A phase separation event in solutions of some polymers is characterized by a lower critical solution temperature (LCST) and is often referred to as the coil-globule (C-G) transition. In particular, we postulated that this phenomenon should be accessible in supramolecular systems if the correct morphology and intermolecular interactions as well as an appropriate balance of hydrophobicity and hydrophilicity could be incorporated. We selected triphenylene as an aggregate-forming molecule and introduced at its periphery ternary amine substituents through alkoxy linkages. Structure of the resulting molecule 2,3,6,7,10,1 1-Hexakis(2-(N,N-diethylamino)ethoxy)triphenylene 1 can be seen in Figure la. We have observed a process analogous to the coil-globule transition of polymers but in a small molecular system (i.e. M(l) = 919.33 g/mol) as seen in Figure lb. We have also assessed the impact of 'supramolecular' forces by including a triphenylene moiety that should promote intermolecular aggregation and found that while this appears to increase the efficacy of the C-G transition it is not necessary for operation of the C-G transition. Thus, while the mechanism of LCST in polymers is relatively well understood the phenomenon in molecular systems can be more complex due to the introduction of supramolecular effects (plausible mechanism is suggested in Figure 1c).
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