Pseudohalogenido complexes of iron-2,2′-bidipyrrins
Pseudohalogenido complexes of iron-2,2′-bidipyrrins
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DOI：
10.1142/s1088424612500538
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发表时间：
2012-05-01
影响因子：
1.5
通讯作者：
Pietzonka, Clemens
中科院分区：
文献类型：
--
作者：
Broering, Martin;Koehler, Silke;Pietzonka, Clemens
八乙基-2，2‘-联吡咯与叠氮、氰酸盐、硫氰酸盐、硒氰酸盐等阴离子的配体交换反应，使八乙基-2，2’-联吡咯的氯化铁(III)络合物转变为一系列的假卤化物络合物。所有新的配合物都显示出预期的轴向配体与铁(III)中心的N配位。在固态，四个物种都表现出中间自旋(S=3/2)基态，随着温度的升高，具有最小配位场强度的成员，即氰基和叠氮衍生物，其高自旋(S=5/2)贡献逐渐增加。在溶液中，质子核磁共振，特别是红外光谱研究支持对整个系列在常温下的高自旋态的解释。因此，自旋态对结晶态或溶解态的依赖性类似于以前发现的类似系列卤化物的衍生物。在二氯甲烷溶液中，硫氰酸盐和硫氰酸根的络合物对空气氧化非常敏感，仅有的两种分离产物生成了氧杂环己烷和硫氰酸根的络合物。这些配合物在固体和溶液中都表现出S=3/2的自旋态，它们的结构分析证明了线性拟卤化物离子与铁(III)中心金属之间存在预期的强p键。
The chlorido iron(III) complex of octaethyl-2,2'-bidipyrrin has been transformed to a series of pseudohalide complexes by ligand exchange reactions with azide, cyanate, thiocyanate and selenocyanate anions. All new complexes show the expected N-coordination of the axial ligand to the iron(III) center. In the solid state, all four species display an intermediate spin (S = 3/2) ground state, with a gradual increase of a high spin (S = 5/2) contribution at elevated temperatures for the members with the smallest ligand field strengths, i.e. the cyanato and the azido derivatives. In solution, proton NMR, and in particular IR spectroscopic studies support the interpretation of a high-spin state at ambient temperature throughout the series. The dependency of the spin state on the crystalline or dissolved state thus resembles that found for a similar series of halide derivatives before. In dichloromethane solution, the thiocyanato and selenocyanato complexes are very sensitive to aerial oxidation, forming oxacorrole and thiacorrole complexes as the only isolated products. These complexes show a S = 3/2 spin state in the solid as well as in solution, and their structural analyses prove the expected strong p-binding of the linear pseudohalide ion to the iron(III) central metal.