Pentaindenocorannulene and tetraindenocorannulene:: New aromatic hydrocarbon π systems with curvatures surpassing that of C60
Pentaindenocorannulene and tetraindenocorannulene:: New aromatic hydrocarbon π systems with curvatures surpassing that of C60
复制标题
DOI：
10.1021/ja067487h
复制
发表时间：
2007-01-24
影响因子：
15
通讯作者：
Scott, Lawrence T.
中科院分区：
文献类型：
--
作者：
Jackson, Edward A.;Steinberg, Brian D.;Scott, Lawrence T.
报告了两种新的测地聚芳烃五并并环烯 (1, C50H20) 和四并并环烯 (2, C44H18) 的短合成和 X 射线晶体结构。这些扩展的芳香系统构成了迄今为止制备的最大的 C-60 弯曲亚基。与理论预测一致，这些新碳氢化合物核心的三角碳原子比 C-60 的碳原子表现出更大的金字塔化（1、2 和 C-60 的平均 POAV 角分别为 12.6、12.1 和 11.6 度）。这些通过溶液相方法从源自平面起始材料的化合物开始通过溶液相方法合成这种高度弯曲的系统，明确地证明富勒烯、碳纳米管和相关富碳分子的合理化学合成都应该仅使用溶液化学方法来实现！不必采用高温气相热解。 1的合成始于1,3,5,7,9-五氯鸟环烯与2-氯苯基硼酸的5倍Suzuki-Miyaura偶联，得到1,3,5,7,9-五(2-氯苯基)鸟环烯，分离产率为48%（每次C-C偶联平均产率为86%）。随后通过 5 倍 Pd(0) 催化的分子内芳基化反应，以 35% 的分离收率（每次 C-C 偶联平均收率 81%）转化为五并环烯 (1)。四并八环烯 (2) 的合成遵循相同的过程，但从 1,2,5,6-四溴八环烯开始。中间体 1,2,5,6-四(2-氯苯基)蛇环烯的快速真空热解也产生四并蛇环烯 (2)。标题化合物均为深橙色、耐热、空气稳定的结晶固体（熔点 >400 摄氏度），具有丰富的紫外-可见光谱，在可见光区域具有长吸收尾。
Short syntheses and X-ray crystal structures are reported for two new geodesic polyarenes, pentaindenocorannulene (1, C50H20) and tetraindenocorannulene (2, C44H18). These extended aromatic systems constitute the largest curved subunits of C-60 ever prepared. In agreement with theoretical predictions, the trigonal carbon atoms at the cores of these new hydrocarbons suffer even greater pyramidalization than that exhibited by the carbon atoms of C-60 (average POAV angles = 12.6, 12.1, and 11.6 degrees for 1, 2, and C-60, respectively). These syntheses of such highly curved systems by solution phase methods, starting from compounds that were derived from planar starting materials also by solution phase methods, demonstrate unequivocally that rational chemical syntheses of fullerenes, carbon nanotubes, and related carbon-rich molecules should all be possible using exclusively solution chemical methods! Recourse to high-temperature gas-phase pyrolysis should not be necessary. The synthesis of 1 begins with a 5-fold Suzuki-Miyaura coupling of 1,3,5,7,9-pentachlorocorannulene with 2-chlorophenylboronic acid, giving 1,3,5,7,9-pentakis(2-chlorophenyl)corannulene in 48% isolated yield (86% average yield per C-C coupling). Subsequent conversion to pentaindenocorannulene (1) was achieved in 35% isolated yield (81% average yield per C-C coupling) by a 5-fold, Pd(0)-catalyzed, intramolecular arylation reaction. The synthesis of tetraindenocorannulene (2) follows the same course but starts from 1,2,5,6-tetrabromocorannulene. Flash vacuum pyrolysis of the intermediate 1,2,5,6-tetrakis(2-chlorophenyl)corannulene also produces tetraindenocorannulene (2). The title compounds are both deep orange, thermally robust, air stable, crystalline solids (mp >400 degrees C) with rich UV-vis spectra that have long absorption tails in the visible region.