Synthesis and Aggregation Properties of Water‐Soluble Newkome‐Dendronized Perylenetetracarboxdiimides

Abstract

Abstract The synthesis and characterization of three highly water‐soluble perylenetetracarboxdiimide (“perylene bisimide”, PBI) dyes 1 and 2b is presented. The water solubility is provided by peripheral dendronization with 1G‐ and 2G‐Newkome dendrons. The aggregation behaviour of these amphiphiles in water and that of their tert ‐butyl‐protected precursor molecules 3 and 4 in organic solvents was investigated by UV/Vis‐ and fluorescence spectroscopy. The symmetric 1G‐dendronized dye 1a forms aggregates more easily than its 2G‐counterpart 1b . The asymmetric derivatives 2b reveals pronounced aggregation properties due to the presence of both a 2G‐dendron and a flexible and non‐bulky dodecyl substituent. The 1G‐analogue 2a is insoluble in water as a result of insufficient overall hydrophilicity caused by only one 1G‐Newkome dendron. Within the series of water‐soluble perylenes 1 and 2b the asymmetric derivative 2b forms the most regularly shaped micelles in water (pH = 7.2) with a mean diameter of 16 nm as demonstrated by transition electron microscopy (TEM). The bola‐amphiphiles 1a and 1b form a distribution of smaller aggregates on average with less defined shape.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)