1,10-Phenanthroline (phen) is one of the most popular ligands ever used in coordination chemistry due to its strong affinity for a wide range of metals with various oxidation states. Its polyaromatic structure provides robustness and rigidity, leading to intriguing features in numerous fields (luminescent coordination scaffolds, catalysis, supramolecular chemistry, sensors, theranostics, etc.). Importantly, phen offers eight distinct positions for functional groups to be attached, showcasing remarkable versatility for such a simple ligand. As a result, phen has become a landmark molecule for coordination chemists, serving as a must-use ligand and a versatile platform for designing polyfunctional arrays. The extensive use of substituted phenanthroline ligands with different metal ions has resulted in a diverse array of complexes tailored for numerous applications. For instance, these complexes have been utilized as sensitizers in dye-sensitized solar cells, as luminescent probes modified with antibodies for biomaterials, and in the creation of elegant supramolecular architectures like rotaxanes and catenanes, exemplified by Sauvage’s Nobel Prize-winning work in 2016. In summary, phen has found applications in almost every facet of chemistry. An intriguing aspect of phen is the specific reactivity of each pair of carbon atoms ([2,9], [3,8], [4,7], and [5,6]), enabling the functionalization of each pair with different groups and leading to polyfunctional arrays. Furthermore, it is possible to differentiate each position in these pairs, resulting in non-symmetrical systems with tremendous versatility. In this Review, the authors aim to compile and categorize existing synthetic strategies for the stepwise polyfunctionalization of phen in various positions. This comprehensive toolbox will aid coordination chemists in designing virtually any polyfunctional ligand. The survey will encompass seminal work from the 1950s to the present day. The scope of the Review will be limited to 1,10-phenanthroline, excluding ligands with more intracyclic heteroatoms or fused aromatic cycles. Overall, the primary goal of this Review is to highlight both old and recent synthetic strategies that find applicability in the mentioned applications. By doing so, the authors hope to establish a first reference for phenanthroline synthesis, covering all possible positions on the backbone, and hope to inspire all concerned chemists to devise new strategies that have not yet been explored.

中文翻译：

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菲咯啉的五十度色：1,10-菲咯啉所有位置功能化的合成策略

1,10-菲咯啉 (phen) 是配位化学中最常用的配体之一，因为它对多种具有不同氧化态的金属具有很强的亲和力。其多芳香族结构具有坚固性和刚性，在许多领域（发光配位支架、催化、超分子化学、传感器、治疗诊断学等）具有有趣的特性。重要的是，phen 为要连接的官能团提供了八个不同的位置，展示了这种简单配体的显着多功能性。因此，phen 已成为配位化学家的标志性分子，作为必须使用的配体和设计多功能阵列的通用平台。具有不同金属离子的取代菲咯啉配体的广泛使用产生了适合多种应用的多种配合物。例如，这些复合物已被用作染料敏化太阳能电池中的敏化剂、生物材料用抗体修饰的发光探针，以及用于创建轮烷和索烷等优雅的超分子结构，Sauvage 于 2016 年获得诺贝尔奖的工作就是例证。总之，phen 几乎在化学的各个方面都有应用。 phen 的一个有趣的方面是每对碳原子（[2,9]、[3,8]、[4,7] 和 [5,6]）的特定反应性，使得每对碳原子具有不同的功能化基团并导致多功能阵列。此外，可以区分这些对中的每个位置，从而产生具有巨大多功能性的非对称系统。在这篇综述中，作者的目的是对现有的苯酚在不同位置的逐步多官能化合成策略进行汇编和分类。这个综合工具箱将帮助配位化学家设计几乎任何多功能配体。该调查将涵盖 20 世纪 50 年代至今的开创性工作。审查范围仅限于1,10-菲咯啉，不包括具有更多环内杂原子或稠合芳香环的配体。总的来说，本次综述的主要目标是强调在上述应用中适用的旧的和最新的合成策略。通过这样做，作者希望为菲咯啉合成建立第一个参考，涵盖主干上所有可能的位置，并希望激励所有相关化学家设计尚未探索的新策略。