Chiral 27-membered [3+3] Schiff-base macrocycles and their reactivity with first-row transition metal ions
Chiral 27-membered [3+3] Schiff-base macrocycles and their reactivity with first-row transition metal ions
复制标题
DOI：
10.1016/j.poly.2007.12.003
复制
发表时间：
2008-02-26
期刊：
影响因子：
2.6
通讯作者：
Gou, Shaohua
中科院分区：
文献类型：
--
作者：
Chu, Zhaolian;Huang, Wei;Gou, Shaohua
27-以2，6-二甲酰基-4-取代苯酚（1中R = Cl，2中R = CH 3）为原料，与对映体[（1 R，2 R）或（1 S，2S）]和外消旋的反式-1，2-环己烷二胺进行[3 + 3]模板缩合反应，合成了席夫碱大环化合物1和2。其中两个手性[3 + 3]大环单晶骨架中的（S，S）-1和（R，R）-2已被结构表征。它们都有三角形的孔（类似于42.36埃（2）），其中相邻分子的一个苯环通过π-π堆积相互作用作为客体插入，质心-质心间距为3.599埃。用具有不同抗衡离子的某些第一行过渡金属盐[Cu（II）、Zn（II）、Fe（III）]处理上述大环，由于大环的尺寸匹配效应以及所使用的中心金属和抗衡离子的配位几何形状的限制，导致席夫碱C = N双键的断裂和大环的降解。合成了[2 + 2]、[2 + 1]和[1 + 2]型配合物（（R，R）-3，4，5，6）。在6的情况下，在甲醇中产生新型的二甲缩醛络合物，其中FeCl 3用作反应性刘易斯酸催化剂。圆二色性（CD）光谱证实了大环化合物及其过渡金属配合物的内在手性差异。(C)2008爱思唯尔有限公司保留所有权利。
27-Membered Schiff-base macrocycles 1 and 2 are prepared via the [3 + 3] template condensation of 2,6-diformyl-4-substituted phenol (R = Cl in 1 and R = CH3 in 2) with enantiomeric [(1R,2R) or (1S,2S)] and racemic trans-cyclohexane-1,2-diamines. Among them two chiral [3 + 3] macrocyclic single-crystals (S,S)-1 and (R,R)-2 in their backbones have been structurally characterized. Both of them have triangular holes (similar to 42.36 angstrom(2)) in which one phenyl ring of the neighboring molecule is inserted as a guest by pi-pi stacking interactions with the centroid-centroid separation of 3.599 angstrom. The treatment of aforementioned macrocycles with certain first-row transition metal salts [Cu(II), Zn(II), Fe(III)] with different counterions leads to the cleavage of Schiff-base C = N double bonds and degradation of the macrocycles due to the size matching effect of macrocycles as well as the restriction of coordination geometry of the central metals and the counterions used. As a result, [2 + 2], [2 + 1] and [1 + 2] types of complexes ((R,R)-3, 4, 5 and 6) are yielded. In the case of 6, a new type of dimethyl acetal complex is produced in methanol where FeCl3 serves as a reactive Lewis acid catalyst. The intrinsic chiral differences of the macrocycles and their transition metal complexes are demonstrated by circular dichroism (CD) spectra. (C) 2008 Elsevier Ltd. All rights reserved.