Phosphinine- and Phosphacyclohexadienyl-Complexes: Novel Phosphorus Compounds for the Activation of Small Molecules and for Homogeneous Catalytic Reactions

在第一个资助期取得成功的基础上，沃尔夫(雷根斯堡大学)和穆勒(柏林自由大学)研究小组之间的联合项目将继续进行到下一阶段。本课题研究的重点是吡啶的高级同系物--Hück-芳香族λ-3-σ-2-膦(磷苯)。由于它们不同的配位方式和良好的π受体性质，这些配体表现出非常多才多艺的配位化学。特别是，它们非常适合于低氧化态过渡金属络合物的稳定，与小分子活化均相催化有关。此外，膦可以通过与有机锂或格氏试剂反应转化为阴离子1-R-磷酰环己二烯基，这也是过渡金属的重要配体。因此，膦及其衍生物可以用来获得不寻常的金属络合物和金属簇合物。在第一个供资期间，许多最初假定的关于膦基过渡金属络合物或磷环己二烯阴离子的合成和反应性的想法都得到了成功的实施。结果的多样性预示着第二阶段将是一个非常多方面的化学阶段，除了进一步研究基本的配位化学性质外，在(不对称)催化领域的应用将是重点。主要目标如下：i)开发双齿和三齿膦以及手性膦及其配位化合物；ii)用膦基钴和铁络合物活化小分子；iii)钴催化的氢甲酰化和氢化反应；iv)与轴向手性1-R-膦-环己二烯阴离子的氢功能化反应。我们两个研究小组(AK Wolf：高活性金属阴离子的合成、处理和应用；AK Müller：官能化膦的合成、反应性、配位化学和应用)的专业知识对于在第二个资助期成功实施这些计划中的广泛研究至关重要。

Building on a successful first funding period, the joint project between the Wolf (University of Regensburg) and Müller (Free University of Berlin) research groups will be continued into the next phase. This research project focuses on the Hückel-aromatic λ3σ2-phosphinines (phosphabenzenes), which are the higher homologues of pyridines. Due to their diverse coordination modes and good π-acceptor properties, these ligands exhibit an extremely versatile coordination chemistry. In particular, they are highly suitable for the stabilization of low-oxidation state transition metal complexes, relevant for small molecule activation homogeneous catalysis. Furthermore, phosphinines can be converted into anionic 1-R-phosphacyclohexadienyls by reaction with organolithium or Grignard reagents, which are also of interest as ligands for transition metals. Phosphinines and their derivatives can thus be used to access unusual metal complexes and metal clusters. In the course of the first funding period, many of the originally postulated ideas for the synthesis and reactivity of phosphinine-based transition metal complexes or phosphacyclohexadienyl anions were successfully implemented. The diversity of the results promises a very multifaceted chemistry in the second phase, where, in addition to further research into the basic coordination chemical properties, applications in the field of (asymmetric) catalysis will be particularly in the focus. The following major aims will be pursued: i) development of bi- and tridentate phosphinines as well as chiral phosphinines and their coordination compounds; ii) activation of small molecules with phosphinine-based Co- and Fe-complexes iii) cobalt-catalyzed hydroformylation and hydrogenation reactions; iv) hydrofunctionalization reactions with axially-chiral 1-R-phosphacyclohexadienyl anions. The expertise of our two research groups (AK Wolf: synthesis, handling and application of highly reactive metallate anions; AK Müller: synthesis, reactivity, coordination chemistry and application of functionalized phosphinines) will be crucial for the successful implementation of these planned extensive studies in the second funding period.