Koch Felix, Berkefeld Andreas, Speiser Bernd, Schubert Hartmut
Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, Germany.
Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, Germany.
Chemistry. 2017 Nov 21;23(65):16681-16690. doi: 10.1002/chem.201704599. Epub 2017 Nov 9.
Sulfur-bridged binuclear structures [2M-2S] play a pivotal role in a variety of chemical processes such as bond breaking and formation and electron transfer. In general, structural persistence is deemed essential to the respective function but owing to the lack of a suitable molecular model system, the current understanding of the factors that control the thermodynamic and kinetic stability of [2M-2S] cores clearly is limited. This work reports a series of binuclear complexes of nickel derived from a 1,4-terphenyldithiophenol ligand platform that is ideally suited for mechanistic work to overcome this limitation. Redox-induced assembly and disassembly of S-bridged [2M-2S] fragments have been investigated at the molecular level. As part of an extended square scheme, metastable binuclear structures that are significant mechanistically have been identified, characterized, and their reactivity studied quantitatively. Electronic properties that are inherent to [2M-2S] structures and determine thermodynamic and kinetic stability are differentiated from steric effects imposed by co-ligands.
硫桥连双核结构[2M - 2S]在各种化学过程中发挥着关键作用，如键的断裂与形成以及电子转移。一般来说，结构持久性被认为对各自的功能至关重要，但由于缺乏合适的分子模型系统，目前对控制[2M - 2S]核心热力学和动力学稳定性的因素的理解显然有限。这项工作报道了一系列源自1,4 - 三联苯二硫酚配体平台的镍双核配合物，该平台非常适合进行机理研究以克服这一限制。已在分子水平上研究了氧化还原诱导的S桥连[2M - 2S]片段的组装和解离。作为扩展方形方案的一部分，已鉴定、表征了具有重要机理意义的亚稳双核结构，并对其反应活性进行了定量研究。[2M - 2S]结构固有的决定热力学和动力学稳定性的电子性质与共配体施加的空间效应得以区分。
