Synthesis, characterization, and modeling of a functional conjugated microporous polymer: ₂ storage and light harvesting

Abstract

Rationalization of structure and properties of amorphous porous solids at the microscopic level is essential in developing advanced materials. We delineate the structural modeling of a designed tetraphenylethene-based amorphous conjugated microporous polymer TPE-CMP (1) and its gas storage and photophysical properties. The polymer 1 exhibits high specific surface area of 854 m²/g. 1 showed appreciable CO₂ (32.4 wt %) uptake at 195 K up to 1 atm and 31.6 wt % at 273 K up to 35 bar. The structural model of 1 obtained through computational methods is quantitatively consistent with experimental observations. The microporous structural model of 1 was further validated by a calculation of CO₂ adsorption isotherm obtained through GCMC simulations. Quantum chemical calculations were employed to understand the nature of interactions of CO₂ with the constituents of the framework 1. π–π interaction with strength of 19 kJ/mol was observed between CO₂ and the phenyl rings of TPE. 1 shows strong turn-on greenish-yellow emission due to the restriction of phenyl ring rotation of TPE node. This framework induced emission (FIE) of microporous polymer 1 is further exploited for light-harvesting applications by noncovalent encapsulation of a suitable acceptor dye, rhodamine B (RhB), in the framework.