Synthesis and Retrostructural Analysis of Libraries of AB<sub>3</sub> and Constitutional Isomeric AB<sub>2</sub> Phenylpropyl Ether-Based Supramolecular Dendrimers
作者:Virgil Percec、Mihai Peterca、Monika J. Sienkowska、Marc A. Ilies、Emad Aqad、Jan Smidrkal、Paul A. Heiney
DOI:10.1021/ja060062a
日期:2006.3.1
We report the synthesis of methyl esters of 3-(4-hydroxyphenyl)propionic, 3-(3,4-dihydroxyphenyl)propionic, 3-(3,5-dihydroxyphenyl)propionic, and 3-(3,4,5-trihydroxyphenyl)propionic acids and their use in a convergent iterative strategy to prepare up to four generations of three libraries, one of 3,4,5- and two of constitutional isomeric 3,4- and 35-substituted 3-phenylpropyl dendrons. Each library contains 3-[3,4,5-tris(dodecyl-1-oxy)phenyl]propyl-, 3-[3,4-bis(dodecyl-1-oxy)phenyl]propyl-, 3,4-bis[3-(4-dodecyl-1-oxyphenyl)propyl-1-oxy]phenyl-1-propyl-, and 3-13,4,5-tris[3-(4-dodecyl-1-oxyphenyl)propyl-1-oxy]phenyllpropyI ether first-generation clendrons on their periphery and -CO2CH3, -COOH, and -CH2OH groups at their apex. Regardless of their generation number and their periphery, internal, and apex structures, these dendrons self-assemble into supramolecular dendrimers that self-organize into all periodic and quasi-periodic assemblies encountered previously and in several unencountered with architecturally related benzyl ether-based supramolecular dendrimers. A variety of porous columnar lattices that were previously obtained only from clendritic dipepticles and hollow supramolecular spheres were also discovered from these building blocks. The more flexible and less compact 3-phenylpropyl ether repeat units are stable under acidic conditions, facilitate a simpler synthetic strategy, provide faster dynamics of self-assembly into higher-order supramolecular structures of larger dimensions, exhibit lower transition temperatures than the corresponding benzyl ether homologues, and demonstrate the generality of the self-assembly concept based on amphiphilic dendrons.