)-O)(2)](8+)蝴蝶单元，它的两侧通过O原子的桥联连接了一个Fe原子。在5.0-300K范围内，对配合物1-4进行了变温(T)和变场(H)固态直流和交流磁化(M)研究。数据拟合表明，1的基态自旋为S=5/2，而2-4的基态自旋为S=5。用矩阵对角化方法对M/Nµ(B)与H/T数据进行拟合，并仅包括轴向零场分裂(ZFS)，得到了1-4的轴向ZFS参数垂直棒D垂直棒分别为0.75、0.36、0.46和0.36 cm(-1)。
The initial use of the anion of 6-hydroxymethyl-2,2'-bipyridine (hmbpH) as a chelate in coordination chemistry is described. The syntheses, crystal structures, and magnetochemical characterization are reported of four new iron(III) clusters [Fe5O2(OH)(O2CMe)(5)(hmbp)(3)](ClO4)(2) (1) and [Fe6O2(OH)(2)(O2CR)(6)(hmbp)(4)](NO3)(2) (R = Ph (2), Me (3), Bu-t (4); hmbpH = 6-hydroxymethyl-2,2'-bipyridine). The reaction of Fe(ClO4)(3), hmbpH, and sodium acetate in a 1:1:similar to 4 ratio in EtOH gave 1, and the reaction between [Fe3O(O2CR)(6)(H2O)(3)](NO3) (R = Ph, Me, Bu-t) and hmbpH in a 1:1 ratio in MeCN gave 2-4, respectively. The core of 1 consists of a [Fe-4(mu(3)-O)(2)](8+) butterfly unit to which is attached a fifth Fe atom by bridging O atoms. The core of 2-4 also consists of a [Fe-4(mu(3)-O)(2)](8+) butterfly unit to which are attached an Fe atom on either side by bridging O atoms. Variable-temperature (T) and -field (H) solid-state DC and AC magnetization (M) studies were carried out on complexes 1-4 in the 5.0-300 K range. Fitting of the data revealed that 1 has an S = 5/2 ground state spin whereas 2-4 possess an S = 5 ground state. Fitting of the M/N mu(B) vs H/T data by matrix diagonalization and including only axial zero-field splitting (ZFS) gave values of the axial ZFS parameter vertical bar D vertical bar of 0.75, 0.36, 0.46, and 0.36 cm(-1) for 1-4, respectively.