Cho Dong-Gyu, Plitt Patrick, Kim Sung Kuk, Lynch Vincent, Hong Seong-Jin, Lee Chang-Hee, Sessler Jonathan L
Department of Chemistry and Biochemistry and Institute for Cellular and Molecular Biology, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712-0165, USA.
J Am Chem Soc. 2008 Aug 13;130(32):10502-3. doi: 10.1021/ja804090w. Epub 2008 Jul 19.
The synthesis and characterization of a new sapphyrin analogue, dioxabenzosapphyrin, are reported. The benzodifuran moiety upon which this system is based leads to the incorporation of two oxygen atoms within the central macrocyclic core, thus replacing two protonated nitrogen centers found in normal pentaaza sapphyrin derivatives, including those derived from benzodipyrroles. As expected, the loss of these two NH hydrogen bond donor sites greatly reduces the anion affinity for the diprotonated form, even though the overall charge is the same as in the corresponding sapphyrins. Interestingly, dioxabenzosapphyrin, but not the corresponding all-aza systems, is found to bind neutral guests, such as phenol and 4-nitrophenol, albeit weakly. This latter finding highlights a potentially new application for core-modified expanded porphyrin derivatives, namely, as receptors for hydrogen bond donating neutral substrates.
报道了一种新型蓝宝石啉类似物二氧杂苯并蓝宝石啉的合成与表征。该体系所基于的苯并二呋喃部分导致在中心大环核心中引入两个氧原子，从而取代了在正常五氮杂蓝宝石啉衍生物（包括那些衍生自苯并二吡咯的衍生物）中发现的两个质子化氮中心。正如预期的那样，尽管总电荷与相应的蓝宝石啉相同，但这两个NH氢键供体位点的缺失极大地降低了二质子化形式对阴离子的亲和力。有趣的是，发现二氧杂苯并蓝宝石啉能结合中性客体，如苯酚和4-硝基苯酚，尽管结合较弱，但相应的全氮杂体系却不能结合。后一发现突出了核心修饰的扩展卟啉衍生物的一种潜在新应用，即作为氢键供体中性底物的受体。
