Kinetic Trapping Effects in Amphiphilic Iron(II) Spin Crossover Compounds.
Kinetic Trapping Effects in Amphiphilic Iron(II) Spin Crossover Compounds.
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DOI：
10.1021/acs.inorgchem.8b02763
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发表时间：
2019-01
影响因子：
4.6
通讯作者：
Johannes Weihermüller;Stephan Schlamp;B. Dittrich;Birgit Weber
中科院分区：
文献类型：
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作者：
Johannes Weihermüller;Stephan Schlamp;B. Dittrich;Birgit Weber
本文报道了四种新的以席夫碱类两亲赤道配体(L)和二甲氨基吡啶(DMAP)或4，4‘-联吡啶(BPY)为轴向配体的铁络合物的合成。其中三个配合物[FeL(DMAP)2]1，[FeL(DMAP)(MeOH)0.5]·MeOH2和[FeL(Bipy)]n3具有铁(II)中心，其中两个具有N4O2配位球(1和3)的配合物具有自旋交叉活性。两者都表现出热滞(10K，t1/2=131K；23K，t1/2=161K)，其中宽度取决于测量所用的速度。此外，在这两种情况下，高自旋态都被快速冷却捕获，TTIESST被确定为121K(1)和101K(3)。以DMAP为轴向配体的三种不同配合物(1S，2和[μ-O-{FeL}2(DMAP)]4)均获得了适合于X-射线结构分析的单晶。配合物1S在轴向位置有两个DMAP分子，而另外两个结构是通过甲醇交换DMAP配体和铁(II)中心被氧化为铁(III)形成双核μ-O-配合物。这三种络合物都是在有氧/无氧条件下在相似的反应条件下得到的，并且三种结构都表明在填料中形成了类脂层状排列。
In this work, the synthesis of four new iron complexes with a Schiff base-like amphiphilic equatorial ligand (L) and dimethylaminopyridine (dmap) or 4,4'-bipyridine (bipy) as axial ligands is reported. Three of the complexes ([FeL(dmap)2] 1, [FeL(dmap)(MeOH)0.5]·MeOH 2, and [FeL(bipy)] n 3 have an iron(II) center, and two of those with an N4O2 coordination sphere (1 and 3) are spin crossover active. Both exhibit a thermal hysteresis (10 K with T1/2 = 131 K for 3 and 23 K with T1/2 = 161 K for 1) where the width depends on the velocity used for the measurement. Additionally, in both cases, the high spin state is trapped by rapid cooling, and a TTIESST was determined to be 121 K (1) and 101 K (3). Single crystals suitable for X-ray structure analysis were obtained for the three different complexes with dmap as axial ligand (1S, 2, and [μ-O-{FeL}2(dmap)] 4). The complex 1S has two dmap molecules in axial position, while the other two structures were obtained for a complex where a dmap ligand is exchanged by methanol and one where the iron(II) center is oxidized to iron(III) to form a dinuclear μ-O-complex. All three complexes were obtained under similar reaction conditions in the presence/absence of oxygen, and all three structures show the formation of lipid layer-like arrangements in the packing.