π-low transition temperature mixtures with widely-tunable polarity and ultralow viscosity for synthesizing chiral nanomaterials.

Abstract

Low transition temperature mixtures (LTTMs) formed via typical hydrogen bonds hold significant potential in diverse applications. However, constructing π-rich LTTMs composed entirely of aromatic components is rare. In this work, we report a series of π-LTTMs using phenols and aromatic ketones. The rigid skeletons of aromatic planes introduce steric congestion that enhances molecular free volume, yielding low viscosities. They show viscosities as low as 2.12 cP, which is among the lowest values of LTTMs. The phase transition temperature is showed as -73.5 °C, which is low level within the LTTM family. These π-LTTMs allow for fast mass transportation rate, potentially behaving as media for reaction and self-assembly. Owing to their low phase transition temperature and pronounced tendency toward supercooling, these systems form room-temperature liquids over extremely broad composition ranges. Over a wide ratio of components, widely tunable polarity is realized, which greatly expands the feasibility in synthesizing of chiral nanomaterials. The π-liquids accelerate one-dimensional growth and enable expression of macroscopic chirality for a chiral amide-based building block.