铁在自然界中含量丰富，是许多金属酶的重要组成元素，在生物催化中起重要作用。铁卟啉在自然界中广泛存在，在生物体的新陈代谢过程中发挥着重大作用，例如血红素，细胞色素P450等。其中，血红素是一类典型的铁卟啉化合物，由一个平面卟啉配体与高自旋铁(II)中心配位，具有S = 2的自旋态。介导O₂活化是铁卟啉及其衍生物的一项重要功能。化学家们对O₂活化过程中产生的“铁-氧”中间体进行了大量的研究。这些“铁-氧”中间体的高活性，吸引着化学家们对“铁-烷氧”配合物的研究兴趣。因此，设计合成低配位高自旋的铁(II)配合物，研究它们的结构和反应性质具有重要意义。
       二吡咯可看作卟啉化合物的半个结构单元，具有独特的光物理性质，易于合成。近期，单（二吡咯）基铁配合物被报道用于催化Csp³-H键胺化反应。而有关双（二吡咯）铁配合物性质方面的研究报道甚少。
       基于此，本论文围绕双（二吡咯）配体螯合的不饱和高自旋铁配合物的合成、结构和反应性质研究展开工作，主要内容如下：
       1. 设计合成双（二吡咯）螯合的高自旋铁(II)配合物(dipyrrin)2Fe（1）。该配合物具有S = 2的自旋态和扭曲四面体构型，能与多种小分子（如NH₃，2,2ꞌ-联吡啶，CO等）发生配位反应。通过(dipyrrin)₂Fe与2,4,6-三叔丁基苯氧自由基的单电子氧化反应，生成五配位的高自旋铁(III)烷氧配合物(dipyrrin)₂Fe-OAr^tBu₃（2）。SQUID磁性测量表明，配合物2具有S = 5/2的自旋态。此外，我们还设计合成了氧桥或硫桥的多核二吡咯铁配合物[(dipyrrin)Fe]₂(μ-O^tBu)₂（3）和[(dipyrrin)Fe]₃(μ-SAr)₃（4）。通过X射线单晶衍射和紫外可见吸收光谱等手段对所得金属配合物的结构和性质进行了表征。
       2. 我们发现，高自旋“铁(III)-烷氧”配合物(dipyrrin)₂Fe-OAr^tBu₃（2）能高效促进ε-己内酯聚合。在0.1 mol%的催化剂负载量下，生成分子量高、分子量分布窄（Mn = 84.87 × 10³ g/mol，PDI = 1.25）的聚己内酯。动力学研究表明，ε-己内酯聚合反应符合一级动力学规律。配合物2对δ-戊内酯也有较高的催化活性。在0.25 mol%的催化剂负载量下，能产生分子量为和分子量分布较窄的聚戊内酯（Mn = 49.88 × 10³ g/mol，PDI = 1.50），控制聚合效果良好。基于配合物2对两种单体高的催化活性，我们将ε-己内酯和δ-戊内酯进行一锅法共聚反应，得到具有一定弹性和黏性的高聚产物（Mn = 115.29 × 10³ g/mol，PDI = 1.77）。

       Abundant in nature, iron is an important component of many metal enzymes and plays an important role in biocatalysis. Iron porphyrins exist widely in nature and play an important role in the metabolism of organisms, such as heme and cytochromeP450. Heme is a typical class of iron porphyrin compounds, consisting of a planar porphyrin ligand with a high-spin iron(II) center coordination, with a spin state of S = 2. Mediating O₂ activation is an important function of iron porphyrin and its derivatives. Chemists have done a great deal of work on the "iron-oxygen" intermediates produced during O₂ activation. The high activity of these "iron-oxygen" intermediates has attracted the interest of chemists in the research of "iron-alkoxy" complexes. Therefore, it is of great significance to design and synthesize low coordination and high-spin iron(II) complexes and study their structure and reaction properties.
       Dipyrrin can be regarded as half structural unit of porphyrin compound, which has unique photophysical properties and is easy to synthesize. Recently, mono(dipyrrin) iron complexes were reported to be used in catalytic Csp³-H key amination reaction. In contrast, the properties of bis(dipyrromethene) iron complexes are rarely reported.
Based on this, the paper focuses on the synthesis, structure and reaction properties of unsaturated high-spin iron complexes bearing bis(dipyrromethene) ligands. The main contents are as follows: 
       1. A bis(dipyrromethene) chelated high-spin iron(II) complex (dipyrrin)₂Fe (1) has been synthesized. Complex 1 has a S = 2 spin state and twisted tetrahedral geometry and can react with a variety of small molecules (such as NH3, 2, 2ꞌ - pyridine, CO, etc.). (dipyrrin)₂Fe-OAr^tBu₃ (2) was obtained by the single electron oxidation reaction of (dipyrrin)₂Fe with 2,4,6-tritert-butylphenoxy radical. SQUID magnetic tests show that complex 2 has a S = 5/2 spin state. In addition, multinuclear iron complexes [(dipyrrin)Fe₂(μ-O^tBu)₂ (3) and [(dipyrrin)Fe₃(μ-SAr)₃ (4) were designed and synthesized. The structures of the complexes were characterized by single crystal X-ray diffraction and UV-visible absorption spectroscopy, etc. 
       2. We found that the high-spin trivalent "iron(III)-alkoxy" complex (dipyrrin)₂Fe-OAr^tBu₃ (2) can effectively promote the polymerization of ε-caprolactone. The poly(ε-caprolactone) (PCL) with high molecular weight and narrow molecular weight distribution (Mn = 84.87 × 10³ g/mol，PDI = 1.25) was obtained under the catalyst loading of 0.1 mol%. The kinetic studies show that the polymerization of ε-caprolactone conforms to the first-order kinetic law. Complex 2 also has high catalytic activity on δ-valerolactone. High molecular weight and narrow molecular weight distribution of polyvalerolactone (Mn = 49.88 × 10³ g/mol, PDI = 1.50) could be produced under 0.25 mol% catalyst loading, and the polymerization effect was well. Based on the high catalytic activity of complex 2 on the two monomers, the copolymerization of ε-caprolactone and δ-valerolactone was carried out in one pot method to obtain PCL-PVL (Mn = 115.29 × 10³ g/mol，PDI = 1.77 , at 0.25 mol% catalyst loading) with certain elasticity and viscosity.