Stabilization of Acenes: “Geländer”-Pentacenes [data]

We report soluble tetrakis-biphenyl substituted pentacenes comprised of sp2 carbons and synthesized from pentacene-5,7,12,14-tetraone. Intramolecular Yamamoto coupling of two tetrakis(chlorobiphenylyl)pentacenes yields helical, doubly wrapped pentacenes, in which the quaterphenylene units solubilize the pentacenes and shield their central anthracene units to an unprecedented degree. The criss-cross-bridged pentacenes resist (photo)oxidation, Diels-Alder reactions and are much less reactive than TIPS-ethynylated pentacene. Extension of this concept might provide access to the larger acenes.

本研究报道了一类由sp²杂化碳原子构成、以并五苯-5,7,12,14-四酮为原料合成的可溶性四联苯取代并五苯。通过两个四(氯联苯基)并五苯的分子内山本耦合反应，可得到螺旋状双包裹型并五苯；其中四联苯单元不仅赋予并五苯可溶性，还以空前程度屏蔽了其中心蒽单元。这类交叉桥联并五苯可抵御(光)氧化与狄尔斯-阿尔德反应，其反应活性远低于三异丙基硅基乙炔基取代(TIPS-ethynylated)并五苯。该策略的拓展有望为更大并苯类化合物的合成提供新途径。