Stimuli-responsive dendrimers. Towards tunable catalysts (DENDSWITCH)

催化是进行化学转化的独特工具，众所周知，实验参数的细微变化可能会对催化反应的结果产生巨大影响。树枝状催化剂具有结合均相催化剂和多相催化剂的优点和最大限度地减少缺点的潜力。事实上，它们可以溶于溶剂，但它们拥有大量明确的催化中心，并且由于它们的大尺寸，它们可以很容易地从产品中分离出来(并重复使用)。已经提出了几种树枝状催化剂，说明了这一领域日益重要的研究。然而，到目前为止，使用树枝状催化剂很少或根本没有探索到催化的整个部分。尤其是使用由温度、光、pH或电化学驱动的可切换(刺激响应)催化剂的情况，其中外部刺激将被用来改变空间(咬合角、空间需求)和/或电子(σ供体/π受体)性质或诱导半易变行为。他们随意改变催化活性和关闭或激活催化剂以触发催化事件的应用将被仔细审查。

Catalysis is a unique tool to carry out chemical transformations, and it is well established that subtle changes in experimental parameters could have a dramatic effect on the outcome of catalytic reactions. Dendritic catalysts have the potential for combining the advantages and minimizing the disadvantages of homogeneous and heterogeneous catalysts. Indeed, they are soluble in solvents, but they possess a large and well-defined number of catalytic sites and they can be easily separated from the products (and reused) due to their large size. Several dendritic catalysts have been proposed already, illustrating the growing importance of this field of research. However, whole sections of catalysis have been scarcely or not at all explored up to now using dendritic catalysts. This is in particular the case for using “switchable” (stimuli-responsive) catalysts, which are driven by temperature, light, pH, or electrochemically, where the external stimulus will be used to vary the steric (bite angle, steric demand) and/or electronic (σ-donor/π-acceptor) properties or to induce hemilabile behavior. Their application to change catalytic activity at will and shut down or activate catalysts to trigger catalytic events will be scrutinized.