Department of Organic Chemistry, Universidad Autónoma de Madrid , Cantoblanco, 28049 Madrid, Spain.
IMDEA Nanociencia , Faraday 9, 28049 Madrid, Spain.
J Am Chem Soc. 2015 Oct 14;137(40):12914-22. doi: 10.1021/jacs.5b06454. Epub 2015 Oct 5.
To activate oxidative and/or reductive electron transfer reactions, N-pyridyl-substituted Sc3N@I(h)-C80 (4) and C60 (3) fulleropyrrolidines have been prepared and axially coordinated to electron-rich (1) or electron-deficient (2) Zn(II)phthalocyanines (Zn(II)Pcs) through zinc-pyridyl, metal-ligand coordination affording a full-fledged family of electron donor-acceptor ensembles. An arsenal of photophysical assays as they were carried out with, for example, 1/4 and 2/4 show unambiguously that a Zn(II)Pc-to-Sc3N@I(h)-C80 photoinduced electron transfer takes place in the former ensemble, whereas a Sc3N@I(h)-C80-to-Zn(II)Pc electron transfer occurs in the latter ensemble. To the best of our knowledge, this is the first time that a fullerene-based molecular building block shows an electron transfer dichotomy, namely acting both as electron-acceptor or electron-donor, and its outcome is simply governed by the electronic nature of its counterpart. In light of the latter, the present work, which involves the use of Sc3N@I(h)-C80, one of the most abundant and easy-to-purify endohedral metallofullerenes, is, on one hand, a paradigmatic change and, on the other hand, an important milestone en-route toward the construction of easy-to-prepare molecular materials featuring switchable electron transfer reactivity.
为了激活氧化还原电子转移反应，我们制备了 N-吡啶取代的 Sc3N@I(h)-C80（4）和 C60（3）富勒吡咯烷，并通过锌-吡啶、金属-配体配位将其轴向配位到富电子（1）或缺电子（2）的 Zn(II)酞菁（Zn(II)Pc）上，从而得到了一套完整的电子给体-受体配合物。我们进行了一系列光物理测定，例如 1/4 和 2/4，结果明确表明 Zn(II)Pc 到 Sc3N@I(h)-C80 的光诱导电子转移发生在前一个配合物中，而 Sc3N@I(h)-C80 到 Zn(II)Pc 的电子转移发生在后一个配合物中。据我们所知，这是首次证明富勒烯基分子砌块具有电子转移二分性，即既能作为电子受体，也能作为电子供体，其结果仅由其对应物的电子性质决定。鉴于后者，本工作涉及使用 Sc3N@I(h)-C80，它是最丰富和最容易纯化的内包金属富勒烯之一，一方面是一个典范的改变，另一方面是构建易于制备的分子材料的重要里程碑，这些材料具有可切换的电子转移反应性。
