Donor substituted alkynes as directional bridging ligands in polynuclear complexes

超分子配位化合物的显著性质突出了拟研究项目的背景，其中特定的炔配体确保了强的金属间偶联。不同金属中心的连接是由炔配体完成的，炔配体在两个α位置上都有给基。在三键上的侧对配位使主要的线性炔变成kappa2螯合配体。供体中心可以是一个碳原子或一个氧原子。具有末端供体基团的单核配合物可视为功能性配体。与中间过渡金属的炔配合物的高极化率和普遍的氧化还原活性可能导致炔配合物具有非常规的配位行为。这些定向桥接配体对其多核配合物特征的特定功能将通过供体中心的系统变化来阐明。该研究项目的主要课题是开发控制和逐步制备具有α -给体中心的炔的多核配合物的合成策略。反过来，这一目标取决于通过亲核取代从相应的W(II)-或W（IV）乙炔或卤代乙炔配合物中直接获得具有自由末端供体的炔配合物。这种在配位炔上的取代反应只是零星的，没有系统的研究。除了组装多核配位化合物外，通过这种策略还可以合成其他难以制造的炔。得到的多核配合物的电子结构将通过光谱学和理论进行全面的研究。在此基础上，将对这些新型配体系统的潜在应用进行比较分类和评价。

The background of the intended research project is highlighted by the remarkable properties of supramolecular coordination compounds, in which specific alkyne ligands ensure strong intermetallic coupling. The linkage of different metal centers is accomplished by alkyne ligands, which bear donor groups in both alpha-positions. Side-on coordination at the triple bond turns the primarily linear alkynes into kappa2-chelate ligands. The donor centers can be a chalcogen- or a pnicogen atom. Mononuclear complexes with terminal donor groups may be regarded as functional ligands. The large bite angles due to the bend back angle in the alkyne complex moiety, the high polarizability and the prevalent redox activity of alkyne complexes with mid transition metals may lead to an unconventional coordination behavior. The specific function of these directional bridging ligands for the characteristics of their polynuclear complexes will be elucidated by a systematic variation of the donor centers.The main topic of the research project is the development of synthetic strategies for the controlled and stepwise preparation of polynuclear complexes featuring alkynes with alpha-donor centers. In turn, this goal depends on a straightforward access to alkyne complexes with free terminal donors from corresponding W(II)- or W(IV) acetylene or halogenacetylene complexes via nucleophilic substitution. Such substitution reactions on the coordinated alkyne were only sporadically and not systematically investigated. In addition to the assembling of polynuclear coordination compounds, the synthesis of otherwise difficult to make alkynes might be possible by this strategy. The electronic structures of the obtained polynuclear complexes will be comprehensively studied by spectroscopy and theory. On this basis a comparative classification and evaluation with respect to potential applications of these novel ligand systems will be accomplished.