Buildup of amphiphilic molecular bola from organic-inorganic hybrid polyoxometalates and their vesicle-like supramolecular assembly.
Buildup of amphiphilic molecular bola from organic-inorganic hybrid polyoxometalates and their vesicle-like supramolecular assembly.
复制标题
DOI：
10.1002/chem.201101966
复制
发表时间：
2011-10
期刊：
影响因子：
--
通讯作者：
Fengping Xiao;Mauricio F. Misdrahi;Jin Zhang;Panchao Yin;J. Hao;Chunlin Lv;Zicheng Xiao;Tianbo Liu-Tian
中科院分区：
文献类型：
--
作者：
Fengping Xiao;Mauricio F. Misdrahi;Jin Zhang;Panchao Yin;J. Hao;Chunlin Lv;Zicheng Xiao;Tianbo Liu-Tian
两亲性分子是一类重要的功能化合物，在化学、生物学和材料科学中可通过自组装形成所谓的“软材料”。[1]在这类分子中，bola两亲物（具有疏水骨架和两个亲水端基的分子）自从Fuhrhop关于琥珀酸的疏水衍生物的自组装性质的开创性工作以来受到越来越多的关注。[2]这是由于它们作为构建块来制备各种功能结构的潜力，例如用于光电器件、膜模拟、纳米反应器和药物递送的胶束、囊泡、纤维、膜、管、带和绳。[3，4]虽然许多官能团已被用作表面活性分子的末端单元，但具有两个有机衍生的聚氧乙烯酸酯（POM）作为末端基团的bola两亲物，一类独特的金属氧化物簇与有机配体接枝，[5-9]从未报道过。在有机衍生化的多金属氧酸盐中，亚氨基取代的多金属氧酸盐由于其在催化、光电器件和医药等方面的潜在应用而引起了人们的极大兴趣。[7]特别是，我们最近发现，在单取代的烷基亚氨基六钼酸盐[Mo 6 O 18 NCH 2（R）] 2 H2中，靠近氮原子的两个饱和sp3 CCH 2 H键可以被附近的POM活化，并且可以在高温下通过所谓的双取代偶联（DDHC）反应形成碳-碳双键C= C。[10]在很大程度上，由于Maatta，[11] Errington，[12]和Proust的开创性工作，[13]制备有机酰亚胺POM的方法逐步变得方便。[7]如今，已经合成了许多这样的新衍生物，特别是通过直接使用胺作为原起始材料的所谓的N，N '-二环己基碳二亚胺（DCC）方案。[7，14]然而，它们中很少有作为二亚氨基配体的衍生物获得的，[15，16]特别是因为柔性的可变长度的二胺的反应阻止了许多发展。因此，在先前关于刚性杂化分子哑铃的工作之后，[15 c]我们试图引入一系列柔性配体，例如，具有邻烷氧基链取代基的功能性双芳基胺，以构建互连POM杂化物的构建，包括聚氧杂环芳烷，一类基于POM的金属大环。[16a]在此，我们展示了用这种类型的二胺制备基于POM的两亲性分子bola。据我们所知，两亲性POM杂化物由于其在人工胶囊催化和药物递送方面的潜力而引起了越来越多的关注。[17][nBu 4 N] 4ACHTUNGTRENNUNG [α-Mo 8 O26]的回流反应（nBu 4 N = TBA）与双芳胺（1，2-双（邻氨基苯氧基）乙烷，C2; 1，4-双（邻氨基苯氧基）丁烷，C4;或1，6-双（邻氨基苯氧基）己烷、C6）盐酸盐和DCC，摩尔比为2：1：1。3在无水乙腈中的溶液顺利进行，得到两亲分子bola双有机亚胺桥连的六钼酸盐：[nBu 4 N] 4ACHTUNGTRENNUNG [Mo 6 O 18（N，N '-NC 6 H4 OCnH 2nOC 6 H4 N）Mo 6 O 18]（n= 2（1），4（2），6（3）），产率为50-70%（方案1）。
Amphiphilic molecules are a class of the most important functional compounds, which can be utilized to build up socalled “soft materials” by self-assembly in chemistry, biology, and material sciences.[1] Of this class of molecules, bolaamphiphiles (molecules with a hydrophobic skeleton and two hydrophilic end groups) have received increasing attention since Fuhrhop s seminal work on the self-assembly properties of hydrophobic derivatives of succinic acid.[2] This is due to their potential as building blocks to prepare various functional structures, such as micelles, vesicles, fibers, membranes, tubes, ribbons, and ropes for photoelectric devices, membrane-mimicking, nanoreactors, and drug delivery.[3, 4] Although many functional groups have been used as the end unit of surface-active molecules, a bolaamphiphile with two organically derivatized polyoxometalates (POMs) as end groups, a class of unique metal oxide clusters grafted with organic ligands,[5–9] has never been reported. Among organically derivatized POMs, we are much more interested in organoimido-substituted POMs due to their potential applications in catalysis, photoelectric devices, and medicines.[7] In particular, we have recently discovered that two saturated sp3 CÀH bonds near the nitrogen atom in the monosubstituted alkylimido hexamolybdates,[Mo6O18NCH2 (R)] 2À, can be activated by the nearby POM, and a carbon–carbon double bond, C= C, can be formed at elevated temperature through the so-called doubly dehydrogenative coupling (DDHC) reaction.[10] Thanks largely to the pioneering work of Maatta,[11] Errington,[12] and Proust,[13] the method of preparing organoimido POMs became convenient step by step.[7] Nowadays, many such new derivatives have been synthesized, especially with the so-called N, N’-dicyclohexylcarbodiimide (DCC) protocol by direct use of amines as the raw starting materials.[7, 14] However, few of them are obtained as the derivatives of diimido ligands,[15, 16] especially since the reaction of flexible, alterable-length diamines prevents many from developing. Thus, following previous work on rigid hybrid molecular dumbbells,[15c] we attempt to introduce a series of flexible ligands, for example, functional bisarylamines with o-alkoxy chain substituents, to construct the buildup of interconnected POM hybrids including polyoxometalatocyclophanes, a class of POM-based matallomacrocycles.[16a] Herein, we demonstrate the fabrication of POM-based amphiphilic molecular bola with this type of diamine. To the best of our knowledge, amphiphilic POM hybrids have attracted increasing attention due to their potential in artificial capsules for catalysis and drug delivery.[17]Refluxing reactions of [nBu4N] 4ACHTUNGTRENNUNG [α-Mo8O26](nBu4N= TBA) with bisarylamine (1, 2-bis (o-aminophenoxy) ethane, C2; 1, 4-bis (o-aminophenoxy) butane, C4; or 1, 6-bis (o-aminophenoxy) hexane, C6) hydrochlorides, and DCC with a molar ratio of 2: 1: 3 in dry acetonitrile proceeded smoothly and afforded the amphiphilic molecular bola bisorganoimido-bridged hexamolybdates:[nBu4N] 4ACHTUNGTRENNUNG [Mo6O18 (N, N’-NC6H4OCnH2nOC6H4N) Mo6O18](n= 2 (1), 4 (2), 6 (3)), in 50–70% yields (Scheme 1).