Synthesis, Structure, and Properties of Azatriangulenium Salts
Synthesis, Structure, and Properties of Azatriangulenium Salts
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氮三角鎓盐的合成、结构和性质
DOI：
10.1002/1521-3765(20010417)7:8
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
F. Krebs
中科院分区：
文献类型：
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作者：
B. Laursen;F. Krebs
已经开发并研究了吖啶鎓和三角鎓类型的新型氮桥杂环碳鎓离子的一般合成路线。该合成方法基于伯胺对三(2,6-二甲氧基苯基)碳鎓离子(1)的亲核芳香取代(SNAr)，凭借其逐步和不可逆的性质，为制备多种新型杂环碳鎓盐提供了有力的工具。三种新的氧桥和/或氮桥三角鎓盐的几种衍生物，氮杂二氧杂- (6)、二氮杂氧- (7) 和三氮杂三角鎓 (4)，已被合成，并研究了它们的物理化学性质。报道了化合物 2b-PF6、2d-PF6、4b-BF4、4c-BF4、6e-BF4 和 8 的晶体结构。讨论了与离子的静电和空间填充要求相关的三氮杂三古伦鎓盐的不同堆积模式。阳离子 6a、7b 和 4a 的稳定性（用其 pKR+ 值表示）已在强碱性非水溶液中使用 C_ 酸度函数测定；获得的值分别为 14.5、19.4 和 23.7。这项研究进一步表明，目前形式的 C_ 量表不适合精确测定超过 22 的 pKR+ 值。
A general synthetic route to novel nitrogen-bridged heterocyclic carbenium ions of the acridinium and triangulenium type has been developed and investigated. The synthetic method is based on nucleophilic aromatic substitution (SNAr) on the tris(2,6-dimethoxyphenyl)carbenium ion (1) with primary amines and, by virtue of its stepwise and irreversible nature, provides a powerful tool for the preparation of a wide variety of new heterocyclic carbenium salts. Several derivatives of the three new oxygen- and/or nitrogen-bridged triangulenium salts, azadioxa- (6), diazaoxa- (7), and triazatriangulenium (4), have been synthesized and their physicochemical properties have been investigated. Crystal structures for compounds 2 b-PF6, 2 d-PF6, 4b-BF4, 4c-BF4, 6e-BF4, and 8 are reported. The different packing modes found for the triazatriagulenium salts are discussed in relation to the electrostatic and space-filling requirements of the ions. The stabilities of the cations 6a, 7b, and 4a, as expressed by their pKR+ values, have been determined in strongly basic nonaqueous solution by use of the C_ acidity function; the values obtained were 14.5, 19.4, and 23.7, respectively. This study further implied that the C_ scale in its present form is unsuitable for the precise determination of pKR+ values beyond 22.