Fluorous Dendrimers and Methods for Production Thereof
申请人:Percec Virgil
公开号:US20120277460A1
公开(公告)日:2012-11-01
The present invention concerns the design of an environmentally friendly and efficient fluorous phase based on dendritic architectures containing short semifluorinated groups on their periphery.
Complex Columnar Hexagonal Polymorphism in Supramolecular Assemblies of a Semifluorinated Electron-Accepting Naphthalene Bisimide
作者:Yu-Chun Wu、Pawaret Leowanawat、Hao-Jan Sun、Benjamin E. Partridge、Mihai Peterca、Robert Graf、Hans W. Spiess、Xiangbing Zeng、Goran Ungar、Chain-Shu Hsu、Paul A. Heiney、Virgil Percec
DOI:10.1021/ja510643b
日期:2015.1.21
Simple synthetic methods for a strongly electron-accepting naphthalene bisimide (NBI) derivative functionalized with a new environmentally friendly chiral racemic semifluorinated alkyl group and with AB(3) minidendrons containing the same semifluorinated group are reported. The semifluorinated dendron was attached to the imide groups of the NBI via one, two, and three (m = 1, 2, 3) methylenic units. The NBI-containing semifluorinated groups and the dendronized NBI with m = 1 and 2 self-organize into lamellar crystals. The dendronized NBI with m = 3 self-assembles into an unprecedentedly complex and ordered column that self-organizes in a columnar hexagonal periodic array. This array undergoes a continuous transition to a columnar hexagonal superlattice that does not display a first-order phase transition during analysis by differential scanning calorimetry at heating and cooling rates of 10 and 1 degrees C/min. These complex columnar hexagonal periodic arrays with intramolecular order could be elucidated only by a combination of powder and fiber X-ray diffraction studies and solid-state NMR experiments. The lamellar crystals self-organized from m = 1 and the two highly ordered columnar hexagonal periodic arrays of m = 3 are assembled via thermodynamically controlled processes. Since strongly electron-accepting derivatives are of great interest to replace fullerene acceptors in organic photovoltaics and for other supramolecular electronic materials, the multitechnique structural analysis methodology elaborated here must be taken into consideration in all related studies.