Synthesis and crystal structure of the bromide salt of the inside protonated form of the cage amine [(2.3)3]adamanzane, 1,4,8,12-tetraazatricyclo[6.6.3.24,12]nonadecane and synthesis of the bowl amine [(2.3)2.21]adamanzane, 1,5,9,12-tetraazabicyclo[7.5.2]hexadecane
作者:Johan Springborg、Bente Nielsen、Carl Erik Olsen、Inger Søtofte
DOI:10.1039/a906244k
日期:——
The reaction of 1,4,7-triazacyclononane with tris(3-chloropropyl)amine affords the inside monoprotonated form of the tricyclic amine 1,4,8,12-tetraazatricyclo[6.6.3.24,12]nonadecane (3), which was isolated as the bromide salt, [H[(2.3)3]adz]Br (yield 38%). The crystal structure of [H[(2.3)3]adz]Br·4H2O has been solved by X-ray diffraction at T = 120 K. In the i+,i,i,i-H[(2.3)3]adz+ cation (3a) the acidic hydrogen atom and the lone pairs of the nitrogen atoms are oriented towards the inside of the cavity. The acidic hydrogen atom is attached to the apical nitrogen atom and both are positioned on a three-fold axis. The distances between the nitrogen atoms are in the range of 2.73(2)–2.99(1) Å. The inside coordinated proton in H[(2.3)3]adz+ (3a) is unusually inert to reaction with base (kdiss < 4 × 10–9 s–1 at 25 °C in 0.01 M NaOD). From 1H and 13C NMR it is concluded that in slightly acidic (pH > 2) and in basic aqueous solutions the dominant form of the cage has all four lone pairs pointing into the cavity. In concentrated strong acid protonation occurs and is believed to involve inversion at one or several of the bridgehead nitrogen atoms. In concentrated boiling hydrochloric acid the cage undergoes a slow cleavage of one trimethylene bridge to give the bowl amine [(2.3)2.21]adz (7), 1,5,9,12-tetraazabicyclo[7.5.2]hexadecane, which was isolated as the triprotonated bromide dichloride salt, [H3[(2.3)2.21]adz]BrCl2·H2O (yield 40%).
1,4,7-三氮杂环壬烷与三(3-氯丙基)胺反应后,得到三环胺 1,4,8,12-四氮杂三环[6.6.3.24,12]壬烷 (3) 的内部单质子化形式,并分离出溴化物盐 [H[(2.3)3]adz]Br(产率 38%)。在 i+,i,i,i-H[(2.3)3]adz+阳离子(3a)中,酸性氢原子和氮原子的孤对朝向空腔内部。酸性氢原子与顶端的氮原子相连,两者都位于三折轴上。氮原子间的距离在 2.73(2)-2.99(1) Å 之间。H[(2.3)3]adz+ (3a) 中的内配位质子与碱反应异常惰性(在 0.01 M NaOD 溶液中,25 °C 时 kdiss < 4 × 10-9 s-1)。通过 1H 和 13C NMR 可以得出结论:在微酸性(pH 值大于 2)和碱性水溶液中,笼子的主要形式是四个孤对全部指向空腔。在浓强酸中会发生质子化,据信这涉及桥头氮原子中一个或几个原子的反转。在浓沸点盐酸中,笼子中的一个三亚甲基桥发生缓慢裂解,生成碗胺[(2.3)2.21]adz (7)、1,5,9,12-四氮杂双环[7.5.2]十六烷,并分离出三质子化溴化物二氯化物盐 [H3[(2.3)2.21]adz]BrCl2-H2O(产率 40%)。